linux.git/Documentation/admin-guide/sysctl, branch v7.2-rc1 Linux kernel source tree Merge tag 'mm-stable-2026-06-18-09-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm 2026-06-19T17:14:34+00:00 Linus Torvalds torvalds@linux-foundation.org 2026-06-19T17:14:34+00:00 a552c81ff4a16738ca5a44a177d552eb38d552ce Pull MM updates from Andrew Morton: - "selftests/mm: clean up build output and verbosity" (Li Wang) Remove some noise from the MM selftests build - "mm: Free contiguous order-0 pages efficiently" (Ryan Roberts) Speed up the freeing of a batch of 0-order pages by first scanning them for coalescing opportunities. This is applicable to vfree() and to the releasing of frozen pages - "mm/damon: introduce DAMOS failed region quota charge ratio" (SeongJae Park) Address a DAMOS usability issue: The DAMOS quota often exhausts prematurely because it charges for all memory attempted, causing slow and inconsistent performance when actions fail on unreclaimable memory. To fix this, a new feature lets users set a smaller, flexible quota charge ratio (via a numerator and denominator) for failed regions. Since failed actions cause less overhead, reducing their quota cost ensures more predictable and efficient DAMOS processing - "selftests/cgroup: improve zswap tests robustness and support large page sizes" (Li Wang) Fix various spurious failures and improves the overall robustness of the cgroup zswap selftests - "fix MAP_DROPPABLE not supported errno" (Anthony Yznaga) Fix an issue in the mlock selftests on arm32 - "mm: huge_memory: clean up defrag sysfs with shared" (Breno Leitao) Some maintenance work in the huge_memory code - "treewide: fixup gfp_t printks" (Brendan Jackman) Use the special vprintf() gfp_t conversion in various places - "mm: Fix vmemmap optimization accounting and initialization" (Muchun Song) Fix several bugs in the vmemmap optimization, mainly around incorrect page accounting and memmap initialization in the DAX and memory hotplug paths. It also fixes pageblock migratetype initialization and struct page initialization for ZONE_DEVICE compound pages - "mm/damon: repost non-hotfix reviewed patches in damon/next tree" A sprinkle of unrelated minor bugfixes for DAMON - "mm: remove page_mapped()" (David Hildenbrand) Remove this function from the tree, replacing it with folio_mapped() - "mm/damon: let DAMON be paused and resumed" (SeongJae Park) Allow DAMON to be paused and resumed without losing its current state - "kasan: hw_tags: Disable tagging for stack and page-tables" (Muhammad Usama Anjum) Simplify and speed up kasan by removing its ineffective tagging of stacks and page tables - "mm/damon/reclaim,lru_sort: monitor all system rams by default" (SeongJae Park) Simplify deployment on diverse hardware like NUMA systems by updating DAMON_RECLAIM and DAMON_LRU_SORT to automatically monitor the physical address range covering all System RAM areas by default, replacing the overly restrictive behavior that only targeted the single largest memory block to save on negligible overhead - "mm/damon/sysfs: document filters/ directory as deprecated" (SeongJae Park) Update some DAMON docs - "mm: use spinlock guards for zone lock" (Dmitry Ilvokhin) Switch zone->lock handling over to using the guard() mechanisms - "mm/filemap: tighten mmap_miss hit accounting" (fujunjie) Fix a flaw where the mmap_miss counter over-credited page cache hits during fault-arounds and page-fault retries. This results in significant reduction of redundant synchronous mmap readahead I/O, drastically cutting down execution time and gigabytes read for sparse random or strided memory access workloads - "selftests/cgroup: Fix false positive failures in test_percpu_basic" (Li Wang) Fix a couple of false-positives in the cgroup kmem selftests - "mm/damon/reclaim: support monitoring intervals auto-tuning" (SeongJae Park) Add a new parameter to DAMON permitting DAMON_RECLAIM to automatically tune DAMON's sampling and aggregation intervals - "mm/damon/stat: add kdamond_pid parameter" (SeongJae Park) Change DAMON_STAT to provide the pid of its kdamond - "mm/kmemleak: dedupe verbose scan output" (Breno Leitao) Remove large amounts of duplicated backtraces from the verbose-mode kmemleak output - "mm: remove CONFIG_HAVE_BOOTMEM_INFO_NODE (Part 1)" (David Hildenbrand) Reduce our use of CONFIG_HAVE_BOOTMEM_INFO_NODE, with a view to removing it entirely in a later series - "mm/damon: validate min_region_size to be power of 2" (Liew Rui Yan) Prevent users from passing a non-power-of-2 value of `addr_unit', as this later results in undesirable behavior - "mm: document read_pages and simplify usage" (Frederick Mayle) - "tools/mm/page-types: Fix misc bugs" (Ye Liu) Fix three issues in tools/mm/page-types.c - "mm: misc cleanups from __GFP_UNMAPPED series" (Brendan Jackman) Implement several cleanups in the page allocator and related code - "mm, swap: swap table phase IV: unify allocation" (Kairui Song) Unify the allocation and charging of anon and shmem swap in folios, provides better synchronization, consolidates the metadata management, hence dropping the static array and map, and improves performance - "mm/damon: introduce data attributes monitoring" (SeongJae Park( Extend DAMON to monitor general data attributes other than accesses - "mm/vmalloc: free unused pages on vrealloc() shrink" (Shivam Kalra) Implement the TODO in vrealloc() to unmap and free unused pages when shrinking across a page boundary - "mm/damon: documentation and comment fixes" (niecheng) - "remove mmap_action success, error hooks" (Lorenzo Stoakes) Eliminate custom hooks from mmap_action by removing the problematic success_hook which allowed drivers to improperly access uninitialized VMAs. It replaces the error_hook with a simple error-code field and updates the memory char driver accordingly - "mm/damon: minor improvements for code readability and tests" (SeongJae Park) - "mm/damon: fix macro arguments and clarify quota goals doc" (Maksym Shcherba) - "userfaultfd: merge fs/userfaultfd.c into mm/userfaultfd.c" (Mike Rapoport) - "mm/mglru: improve reclaim loop and dirty folio" (Kairui Song and others) Clean up and slightly improves MGLRU's reclaim loop and dirty writeback handling. Large performance improvements are measured - "use vma locks for proc/pid/{smaps|numa_maps} reads" (Suren Baghdasaryan) Use per-vma locks when reading /proc/pid/smaps and numa_maps similar to reduce contention on central mmap_lock - "refactors thpsize_shmem_enabled_store() and thpsize_shmem_enabled_show()" (Ran Xiaokai) Some cleanup work in the THP code - "selftests/memfd: fix compilation warnings" (Konstantin Khorenko) Fix a few build glitches in the memfd selftest code. - "memcg: shrink obj_stock_pcp and cache multiple objcgs" (Shakeel Butt) Resolve a 68% performance regression caused by NUMA-node cache thrashing around struct obj_stock_pcp by shrinking its existing fields and expanding it into a multi-slot array that caches up to five obj_cgroup pointers per CPU, allowing per-node variants of the same memcg to coexist within a single 64-byte cache line. - "zram: writeback fixes" (Sergey Senozhatsky) address a couple of unrelated zram writeback issues - "mm: switch THP shrinker to list_lru" (Johannes Weiner) Resolve NUMA-awareness issues and streamlines callsite interaction by refactoring and extending the list_lru API to completely replace the complex, open-coded deferred split queue for Transparent Huge Pages - "mm: improve large folio readahead for exec memory" (Usama Arif) Improve large-folio readahead on systems like 64K-page arm64 by preventing the mmap_miss check from permanently disabling target-oriented VM_EXEC readahead, and by generalizing the force_thp_readahead gate to support mappings with any usefully large maximum folio order under the cache cap. - "userfaultfd/pagemap: pre-existing fixes" (Kiryl Shutsemau) Fix a bunch of minor issues in the userfaultfd/pagemap, all of which were flagged by Sashiko review of proposed new material - "mm/sparse-vmemmap: Provide generic vmemmap_set_pmd() and vmemmap_check_pmd()" (Muchun Song) Provide generic versions of these two functions so the four arch-specific implementations can be removed. - "mm/swap, PM: hibernate: fix swapoff race in uswsusp by pinning swap device" (Youngjun Park) Address a uswsusp-vs-swapoff race and reduces the swap device reference taking/releasing frequency. - "mm/hmm: A fix and a selftest" (Dev Jain) * tag 'mm-stable-2026-06-18-09-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (321 commits) selftests/mm/hmm-tests: test pagemap reads of PMD device-private entries fs/proc/task_mmu: do not warn on seeing non-migration pmd entry lib/test_hmm: check alloc_page_vma() return value and handle OOM mm/compaction: cap compact_gap() at COMPACT_CLUSTER_MAX mm/swap: remove redundant swap device reference in alloc/free mm/swap, PM: hibernate: fix swapoff race in uswsusp by pinning swap device mm/filemap: use folio_next_index() for start vmalloc: fix NULL pointer dereference in is_vm_area_hugepages() sparc/mm: drop vmemmap_check_pmd helper and use generic code loongarch/mm: drop vmemmap_check_pmd helper and use generic code riscv/mm: drop vmemmap_pmd helpers and use generic code arm64/mm: drop vmemmap_pmd helpers and use generic code mm/sparse-vmemmap: provide generic vmemmap_set_pmd() and vmemmap_check_pmd() rust: page: mark Page::nid as inline userfaultfd: build __VMA_UFFD_FLAGS from config-gated masks userfaultfd: gate must_wait writability check on pte_present() mm/huge_memory: preserve pmd_swp_uffd_wp on device-private PMD downgrade fs/proc/task_mmu: fix hugetlb self-deadlock in pagemap_scan_pte_hole() fs/proc/task_mmu: use huge_page_size() in pagemap_scan_hugetlb_entry() fs/proc/task_mmu: fix make_uffd_wp_huge_pte() prot-update race ... 
Pull MM updates from Andrew Morton:

 - "selftests/mm: clean up build output and verbosity" (Li Wang)

   Remove some noise from the MM selftests build

 - "mm: Free contiguous order-0 pages efficiently" (Ryan Roberts)

   Speed up the freeing of a batch of 0-order pages by first scanning
   them for coalescing opportunities. This is applicable to vfree() and
   to the releasing of frozen pages

 - "mm/damon: introduce DAMOS failed region quota charge ratio"
   (SeongJae Park)

   Address a DAMOS usability issue: The DAMOS quota often exhausts
   prematurely because it charges for all memory attempted, causing slow
   and inconsistent performance when actions fail on unreclaimable
   memory.

   To fix this, a new feature lets users set a smaller, flexible quota
   charge ratio (via a numerator and denominator) for failed regions.
   Since failed actions cause less overhead, reducing their quota cost
   ensures more predictable and efficient DAMOS processing

 - "selftests/cgroup: improve zswap tests robustness and support large
   page sizes" (Li Wang)

   Fix various spurious failures and improves the overall robustness of
   the cgroup zswap selftests

 - "fix MAP_DROPPABLE not supported errno" (Anthony Yznaga)

   Fix an issue in the mlock selftests on arm32

 - "mm: huge_memory: clean up defrag sysfs with shared" (Breno Leitao)

   Some maintenance work in the huge_memory code

 - "treewide: fixup gfp_t printks" (Brendan Jackman)

   Use the special vprintf() gfp_t conversion in various places

 - "mm: Fix vmemmap optimization accounting and initialization" (Muchun
   Song)

   Fix several bugs in the vmemmap optimization, mainly around incorrect
   page accounting and memmap initialization in the DAX and memory
   hotplug paths. It also fixes pageblock migratetype initialization and
   struct page initialization for ZONE_DEVICE compound pages

 - "mm/damon: repost non-hotfix reviewed patches in damon/next tree"

   A sprinkle of unrelated minor bugfixes for DAMON

 - "mm: remove page_mapped()" (David Hildenbrand)

   Remove this function from the tree, replacing it with folio_mapped()

 - "mm/damon: let DAMON be paused and resumed" (SeongJae Park)

   Allow DAMON to be paused and resumed without losing its current state

 - "kasan: hw_tags: Disable tagging for stack and page-tables" (Muhammad
   Usama Anjum)

   Simplify and speed up kasan by removing its ineffective tagging of
   stacks and page tables

 - "mm/damon/reclaim,lru_sort: monitor all system rams by default"
   (SeongJae Park)

   Simplify deployment on diverse hardware like NUMA systems by updating
   DAMON_RECLAIM and DAMON_LRU_SORT to automatically monitor the
   physical address range covering all System RAM areas by default,
   replacing the overly restrictive behavior that only targeted the
   single largest memory block to save on negligible overhead

 - "mm/damon/sysfs: document filters/ directory as deprecated" (SeongJae
   Park)

   Update some DAMON docs

 - "mm: use spinlock guards for zone lock" (Dmitry Ilvokhin)

   Switch zone->lock handling over to using the guard() mechanisms

 - "mm/filemap: tighten mmap_miss hit accounting" (fujunjie)

   Fix a flaw where the mmap_miss counter over-credited page cache hits
   during fault-arounds and page-fault retries. This results in
   significant reduction of redundant synchronous mmap readahead I/O,
   drastically cutting down execution time and gigabytes read for sparse
   random or strided memory access workloads

 - "selftests/cgroup: Fix false positive failures in test_percpu_basic"
   (Li Wang)

   Fix a couple of false-positives in the cgroup kmem selftests

 - "mm/damon/reclaim: support monitoring intervals auto-tuning"
   (SeongJae Park)

   Add a new parameter to DAMON permitting DAMON_RECLAIM to
   automatically tune DAMON's sampling and aggregation intervals

 - "mm/damon/stat: add kdamond_pid parameter" (SeongJae Park)

   Change DAMON_STAT to provide the pid of its kdamond

 - "mm/kmemleak: dedupe verbose scan output" (Breno Leitao)

   Remove large amounts of duplicated backtraces from the verbose-mode
   kmemleak output

 - "mm: remove CONFIG_HAVE_BOOTMEM_INFO_NODE (Part 1)" (David
   Hildenbrand)

   Reduce our use of CONFIG_HAVE_BOOTMEM_INFO_NODE, with a view to
   removing it entirely in a later series

 - "mm/damon: validate min_region_size to be power of 2" (Liew Rui Yan)

   Prevent users from passing a non-power-of-2 value of `addr_unit', as
   this later results in undesirable behavior

 - "mm: document read_pages and simplify usage" (Frederick Mayle)

 - "tools/mm/page-types: Fix misc bugs" (Ye Liu)

   Fix three issues in tools/mm/page-types.c

 - "mm: misc cleanups from __GFP_UNMAPPED series" (Brendan Jackman)

   Implement several cleanups in the page allocator and related code

 - "mm, swap: swap table phase IV: unify allocation" (Kairui Song)

   Unify the allocation and charging of anon and shmem swap in folios,
   provides better synchronization, consolidates the metadata
   management, hence dropping the static array and map, and improves
   performance

 - "mm/damon: introduce data attributes monitoring" (SeongJae Park(

   Extend DAMON to monitor general data attributes other than accesses

 - "mm/vmalloc: free unused pages on vrealloc() shrink" (Shivam Kalra)

   Implement the TODO in vrealloc() to unmap and free unused pages when
   shrinking across a page boundary

 - "mm/damon: documentation and comment fixes" (niecheng)

 - "remove mmap_action success, error hooks" (Lorenzo Stoakes)

   Eliminate custom hooks from mmap_action by removing the problematic
   success_hook which allowed drivers to improperly access uninitialized
   VMAs. It replaces the error_hook with a simple error-code field and
   updates the memory char driver accordingly

 - "mm/damon: minor improvements for code readability and tests"
   (SeongJae Park)

 - "mm/damon: fix macro arguments and clarify quota goals doc" (Maksym
   Shcherba)

 - "userfaultfd: merge fs/userfaultfd.c into mm/userfaultfd.c" (Mike
   Rapoport)

 - "mm/mglru: improve reclaim loop and dirty folio" (Kairui Song and
   others)

   Clean up and slightly improves MGLRU's reclaim loop and dirty
   writeback handling. Large performance improvements are measured

 - "use vma locks for proc/pid/{smaps|numa_maps} reads" (Suren
   Baghdasaryan)

   Use per-vma locks when reading /proc/pid/smaps and numa_maps similar
   to reduce contention on central mmap_lock

 - "refactors thpsize_shmem_enabled_store() and thpsize_shmem_enabled_show()"
   (Ran Xiaokai)

   Some cleanup work in the THP code

 - "selftests/memfd: fix compilation warnings" (Konstantin Khorenko)

   Fix a few build glitches in the memfd selftest code.

 - "memcg: shrink obj_stock_pcp and cache multiple objcgs" (Shakeel
   Butt)

   Resolve a 68% performance regression caused by NUMA-node cache
   thrashing around struct obj_stock_pcp by shrinking its existing
   fields and expanding it into a multi-slot array that caches up to
   five obj_cgroup pointers per CPU, allowing per-node variants of the
   same memcg to coexist within a single 64-byte cache line.

 - "zram: writeback fixes" (Sergey Senozhatsky)

   address a couple of unrelated zram writeback issues

 - "mm: switch THP shrinker to list_lru" (Johannes Weiner)

   Resolve NUMA-awareness issues and streamlines callsite interaction by
   refactoring and extending the list_lru API to completely replace the
   complex, open-coded deferred split queue for Transparent Huge Pages

 - "mm: improve large folio readahead for exec memory" (Usama Arif)

   Improve large-folio readahead on systems like 64K-page arm64 by
   preventing the mmap_miss check from permanently disabling
   target-oriented VM_EXEC readahead, and by generalizing the
   force_thp_readahead gate to support mappings with any usefully large
   maximum folio order under the cache cap.

 - "userfaultfd/pagemap: pre-existing fixes" (Kiryl Shutsemau)

   Fix a bunch of minor issues in the userfaultfd/pagemap, all of which
   were flagged by Sashiko review of proposed new material

 - "mm/sparse-vmemmap: Provide generic vmemmap_set_pmd() and
   vmemmap_check_pmd()" (Muchun Song)

   Provide generic versions of these two functions so the four
   arch-specific implementations can be removed.

 - "mm/swap, PM: hibernate: fix swapoff race in uswsusp by pinning swap
   device" (Youngjun Park)

   Address a uswsusp-vs-swapoff race and reduces the swap device
   reference taking/releasing frequency.

 - "mm/hmm: A fix and a selftest" (Dev Jain)

* tag 'mm-stable-2026-06-18-09-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (321 commits)
  selftests/mm/hmm-tests: test pagemap reads of PMD device-private entries
  fs/proc/task_mmu: do not warn on seeing non-migration pmd entry
  lib/test_hmm: check alloc_page_vma() return value and handle OOM
  mm/compaction: cap compact_gap() at COMPACT_CLUSTER_MAX
  mm/swap: remove redundant swap device reference in alloc/free
  mm/swap, PM: hibernate: fix swapoff race in uswsusp by pinning swap device
  mm/filemap: use folio_next_index() for start
  vmalloc: fix NULL pointer dereference in is_vm_area_hugepages()
  sparc/mm: drop vmemmap_check_pmd helper and use generic code
  loongarch/mm: drop vmemmap_check_pmd helper and use generic code
  riscv/mm: drop vmemmap_pmd helpers and use generic code
  arm64/mm: drop vmemmap_pmd helpers and use generic code
  mm/sparse-vmemmap: provide generic vmemmap_set_pmd() and vmemmap_check_pmd()
  rust: page: mark Page::nid as inline
  userfaultfd: build __VMA_UFFD_FLAGS from config-gated masks
  userfaultfd: gate must_wait writability check on pte_present()
  mm/huge_memory: preserve pmd_swp_uffd_wp on device-private PMD downgrade
  fs/proc/task_mmu: fix hugetlb self-deadlock in pagemap_scan_pte_hole()
  fs/proc/task_mmu: use huge_page_size() in pagemap_scan_hugetlb_entry()
  fs/proc/task_mmu: fix make_uffd_wp_huge_pte() prot-update race
  ...
Merge tag 'net-next-7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 2026-06-17T07:17:00+00:00 Linus Torvalds torvalds@linux-foundation.org 2026-06-17T07:17:00+00:00 b85966adbf5de0668a815c6e3527f87e0c387fb4 Pull networking updates from Jakub Kicinski: "Core & protocols: - Work on removing rtnl_lock protection throughout the stack continues. In this chapter: - don't use rtnl_lock for IPv6 multicast routing configuration - don't take rtnl_lock in ethtool for modern drivers - prepare Qdisc dump callbacks for rtnl_lock removal - Support dumping just ifindex + name of all interfaces, under RCU. It's a common operation for Netlink CLI tools (when translating names to ifindexes) and previously required full rtnl_lock. - Support dumping qdiscs and page pools for a specific netdev. Even tho user space wants a dump of all netdevs, most of the time, the OOO programming model results in repeating the dump for each netdev. Which, in absence of a cache, leads to a O(n^2) behavior. - Flush nexthops once on multi-nexthop removal (e.g. when device goes down), another O(n^2) -> O(n) improvement. - Rehash locally generated traffic to a different nexthop on retransmit timeout. - Honor oif when choosing nexthop for locally generated IPv6 traffic. - Convert TCP Auth Option to crypto library, and drop non-RFC algos. - Increase subflow limits in MPTCP to 64 and endpoint limit to 256. - Support MPTCP signaling of IPv6 address + port (ADD_ADDR). We need to selectively skip reporting of the standard TCP Timestamp option, because they won't fit into the header space together (12 + 30 > 40). - Support using bridge neighbor suppression, Duplicate Address Detection, Gratuitous ARP and unsolicited NA forwarding - in EVPN deployments, e.g. VXLAN fabrics (IPv4 and IPv6). - Improve link state reporting for upper netdevs (e.g. macvlan) over tunnel devices (again, mostly for EVPN deployments). - Support binding GENEVE tunnels to a local address. - Speed up UDP tunnel destruction (remove one synchronize_rcu()). - Support exponential field encoding in multicast (IGMPv3 and MLDv2). - Support attaching PSP crypto offload to containers (veth, netkit). - Add a new IPSec Netlink message XFRM_MSG_MIGRATE_STATE that allows migrating individual IPsec SAs independently of their policies. The existing XFRM_MSG_MIGRATE is tightly coupled to policy+SA migration, lacks SPI for unique SA identification, and cannot express reqid changes or migrate Transport mode selectors. The new interface identifies the SA via SPI and mark, supports reqid changes, address family changes, encap removal, and uses an atomic create+install flow under x->lock to prevent SN/IV reuse during AEAD SA migration. - Implement GRO/GSO support for PPPoE. - Convert sockopt callbacks in a number of protocols to iov_iter. Cross-tree stuff: - Remove support for Crypto TFM cloning (unblocked after the TCP Auth Option rework). This feature regressed performance for all crypto API users, since it changed crypto transformation objects into reference-counted objects. - Add FCrypt-PCBC implementation to rxrpc and remove it from the global crypto API as obsolete and insecure. Wireless: - Major rework of station bandwidth handling, fixing issues with lower capability than AP. - Cleanups for EMLSR spec issues (drafts differed). - More Neighbor Awareness Networking (Wi-Fi Aware) work (multicast, schedule improvements, multi-station etc.) - Some Ultra High Reliability (UHR) / IEEE 802.11bn (D1.4) work (e.g. non-primary channel access, UHR DBE support). - Fine Timing Measurement ranging (i.e. distance measurement) APIs. Netfilter: - Use per-rule hash initval in nf_conncount. This avoids unnecessary lock contention with short keys (e.g. conntrack zones) in different namespaces. - Various safety improvements, both in packet parsing and object lifetimes. Notably add refcounts to conntrack timeout policy. Deletions: - Remove TLS + sockmap integration. TLS wants to pin user pages to avoid a copy, and sockmap wants to write to the input stream. More work on this integration is clearly needed, and we can't find any users (original author admitted that they never deployed it). - Remove support for TLS offload with TCP Offload Engine (the far more common opportunistic offload is retained). The locking looks unfixable (driver sleeps under TCP spin locks) and people from the vendor that added this are AWOL. - Remove more ATM code, trying to leave behind only what PPPoATM needs, AAL5 and br2684 with permanent circuits. - Remove AppleTalk. Let it join hamradio in our out of tree protocol graveyard, I mean, repository. - Disable 32-bit x_tables compatibility (32bit binaries on 64bit kernel) interface in user namespaces. To be deleted completely, soon. - Remove 5/10 MHz support from cfg80211/mac80211. Drivers: - Software: - Support DEVMEM/DMABUF Tx over NETMEM_TX_NO_DMA devices (netkit) - bonding: add knob to strictly follow 802.3ad for link state - New drivers: - Alibaba Elastic Ethernet Adaptor (cloud vNIC). - NXP NETC switch within i.MX94. - DPLL: - Add operational state to pins (implement in zl3073x). - Add generic DPLL type, for daisy-chaining DPLLs (implement in ice). - Ethernet high-speed NICs: - Huawei (hinic3): - enhance tc flow offload support with queue selection, tunnels - nVidia/Mellanox: - avoid over-copying payload to the skb's linear part (up to 60% win for LRO on slow CPUs like ARM64 V2) - expose more per-queue stats over the standard API - support additional, unprivileged PFs in the DPU configuration - support Socket Direct (multi-PF) with switchdev offloads - add a pool / frag allocator for DMA mapped buffers for control objects, save memory on systems with 64kB page size - take advantage of the ability to dynamically change RSS table size, even when table is configured by the user - increase the max RSS table size for even traffic distribution - Ethernet NICs: - Marvell/Aquantia: - AQC113 PTP support - Realtek USB (r8152): - support 10Gbit Link Speeds and Energy-Efficient Ethernet (EEE) - support firmware loaded (for RTL8157/RTL8159) - support for the RTL8159 - Intel (ixgbe): - support Energy-Efficient Ethernet (EEE) on E610 devices - Ethernet switches: - Airoha: - support multiple netdevs on a single GDM block / port - Marvell (mv88e6xxx): - support SERDES of mv88e6321 - Microchip (ksz8/9): - rework the driver callbacks to remove one indirection layer - Motorcomm (yt921x): - support port rate policing - support TBF qdisc offload - support ACL/flower offload - nVidia/Mellanox: - expose per-PG rx_discards - Realtek: - rtl8365mb: bridge offloading and VLAN support - Ethernet PHYs: - Airoha: - support Airoha AN8801R Gigabit PHYs. - Micrel: - implement 3 low-loss cable tunables - Realtek: - support MDI swapping for RTL8226-CG - support MDIO for RTL931x - Qualcomm: - at803x: Rx and Tx clock management for IPQ5018 PHY - Motorcomm: - support YT8522 100M RMII PHY - set drive strength in YT8531s RGMII - TI: - dp83822: add optional external PHY clock - Bluetooth: - hci_sync: add support for HCI_LE_Set_Host_Feature [v2] - SMP: use AES-CMAC library API - Intel: - support Product level reset - support smart trigger dump - Mediatek: - add event filter to filter specific event - Realtek: - fix RTL8761B/BU broken LE extended scan - WiFi: - Broadcom (b43): - new support for a 11n device - MediaTek (mt76): - support mt7927 - mt792x: broken usb transport detection - mt7921: regulatory improvements - Qualcomm (ath9k): - GPIO interface improvements - Qualcomm (ath12k): - WDS support - replace dynamic memory allocation in WMI Rx path - thermal throttling/cooling device support - 6 GHz incumbent interference detection - channel 177 in 5 GHz - Realtek (rt89): - RTL8922AU support - USB 3 mode switch for performance - better monitor radiotap support - RTL8922DE preparations" * tag 'net-next-7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1778 commits) ipv4: fib_rule: Move fib4_rules_exit() to ->exit(). net: serialize netif_running() check in enqueue_to_backlog() net: skmsg: preserve sg.copy across SG transforms appletalk: move the protocol out of tree appletalk: stop storing per-interface state in struct net_device selftests/bpf: test that TLS crypto is rejected on a sockmap socket selftests/bpf: drop the unused kTLS program from test_sockmap selftests/bpf: remove sockmap + ktls tests tls: remove dead sockmap (psock) handling from the SW path tls: reject the combination of TLS and sockmap atm: remove orphaned uAPI for deleted drivers, protocols and SVCs atm: remove unused ATM PHY operations atm: remove the unused pre_send and send_bh device operations atm: remove the unused change_qos device operation atm: remove SVC socket support and the signaling daemon interface atm: remove the local ATM (NSAP) address registry atm: remove dead SONET PHY ioctls atm: remove the unused send_oam / push_oam callbacks atm: remove AAL3/4 transport support net: dsa: sja1105: fix lastused timestamp in flower stats ... 
Pull networking updates from Jakub Kicinski:
 "Core & protocols:

   - Work on removing rtnl_lock protection throughout the stack
     continues. In this chapter:
       - don't use rtnl_lock for IPv6 multicast routing configuration
       - don't take rtnl_lock in ethtool for modern drivers
       - prepare Qdisc dump callbacks for rtnl_lock removal

   - Support dumping just ifindex + name of all interfaces, under RCU.
     It's a common operation for Netlink CLI tools (when translating
     names to ifindexes) and previously required full rtnl_lock.

   - Support dumping qdiscs and page pools for a specific netdev. Even
     tho user space wants a dump of all netdevs, most of the time, the
     OOO programming model results in repeating the dump for each
     netdev. Which, in absence of a cache, leads to a O(n^2) behavior.

   - Flush nexthops once on multi-nexthop removal (e.g. when device goes
     down), another O(n^2) -> O(n) improvement.

   - Rehash locally generated traffic to a different nexthop on
     retransmit timeout.

   - Honor oif when choosing nexthop for locally generated IPv6 traffic.

   - Convert TCP Auth Option to crypto library, and drop non-RFC algos.

   - Increase subflow limits in MPTCP to 64 and endpoint limit to 256.

   - Support MPTCP signaling of IPv6 address + port (ADD_ADDR). We need
     to selectively skip reporting of the standard TCP Timestamp option,
     because they won't fit into the header space together (12 + 30 >
     40).

   - Support using bridge neighbor suppression, Duplicate Address
     Detection, Gratuitous ARP and unsolicited NA forwarding - in EVPN
     deployments, e.g. VXLAN fabrics (IPv4 and IPv6).

   - Improve link state reporting for upper netdevs (e.g. macvlan) over
     tunnel devices (again, mostly for EVPN deployments).

   - Support binding GENEVE tunnels to a local address.

   - Speed up UDP tunnel destruction (remove one synchronize_rcu()).

   - Support exponential field encoding in multicast (IGMPv3 and MLDv2).

   - Support attaching PSP crypto offload to containers (veth, netkit).

   - Add a new IPSec Netlink message XFRM_MSG_MIGRATE_STATE that allows
     migrating individual IPsec SAs independently of their policies.

     The existing XFRM_MSG_MIGRATE is tightly coupled to policy+SA
     migration, lacks SPI for unique SA identification, and cannot
     express reqid changes or migrate Transport mode selectors.

     The new interface identifies the SA via SPI and mark, supports
     reqid changes, address family changes, encap removal, and uses an
     atomic create+install flow under x->lock to prevent SN/IV reuse
     during AEAD SA migration.

   - Implement GRO/GSO support for PPPoE.

   - Convert sockopt callbacks in a number of protocols to iov_iter.

  Cross-tree stuff:

   - Remove support for Crypto TFM cloning (unblocked after the TCP Auth
     Option rework). This feature regressed performance for all crypto
     API users, since it changed crypto transformation objects into
     reference-counted objects.

   - Add FCrypt-PCBC implementation to rxrpc and remove it from the
     global crypto API as obsolete and insecure.

  Wireless:

   - Major rework of station bandwidth handling, fixing issues with
     lower capability than AP.

   - Cleanups for EMLSR spec issues (drafts differed).

   - More Neighbor Awareness Networking (Wi-Fi Aware) work (multicast,
     schedule improvements, multi-station etc.)

   - Some Ultra High Reliability (UHR) / IEEE 802.11bn (D1.4) work
     (e.g. non-primary channel access, UHR DBE support).

   - Fine Timing Measurement ranging (i.e. distance measurement) APIs.

  Netfilter:

   - Use per-rule hash initval in nf_conncount. This avoids unnecessary
     lock contention with short keys (e.g. conntrack zones) in different
     namespaces.

   - Various safety improvements, both in packet parsing and object
     lifetimes. Notably add refcounts to conntrack timeout policy.

  Deletions:

   - Remove TLS + sockmap integration. TLS wants to pin user pages to
     avoid a copy, and sockmap wants to write to the input stream. More
     work on this integration is clearly needed, and we can't find any
     users (original author admitted that they never deployed it).

   - Remove support for TLS offload with TCP Offload Engine (the far
     more common opportunistic offload is retained). The locking looks
     unfixable (driver sleeps under TCP spin locks) and people from the
     vendor that added this are AWOL.

   - Remove more ATM code, trying to leave behind only what PPPoATM
     needs, AAL5 and br2684 with permanent circuits.

   - Remove AppleTalk. Let it join hamradio in our out of tree protocol
     graveyard, I mean, repository.

   - Disable 32-bit x_tables compatibility (32bit binaries on 64bit
     kernel) interface in user namespaces. To be deleted completely,
     soon.

   - Remove 5/10 MHz support from cfg80211/mac80211.

  Drivers:

   - Software:
       - Support DEVMEM/DMABUF Tx over NETMEM_TX_NO_DMA devices (netkit)
       - bonding: add knob to strictly follow 802.3ad for link state

   - New drivers:
       - Alibaba Elastic Ethernet Adaptor (cloud vNIC).
       - NXP NETC switch within i.MX94.

   - DPLL:
       - Add operational state to pins (implement in zl3073x).
       - Add generic DPLL type, for daisy-chaining DPLLs (implement in ice).

   - Ethernet high-speed NICs:
       - Huawei (hinic3):
           - enhance tc flow offload support with queue selection,
             tunnels
       - nVidia/Mellanox:
           - avoid over-copying payload to the skb's linear part (up to
             60% win for LRO on slow CPUs like ARM64 V2)
           - expose more per-queue stats over the standard API
           - support additional, unprivileged PFs in the DPU
             configuration
           - support Socket Direct (multi-PF) with switchdev offloads
           - add a pool / frag allocator for DMA mapped buffers for
             control objects, save memory on systems with 64kB page size
           - take advantage of the ability to dynamically change RSS
             table size, even when table is configured by the user
           - increase the max RSS table size for even traffic
             distribution

   - Ethernet NICs:
       - Marvell/Aquantia:
           - AQC113 PTP support
       - Realtek USB (r8152):
           - support 10Gbit Link Speeds and Energy-Efficient Ethernet
             (EEE)
           - support firmware loaded (for RTL8157/RTL8159)
           - support for the RTL8159
       - Intel (ixgbe):
           - support Energy-Efficient Ethernet (EEE) on E610 devices

   - Ethernet switches:
       - Airoha:
           - support multiple netdevs on a single GDM block / port
       - Marvell (mv88e6xxx):
           - support SERDES of mv88e6321
       - Microchip (ksz8/9):
           - rework the driver callbacks to remove one indirection layer
       - Motorcomm (yt921x):
           - support port rate policing
           - support TBF qdisc offload
           - support ACL/flower offload
       - nVidia/Mellanox:
           - expose per-PG rx_discards
       - Realtek:
           - rtl8365mb: bridge offloading and VLAN support

   - Ethernet PHYs:
       - Airoha:
           - support Airoha AN8801R Gigabit PHYs.
       - Micrel:
           - implement 3 low-loss cable tunables
       - Realtek:
           - support MDI swapping for RTL8226-CG
           - support MDIO for RTL931x
       - Qualcomm:
           - at803x: Rx and Tx clock management for IPQ5018 PHY
       - Motorcomm:
           - support YT8522 100M RMII PHY
           - set drive strength in YT8531s RGMII
       - TI:
           - dp83822: add optional external PHY clock

   - Bluetooth:
       - hci_sync: add support for HCI_LE_Set_Host_Feature [v2]
       - SMP: use AES-CMAC library API
       - Intel:
           - support Product level reset
           - support smart trigger dump
       - Mediatek:
           - add event filter to filter specific event
       - Realtek:
           - fix RTL8761B/BU broken LE extended scan

   - WiFi:
       - Broadcom (b43):
           - new support for a 11n device
       - MediaTek (mt76):
           - support mt7927
           - mt792x: broken usb transport detection
           - mt7921: regulatory improvements
       - Qualcomm (ath9k):
           - GPIO interface improvements
       - Qualcomm (ath12k):
           - WDS support
           - replace dynamic memory allocation in WMI Rx path
           - thermal throttling/cooling device support
           - 6 GHz incumbent interference detection
           - channel 177 in 5 GHz
       - Realtek (rt89):
           - RTL8922AU support
           - USB 3 mode switch for performance
           - better monitor radiotap support
           - RTL8922DE preparations"

* tag 'net-next-7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1778 commits)
  ipv4: fib_rule: Move fib4_rules_exit() to ->exit().
  net: serialize netif_running() check in enqueue_to_backlog()
  net: skmsg: preserve sg.copy across SG transforms
  appletalk: move the protocol out of tree
  appletalk: stop storing per-interface state in struct net_device
  selftests/bpf: test that TLS crypto is rejected on a sockmap socket
  selftests/bpf: drop the unused kTLS program from test_sockmap
  selftests/bpf: remove sockmap + ktls tests
  tls: remove dead sockmap (psock) handling from the SW path
  tls: reject the combination of TLS and sockmap
  atm: remove orphaned uAPI for deleted drivers, protocols and SVCs
  atm: remove unused ATM PHY operations
  atm: remove the unused pre_send and send_bh device operations
  atm: remove the unused change_qos device operation
  atm: remove SVC socket support and the signaling daemon interface
  atm: remove the local ATM (NSAP) address registry
  atm: remove dead SONET PHY ioctls
  atm: remove the unused send_oam / push_oam callbacks
  atm: remove AAL3/4 transport support
  net: dsa: sja1105: fix lastused timestamp in flower stats
  ...
appletalk: move the protocol out of tree 2026-06-16T21:37:06+00:00 Jakub Kicinski kuba@kernel.org 2026-06-15T22:29:35+00:00 8a398a0c189ead8bbce98f5be70b8ea0e30b21f8 AppleTalk has been removed in MacOS X 10.6 (Snow Leopard), in 2009, according to Wikipedia. We recently got a burst of AI generated fixes to this protocol which nobody is reviewing. Let AppleTalk follow AX.25 and hamradio out of the Linux tree. We we will maintain the code at: github.com/linux-netdev/mod-orphan for anyone interested in playing with it. Retain the uAPI for now. No strong reason, simply because I suspect keeping it will be less controversial. Acked-by: Stephen Hemminger <stephen@networkplumber.org> Link: https://patch.msgid.link/20260615222935.947233-3-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
AppleTalk has been removed in MacOS X 10.6 (Snow Leopard), in 2009,
according to Wikipedia. We recently got a burst of AI generated
fixes to this protocol which nobody is reviewing.

Let AppleTalk follow AX.25 and hamradio out of the Linux tree.
We we will maintain the code at: github.com/linux-netdev/mod-orphan
for anyone interested in playing with it.

Retain the uAPI for now. No strong reason, simply because I suspect
keeping it will be less controversial.

Acked-by: Stephen Hemminger <stephen@networkplumber.org>
Link: https://patch.msgid.link/20260615222935.947233-3-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
docs: mm: clarify that user_reserve_kbytes has no effect when overcommit_memory is set to 0 or 1 2026-06-04T21:45:08+00:00 Brian Masney bmasney@redhat.com 2026-05-28T13:45:10+00:00 a195cf013e98b02d3c129e2cccd7efa98aabf546 Looking at __vm_enough_memory() in mm/util.c, user_reserve_kbytes has no effect when overcommit_memory is set to 0 or 1. The documentation for overcommit_memory already references user_reserve_kbytes when the flag is set to 2. Let's go ahead and add a clarification to user_reserve_kbytes in vm.rst that it has no effect when overcommit_memory is set to 0 or 1. Link: https://lore.kernel.org/20260528-mm-clarify-docs-v1-1-aa88e83b4bfd@redhat.com Signed-off-by: Brian Masney <bmasney@redhat.com> Cc: David Hildenbrand <david@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Liam R. Howlett <liam@infradead.org> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Shuah Khan <skhan@linuxfoundation.org> Cc: Vlastimil Babka <vbabka@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> 
Looking at __vm_enough_memory() in mm/util.c, user_reserve_kbytes has no
effect when overcommit_memory is set to 0 or 1. The documentation for
overcommit_memory already references user_reserve_kbytes when the flag
is set to 2.

Let's go ahead and add a clarification to user_reserve_kbytes in vm.rst
that it has no effect when overcommit_memory is set to 0 or 1.

Link: https://lore.kernel.org/20260528-mm-clarify-docs-v1-1-aa88e83b4bfd@redhat.com
Signed-off-by: Brian Masney <bmasney@redhat.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
docs: sysctl/net: Remove ax25, netrom, rose entries 2026-05-25T20:31:44+00:00 Costa Shulyupin costa.shul@redhat.com 2026-05-15T18:01:57+00:00 d7391997ea9c93137bc855fd2b55392acbb7ef63 These networking subsystems were removed in commit dd8d4bc28ad7 ("net: remove ax25 and amateur radio (hamradio) subsystem"), but the sysctl directory table still listed them. Assisted-by: Claude:claude-opus-4-6 Signed-off-by: Costa Shulyupin <costa.shul@redhat.com> Acked-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net> Message-ID: <20260515180200.1490926-1-costa.shul@redhat.com> 
These networking subsystems were removed in commit dd8d4bc28ad7
("net: remove ax25 and amateur radio (hamradio) subsystem"),
but the sysctl directory table still listed them.

Assisted-by: Claude:claude-opus-4-6
Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20260515180200.1490926-1-costa.shul@redhat.com>
Merge tag 'mm-nonmm-stable-2026-04-15-04-20' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm 2026-04-17T03:11:56+00:00 Linus Torvalds torvalds@linux-foundation.org 2026-04-17T03:11:56+00:00 440d6635b20037bc9ad46b20817d7b61cef0fc1b Pull non-MM updates from Andrew Morton: - "pid: make sub-init creation retryable" (Oleg Nesterov) Make creation of init in a new namespace more robust by clearing away some historical cruft which is no longer needed. Also some documentation fixups - "selftests/fchmodat2: Error handling and general" (Mark Brown) Fix and a cleanup for the fchmodat2() syscall selftest - "lib: polynomial: Move to math/ and clean up" (Andy Shevchenko) - "hung_task: Provide runtime reset interface for hung task detector" (Aaron Tomlin) Give administrators the ability to zero out /proc/sys/kernel/hung_task_detect_count - "tools/getdelays: use the static UAPI headers from tools/include/uapi" (Thomas Weißschuh) Teach getdelays to use the in-kernel UAPI headers rather than the system-provided ones - "watchdog/hardlockup: Improvements to hardlockup" (Mayank Rungta) Several cleanups and fixups to the hardlockup detector code and its documentation - "lib/bch: fix undefined behavior from signed left-shifts" (Josh Law) A couple of small/theoretical fixes in the bch code - "ocfs2/dlm: fix two bugs in dlm_match_regions()" (Junrui Luo) - "cleanup the RAID5 XOR library" (Christoph Hellwig) A quite far-reaching cleanup to this code. I can't do better than to quote Christoph: "The XOR library used for the RAID5 parity is a bit of a mess right now. The main file sits in crypto/ despite not being cryptography and not using the crypto API, with the generic implementations sitting in include/asm-generic and the arch implementations sitting in an asm/ header in theory. The latter doesn't work for many cases, so architectures often build the code directly into the core kernel, or create another module for the architecture code. Change this to a single module in lib/ that also contains the architecture optimizations, similar to the library work Eric Biggers has done for the CRC and crypto libraries later. After that it changes to better calling conventions that allow for smarter architecture implementations (although none is contained here yet), and uses static_call to avoid indirection function call overhead" - "lib/list_sort: Clean up list_sort() scheduling workarounds" (Kuan-Wei Chiu) Clean up this library code by removing a hacky thing which was added for UBIFS, which UBIFS doesn't actually need - "Fix bugs in extract_iter_to_sg()" (Christian Ehrhardt) Fix a few bugs in the scatterlist code, add in-kernel tests for the now-fixed bugs and fix a leak in the test itself - "kdump: Enable LUKS-encrypted dump target support in ARM64 and PowerPC" (Coiby Xu) Enable support of the LUKS-encrypted device dump target on arm64 and powerpc - "ocfs2: consolidate extent list validation into block read callbacks" (Joseph Qi) Cleanup, simplify, and make more robust ocfs2's validation of extent list fields (Kernel test robot loves mounting corrupted fs images!) * tag 'mm-nonmm-stable-2026-04-15-04-20' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (127 commits) ocfs2: validate group add input before caching ocfs2: validate bg_bits during freefrag scan ocfs2: fix listxattr handling when the buffer is full doc: watchdog: fix typos etc update Sean's email address ocfs2: use get_random_u32() where appropriate ocfs2: split transactions in dio completion to avoid credit exhaustion ocfs2: remove redundant l_next_free_rec check in __ocfs2_find_path() ocfs2: validate extent block list fields during block read ocfs2: remove empty extent list check in ocfs2_dx_dir_lookup_rec() ocfs2: validate dx_root extent list fields during block read ocfs2: fix use-after-free in ocfs2_fault() when VM_FAULT_RETRY ocfs2: handle invalid dinode in ocfs2_group_extend .get_maintainer.ignore: add Askar ocfs2: validate bg_list extent bounds in discontig groups checkpatch: exclude forward declarations of const structs tools/accounting: handle truncated taskstats netlink messages taskstats: set version in TGID exit notifications ocfs2/heartbeat: fix slot mapping rollback leaks on error paths arm64,ppc64le/kdump: pass dm-crypt keys to kdump kernel ... 
Pull non-MM updates from Andrew Morton:

 - "pid: make sub-init creation retryable" (Oleg Nesterov)

   Make creation of init in a new namespace more robust by clearing away
   some historical cruft which is no longer needed. Also some
   documentation fixups

 - "selftests/fchmodat2: Error handling and general" (Mark Brown)

   Fix and a cleanup for the fchmodat2() syscall selftest

 - "lib: polynomial: Move to math/ and clean up" (Andy Shevchenko)

 - "hung_task: Provide runtime reset interface for hung task detector"
   (Aaron Tomlin)

   Give administrators the ability to zero out
   /proc/sys/kernel/hung_task_detect_count

 - "tools/getdelays: use the static UAPI headers from
   tools/include/uapi" (Thomas Weißschuh)

   Teach getdelays to use the in-kernel UAPI headers rather than the
   system-provided ones

 - "watchdog/hardlockup: Improvements to hardlockup" (Mayank Rungta)

   Several cleanups and fixups to the hardlockup detector code and its
   documentation

 - "lib/bch: fix undefined behavior from signed left-shifts" (Josh Law)

   A couple of small/theoretical fixes in the bch code

 - "ocfs2/dlm: fix two bugs in dlm_match_regions()" (Junrui Luo)

 - "cleanup the RAID5 XOR library" (Christoph Hellwig)

   A quite far-reaching cleanup to this code. I can't do better than to
   quote Christoph:

     "The XOR library used for the RAID5 parity is a bit of a mess right
      now. The main file sits in crypto/ despite not being cryptography
      and not using the crypto API, with the generic implementations
      sitting in include/asm-generic and the arch implementations
      sitting in an asm/ header in theory. The latter doesn't work for
      many cases, so architectures often build the code directly into
      the core kernel, or create another module for the architecture
      code.

      Change this to a single module in lib/ that also contains the
      architecture optimizations, similar to the library work Eric
      Biggers has done for the CRC and crypto libraries later. After
      that it changes to better calling conventions that allow for
      smarter architecture implementations (although none is contained
      here yet), and uses static_call to avoid indirection function call
      overhead"

 - "lib/list_sort: Clean up list_sort() scheduling workarounds"
   (Kuan-Wei Chiu)

   Clean up this library code by removing a hacky thing which was added
   for UBIFS, which UBIFS doesn't actually need

 - "Fix bugs in extract_iter_to_sg()" (Christian Ehrhardt)

   Fix a few bugs in the scatterlist code, add in-kernel tests for the
   now-fixed bugs and fix a leak in the test itself

 - "kdump: Enable LUKS-encrypted dump target support in ARM64 and
   PowerPC" (Coiby Xu)

   Enable support of the LUKS-encrypted device dump target on arm64 and
   powerpc

 - "ocfs2: consolidate extent list validation into block read callbacks"
   (Joseph Qi)

   Cleanup, simplify, and make more robust ocfs2's validation of extent
   list fields (Kernel test robot loves mounting corrupted fs images!)

* tag 'mm-nonmm-stable-2026-04-15-04-20' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (127 commits)
  ocfs2: validate group add input before caching
  ocfs2: validate bg_bits during freefrag scan
  ocfs2: fix listxattr handling when the buffer is full
  doc: watchdog: fix typos etc
  update Sean's email address
  ocfs2: use get_random_u32() where appropriate
  ocfs2: split transactions in dio completion to avoid credit exhaustion
  ocfs2: remove redundant l_next_free_rec check in __ocfs2_find_path()
  ocfs2: validate extent block list fields during block read
  ocfs2: remove empty extent list check in ocfs2_dx_dir_lookup_rec()
  ocfs2: validate dx_root extent list fields during block read
  ocfs2: fix use-after-free in ocfs2_fault() when VM_FAULT_RETRY
  ocfs2: handle invalid dinode in ocfs2_group_extend
  .get_maintainer.ignore: add Askar
  ocfs2: validate bg_list extent bounds in discontig groups
  checkpatch: exclude forward declarations of const structs
  tools/accounting: handle truncated taskstats netlink messages
  taskstats: set version in TGID exit notifications
  ocfs2/heartbeat: fix slot mapping rollback leaks on error paths
  arm64,ppc64le/kdump: pass dm-crypt keys to kdump kernel
  ...
Merge tag 'net-next-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 2026-04-15T01:36:10+00:00 Linus Torvalds torvalds@linux-foundation.org 2026-04-15T01:36:10+00:00 91a4855d6c03e770e42f17c798a36a3c46e63de2 Pull networking updates from Jakub Kicinski: "Core & protocols: - Support HW queue leasing, allowing containers to be granted access to HW queues for zero-copy operations and AF_XDP - Number of code moves to help the compiler with inlining. Avoid output arguments for returning drop reason where possible - Rework drop handling within qdiscs to include more metadata about the reason and dropping qdisc in the tracepoints - Remove the rtnl_lock use from IP Multicast Routing - Pack size information into the Rx Flow Steering table pointer itself. This allows making the table itself a flat array of u32s, thus making the table allocation size a power of two - Report TCP delayed ack timer information via socket diag - Add ip_local_port_step_width sysctl to allow distributing the randomly selected ports more evenly throughout the allowed space - Add support for per-route tunsrc in IPv6 segment routing - Start work of switching sockopt handling to iov_iter - Improve dynamic recvbuf sizing in MPTCP, limit burstiness and avoid buffer size drifting up - Support MSG_EOR in MPTCP - Add stp_mode attribute to the bridge driver for STP mode selection. This addresses concerns about call_usermodehelper() usage - Remove UDP-Lite support (as announced in 2023) - Remove support for building IPv6 as a module. Remove the now unnecessary function calling indirection Cross-tree stuff: - Move Michael MIC code from generic crypto into wireless, it's considered insecure but some WiFi networks still need it Netfilter: - Switch nft_fib_ipv6 module to no longer need temporary dst_entry object allocations by using fib6_lookup() + RCU. Florian W reports this gets us ~13% higher packet rate - Convert IPVS's global __ip_vs_mutex to per-net service_mutex and switch the service tables to be per-net. Convert some code that walks the service lists to use RCU instead of the service_mutex - Add more opinionated input validation to lower security exposure - Make IPVS hash tables to be per-netns and resizable Wireless: - Finished assoc frame encryption/EPPKE/802.1X-over-auth - Radar detection improvements - Add 6 GHz incumbent signal detection APIs - Multi-link support for FILS, probe response templates and client probing - New APIs and mac80211 support for NAN (Neighbor Aware Networking, aka Wi-Fi Aware) so less work must be in firmware Driver API: - Add numerical ID for devlink instances (to avoid having to create fake bus/device pairs just to have an ID). Support shared devlink instances which span multiple PFs - Add standard counters for reporting pause storm events (implement in mlx5 and fbnic) - Add configuration API for completion writeback buffering (implement in mana) - Support driver-initiated change of RSS context sizes - Support DPLL monitoring input frequency (implement in zl3073x) - Support per-port resources in devlink (implement in mlx5) Misc: - Expand the YAML spec for Netfilter Drivers - Software: - macvlan: support multicast rx for bridge ports with shared source MAC address - team: decouple receive and transmit enablement for IEEE 802.3ad LACP "independent control" - Ethernet high-speed NICs: - nVidia/Mellanox: - support high order pages in zero-copy mode (for payload coalescing) - support multiple packets in a page (for systems with 64kB pages) - Broadcom 25-400GE (bnxt): - implement XDP RSS hash metadata extraction - add software fallback for UDP GSO, lowering the IOMMU cost - Broadcom 800GE (bnge): - add link status and configuration handling - add various HW and SW statistics - Marvell/Cavium: - NPC HW block support for cn20k - Huawei (hinic3): - add mailbox / control queue - add rx VLAN offload - add driver info and link management - Ethernet NICs: - Marvell/Aquantia: - support reading SFP module info on some AQC100 cards - Realtek PCI (r8169): - add support for RTL8125cp - Realtek USB (r8152): - support for the RTL8157 5Gbit chip - add 2500baseT EEE status/configuration support - Ethernet NICs embedded and off-the-shelf IP: - Synopsys (stmmac): - cleanup and reorganize SerDes handling and PCS support - cleanup descriptor handling and per-platform data - cleanup and consolidate MDIO defines and handling - shrink driver memory use for internal structures - improve Tx IRQ coalescing - improve TCP segmentation handling - add support for Spacemit K3 - Cadence (macb): - support PHYs that have inband autoneg disabled with GEM - support IEEE 802.3az EEE - rework usrio capabilities and handling - AMD (xgbe): - improve power management for S0i3 - improve TX resilience for link-down handling - Virtual: - Google cloud vNIC: - support larger ring sizes in DQO-QPL mode - improve HW-GRO handling - support UDP GSO for DQO format - PCIe NTB: - support queue count configuration - Ethernet PHYs: - automatically disable PHY autonomous EEE if MAC is in charge - Broadcom: - add BCM84891/BCM84892 support - Micrel: - support for LAN9645X internal PHY - Realtek: - add RTL8224 pair order support - support PHY LEDs on RTL8211F-VD - support spread spectrum clocking (SSC) - Maxlinear: - add PHY-level statistics via ethtool - Ethernet switches: - Maxlinear (mxl862xx): - support for bridge offloading - support for VLANs - support driver statistics - Bluetooth: - large number of fixes and new device IDs - Mediatek: - support MT6639 (MT7927) - support MT7902 SDIO - WiFi: - Intel (iwlwifi): - UNII-9 and continuing UHR work - MediaTek (mt76): - mt7996/mt7925 MLO fixes/improvements - mt7996 NPU support (HW eth/wifi traffic offload) - Qualcomm (ath12k): - monitor mode support on IPQ5332 - basic hwmon temperature reporting - support IPQ5424 - Realtek: - add USB RX aggregation to improve performance - add USB TX flow control by tracking in-flight URBs - Cellular: - IPA v5.2 support" * tag 'net-next-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1561 commits) net: pse-pd: fix kernel-doc function name for pse_control_find_by_id() wireguard: device: use exit_rtnl callback instead of manual rtnl_lock in pre_exit wireguard: allowedips: remove redundant space tools: ynl: add sample for wireguard wireguard: allowedips: Use kfree_rcu() instead of call_rcu() MAINTAINERS: Add netkit selftest files selftests/net: Add additional test coverage in nk_qlease selftests/net: Split netdevsim tests from HW tests in nk_qlease tools/ynl: Make YnlFamily closeable as a context manager net: airoha: Add missing PPE configurations in airoha_ppe_hw_init() net: airoha: Fix VIP configuration for AN7583 SoC net: caif: clear client service pointer on teardown net: strparser: fix skb_head leak in strp_abort_strp() net: usb: cdc-phonet: fix skb frags[] overflow in rx_complete() selftests/bpf: add test for xdp_master_redirect with bond not up net, bpf: fix null-ptr-deref in xdp_master_redirect() for down master net: airoha: Remove PCE_MC_EN_MASK bit in REG_FE_PCE_CFG configuration sctp: disable BH before calling udp_tunnel_xmit_skb() sctp: fix missing encap_port propagation for GSO fragments net: airoha: Rely on net_device pointer in ETS callbacks ... 
Pull networking updates from Jakub Kicinski:
 "Core & protocols:

   - Support HW queue leasing, allowing containers to be granted access
     to HW queues for zero-copy operations and AF_XDP

   - Number of code moves to help the compiler with inlining. Avoid
     output arguments for returning drop reason where possible

   - Rework drop handling within qdiscs to include more metadata about
     the reason and dropping qdisc in the tracepoints

   - Remove the rtnl_lock use from IP Multicast Routing

   - Pack size information into the Rx Flow Steering table pointer
     itself. This allows making the table itself a flat array of u32s,
     thus making the table allocation size a power of two

   - Report TCP delayed ack timer information via socket diag

   - Add ip_local_port_step_width sysctl to allow distributing the
     randomly selected ports more evenly throughout the allowed space

   - Add support for per-route tunsrc in IPv6 segment routing

   - Start work of switching sockopt handling to iov_iter

   - Improve dynamic recvbuf sizing in MPTCP, limit burstiness and avoid
     buffer size drifting up

   - Support MSG_EOR in MPTCP

   - Add stp_mode attribute to the bridge driver for STP mode selection.
     This addresses concerns about call_usermodehelper() usage

   - Remove UDP-Lite support (as announced in 2023)

   - Remove support for building IPv6 as a module. Remove the now
     unnecessary function calling indirection

  Cross-tree stuff:

   - Move Michael MIC code from generic crypto into wireless, it's
     considered insecure but some WiFi networks still need it

  Netfilter:

   - Switch nft_fib_ipv6 module to no longer need temporary dst_entry
     object allocations by using fib6_lookup() + RCU.

     Florian W reports this gets us ~13% higher packet rate

   - Convert IPVS's global __ip_vs_mutex to per-net service_mutex and
     switch the service tables to be per-net. Convert some code that
     walks the service lists to use RCU instead of the service_mutex

   - Add more opinionated input validation to lower security exposure

   - Make IPVS hash tables to be per-netns and resizable

  Wireless:

   - Finished assoc frame encryption/EPPKE/802.1X-over-auth

   - Radar detection improvements

   - Add 6 GHz incumbent signal detection APIs

   - Multi-link support for FILS, probe response templates and client
     probing

   - New APIs and mac80211 support for NAN (Neighbor Aware Networking,
     aka Wi-Fi Aware) so less work must be in firmware

  Driver API:

   - Add numerical ID for devlink instances (to avoid having to create
     fake bus/device pairs just to have an ID). Support shared devlink
     instances which span multiple PFs

   - Add standard counters for reporting pause storm events (implement
     in mlx5 and fbnic)

   - Add configuration API for completion writeback buffering (implement
     in mana)

   - Support driver-initiated change of RSS context sizes

   - Support DPLL monitoring input frequency (implement in zl3073x)

   - Support per-port resources in devlink (implement in mlx5)

  Misc:

   - Expand the YAML spec for Netfilter

  Drivers

   - Software:
      - macvlan: support multicast rx for bridge ports with shared
        source MAC address
      - team: decouple receive and transmit enablement for IEEE 802.3ad
        LACP "independent control"

   - Ethernet high-speed NICs:
      - nVidia/Mellanox:
         - support high order pages in zero-copy mode (for payload
           coalescing)
         - support multiple packets in a page (for systems with 64kB
           pages)
      - Broadcom 25-400GE (bnxt):
         - implement XDP RSS hash metadata extraction
         - add software fallback for UDP GSO, lowering the IOMMU cost
      - Broadcom 800GE (bnge):
         - add link status and configuration handling
         - add various HW and SW statistics
      - Marvell/Cavium:
         - NPC HW block support for cn20k
      - Huawei (hinic3):
         - add mailbox / control queue
         - add rx VLAN offload
         - add driver info and link management

   - Ethernet NICs:
      - Marvell/Aquantia:
         - support reading SFP module info on some AQC100 cards
      - Realtek PCI (r8169):
         - add support for RTL8125cp
      - Realtek USB (r8152):
         - support for the RTL8157 5Gbit chip
         - add 2500baseT EEE status/configuration support

   - Ethernet NICs embedded and off-the-shelf IP:
      - Synopsys (stmmac):
         - cleanup and reorganize SerDes handling and PCS support
         - cleanup descriptor handling and per-platform data
         - cleanup and consolidate MDIO defines and handling
         - shrink driver memory use for internal structures
         - improve Tx IRQ coalescing
         - improve TCP segmentation handling
         - add support for Spacemit K3
      - Cadence (macb):
         - support PHYs that have inband autoneg disabled with GEM
         - support IEEE 802.3az EEE
         - rework usrio capabilities and handling
      - AMD (xgbe):
         - improve power management for S0i3
         - improve TX resilience for link-down handling

   - Virtual:
      - Google cloud vNIC:
         - support larger ring sizes in DQO-QPL mode
         - improve HW-GRO handling
         - support UDP GSO for DQO format
      - PCIe NTB:
         - support queue count configuration

   - Ethernet PHYs:
      - automatically disable PHY autonomous EEE if MAC is in charge
      - Broadcom:
         - add BCM84891/BCM84892 support
      - Micrel:
         - support for LAN9645X internal PHY
      - Realtek:
         - add RTL8224 pair order support
         - support PHY LEDs on RTL8211F-VD
         - support spread spectrum clocking (SSC)
      - Maxlinear:
         - add PHY-level statistics via ethtool

   - Ethernet switches:
      - Maxlinear (mxl862xx):
         - support for bridge offloading
         - support for VLANs
         - support driver statistics

   - Bluetooth:
      - large number of fixes and new device IDs
      - Mediatek:
         - support MT6639 (MT7927)
         - support MT7902 SDIO

   - WiFi:
      - Intel (iwlwifi):
         - UNII-9 and continuing UHR work
      - MediaTek (mt76):
         - mt7996/mt7925 MLO fixes/improvements
         - mt7996 NPU support (HW eth/wifi traffic offload)
      - Qualcomm (ath12k):
         - monitor mode support on IPQ5332
         - basic hwmon temperature reporting
         - support IPQ5424
      - Realtek:
         - add USB RX aggregation to improve performance
         - add USB TX flow control by tracking in-flight URBs

   - Cellular:
      - IPA v5.2 support"

* tag 'net-next-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1561 commits)
  net: pse-pd: fix kernel-doc function name for pse_control_find_by_id()
  wireguard: device: use exit_rtnl callback instead of manual rtnl_lock in pre_exit
  wireguard: allowedips: remove redundant space
  tools: ynl: add sample for wireguard
  wireguard: allowedips: Use kfree_rcu() instead of call_rcu()
  MAINTAINERS: Add netkit selftest files
  selftests/net: Add additional test coverage in nk_qlease
  selftests/net: Split netdevsim tests from HW tests in nk_qlease
  tools/ynl: Make YnlFamily closeable as a context manager
  net: airoha: Add missing PPE configurations in airoha_ppe_hw_init()
  net: airoha: Fix VIP configuration for AN7583 SoC
  net: caif: clear client service pointer on teardown
  net: strparser: fix skb_head leak in strp_abort_strp()
  net: usb: cdc-phonet: fix skb frags[] overflow in rx_complete()
  selftests/bpf: add test for xdp_master_redirect with bond not up
  net, bpf: fix null-ptr-deref in xdp_master_redirect() for down master
  net: airoha: Remove PCE_MC_EN_MASK bit in REG_FE_PCE_CFG configuration
  sctp: disable BH before calling udp_tunnel_xmit_skb()
  sctp: fix missing encap_port propagation for GSO fragments
  net: airoha: Rely on net_device pointer in ETS callbacks
  ...
Merge tag 'docs-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/docs/linux 2026-04-14T15:47:08+00:00 Linus Torvalds torvalds@linux-foundation.org 2026-04-14T15:47:08+00:00 5181afcdf99527dd92a88f80fc4d0d8013e1b510 Pull documentation updates from Jonathan Corbet: "A busier cycle than I had expected for docs, including: - Translations: some overdue updates to the Japanese translations, Chinese translations for some of the Rust documentation, and the beginnings of a Portuguese translation. - New documents covering CPU isolation, managed interrupts, debugging Python gbb scripts, and more. - More tooling work from Mauro, reducing docs-build warnings, adding self tests, improving man-page output, bringing in a proper C tokenizer to replace (some of) the mess of kernel-doc regexes, and more. - Update and synchronize changes.rst and scripts/ver_linux, and put both into alphabetical order. ... and a long list of documentation updates, typo fixes, and general improvements" * tag 'docs-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/docs/linux: (162 commits) Documentation: core-api: real-time: correct spelling doc: Add CPU Isolation documentation Documentation: Add managed interrupts Documentation: seq_file: drop 2.6 reference docs/zh_CN: update rust/index.rst translation docs/zh_CN: update rust/quick-start.rst translation docs/zh_CN: update rust/coding-guidelines.rst translation docs/zh_CN: update rust/arch-support.rst translation docs/zh_CN: sync process/2.Process.rst with English version docs/zh_CN: fix an inconsistent statement in dev-tools/testing-overview tracing: Documentation: Update histogram-design.rst for fn() handling docs: sysctl: Add documentation for /proc/sys/xen/ Docs: hid: intel-ish-hid: make long URL usable Documentation/kernel-parameters: fix architecture alignment for pt, nopt, and nobypass sched/doc: Update yield_task description in sched-design-CFS Documentation/rtla: Convert links to RST format docs: fix typos and duplicated words across documentation docs: fix typo in zoran driver documentation docs: add an Assisted-by mention to submitting-patches.rst Revert "scripts/checkpatch: add Assisted-by: tag validation" ... 
Pull documentation updates from Jonathan Corbet:
 "A busier cycle than I had expected for docs, including:

   - Translations: some overdue updates to the Japanese translations,
     Chinese translations for some of the Rust documentation, and the
     beginnings of a Portuguese translation.

   - New documents covering CPU isolation, managed interrupts, debugging
     Python gbb scripts, and more.

   - More tooling work from Mauro, reducing docs-build warnings, adding
     self tests, improving man-page output, bringing in a proper C
     tokenizer to replace (some of) the mess of kernel-doc regexes, and
     more.

   - Update and synchronize changes.rst and scripts/ver_linux, and put
     both into alphabetical order.

  ... and a long list of documentation updates, typo fixes, and general
  improvements"

* tag 'docs-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/docs/linux: (162 commits)
  Documentation: core-api: real-time: correct spelling
  doc: Add CPU Isolation documentation
  Documentation: Add managed interrupts
  Documentation: seq_file: drop 2.6 reference
  docs/zh_CN: update rust/index.rst translation
  docs/zh_CN: update rust/quick-start.rst translation
  docs/zh_CN: update rust/coding-guidelines.rst translation
  docs/zh_CN: update rust/arch-support.rst translation
  docs/zh_CN: sync process/2.Process.rst with English version
  docs/zh_CN: fix an inconsistent statement in dev-tools/testing-overview
  tracing: Documentation: Update histogram-design.rst for fn() handling
  docs: sysctl: Add documentation for /proc/sys/xen/
  Docs: hid: intel-ish-hid: make long URL usable
  Documentation/kernel-parameters: fix architecture alignment for pt, nopt, and nobypass
  sched/doc: Update yield_task description in sched-design-CFS
  Documentation/rtla: Convert links to RST format
  docs: fix typos and duplicated words across documentation
  docs: fix typo in zoran driver documentation
  docs: add an Assisted-by mention to submitting-patches.rst
  Revert "scripts/checkpatch: add Assisted-by: tag validation"
  ...
docs: sysctl: Add documentation for /proc/sys/xen/ 2026-04-09T14:44:31+00:00 Shubham Chakraborty chakrabortyshubham66@gmail.com 2026-03-04T15:04:19+00:00 136799e52c4d3ebf14705ffffb69b8c7ae6f03ae Add documentation for the Xen hypervisor sysctl controls in /proc/sys/xen/balloon/. Documents the hotplug_unpopulated tunable (available when CONFIG_XEN_BALLOON_MEMORY_HOTPLUG is enabled) which controls whether unpopulated memory regions are automatically hotplugged when the Xen balloon driver needs to reclaim memory. The documentation is based on source code analysis of drivers/xen/balloon.c. Signed-off-by: Shubham Chakraborty <chakrabortyshubham66@gmail.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net> Message-ID: <20260304150419.16738-1-chakrabortyshubham66@gmail.com> 
Add documentation for the Xen hypervisor sysctl controls in
/proc/sys/xen/balloon/.

Documents the hotplug_unpopulated tunable (available when
CONFIG_XEN_BALLOON_MEMORY_HOTPLUG is enabled) which controls
whether unpopulated memory regions are automatically hotplugged
when the Xen balloon driver needs to reclaim memory.

The documentation is based on source code analysis of
drivers/xen/balloon.c.

Signed-off-by: Shubham Chakraborty <chakrabortyshubham66@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20260304150419.16738-1-chakrabortyshubham66@gmail.com>
hung_task: enable runtime reset of hung_task_detect_count 2026-03-28T04:19:40+00:00 Aaron Tomlin atomlin@atomlin.com 2026-03-03T20:30:30+00:00 49085e1b70f898695b63594ff559f5a243589b83 Currently, the hung_task_detect_count sysctl provides a cumulative count of hung tasks since boot. In long-running, high-availability environments, this counter may lose its utility if it cannot be reset once an incident has been resolved. Furthermore, the previous implementation relied upon implicit ordering, which could not strictly guarantee that diagnostic metadata published by one CPU was visible to the panic logic on another. This patch introduces the capability to reset the detection count by writing "0" to the hung_task_detect_count sysctl. The proc_handler logic has been updated to validate this input and atomically reset the counter. The synchronisation of sysctl_hung_task_detect_count relies upon a transactional model to ensure the integrity of the detection counter against concurrent resets from userspace. The application of atomic_long_read_acquire() and atomic_long_cmpxchg_release() is correct and provides the following guarantees: 1. Prevention of Load-Store Reordering via Acquire Semantics By utilising atomic_long_read_acquire() to snapshot the counter before initiating the task traversal, we establish a strict memory barrier. This prevents the compiler or hardware from reordering the initial load to a point later in the scan. Without this "acquire" barrier, a delayed load could potentially read a "0" value resulting from a userspace reset that occurred mid-scan. This would lead to the subsequent cmpxchg succeeding erroneously, thereby overwriting the user's reset with stale increment data. 2. Atomicity of the "Commit" Phase via Release Semantics The atomic_long_cmpxchg_release() serves as the transaction's commit point. The "release" barrier ensures that all diagnostic recordings and task-state observations made during the scan are globally visible before the counter is incremented. 3. Race Condition Resolution This pairing effectively detects any "out-of-band" reset of the counter. If sysctl_hung_task_detect_count is modified via the procfs interface during the scan, the final cmpxchg will detect the discrepancy between the current value and the "acquire" snapshot. Consequently, the update will fail, ensuring that a reset command from the administrator is prioritised over a scan that may have been invalidated by that very reset. Link: https://lkml.kernel.org/r/20260303203031.4097316-3-atomlin@atomlin.com Signed-off-by: Aaron Tomlin <atomlin@atomlin.com> Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Reviewed-by: Joel Granados <joel.granados@kernel.org> Reviewed-by: Petr Mladek <pmladek@suse.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Lance Yang <lance.yang@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> 
Currently, the hung_task_detect_count sysctl provides a cumulative count
of hung tasks since boot.  In long-running, high-availability
environments, this counter may lose its utility if it cannot be reset once
an incident has been resolved.  Furthermore, the previous implementation
relied upon implicit ordering, which could not strictly guarantee that
diagnostic metadata published by one CPU was visible to the panic logic on
another.

This patch introduces the capability to reset the detection count by
writing "0" to the hung_task_detect_count sysctl.  The proc_handler logic
has been updated to validate this input and atomically reset the counter.

The synchronisation of sysctl_hung_task_detect_count relies upon a
transactional model to ensure the integrity of the detection counter
against concurrent resets from userspace.  The application of
atomic_long_read_acquire() and atomic_long_cmpxchg_release() is correct
and provides the following guarantees:

    1. Prevention of Load-Store Reordering via Acquire Semantics By
       utilising atomic_long_read_acquire() to snapshot the counter
       before initiating the task traversal, we establish a strict
       memory barrier. This prevents the compiler or hardware from
       reordering the initial load to a point later in the scan. Without
       this "acquire" barrier, a delayed load could potentially read a
       "0" value resulting from a userspace reset that occurred
       mid-scan. This would lead to the subsequent cmpxchg succeeding
       erroneously, thereby overwriting the user's reset with stale
       increment data.

    2. Atomicity of the "Commit" Phase via Release Semantics The
       atomic_long_cmpxchg_release() serves as the transaction's commit
       point. The "release" barrier ensures that all diagnostic
       recordings and task-state observations made during the scan are
       globally visible before the counter is incremented.

    3. Race Condition Resolution This pairing effectively detects any
       "out-of-band" reset of the counter. If
       sysctl_hung_task_detect_count is modified via the procfs
       interface during the scan, the final cmpxchg will detect the
       discrepancy between the current value and the "acquire" snapshot.
       Consequently, the update will fail, ensuring that a reset command
       from the administrator is prioritised over a scan that may have
       been invalidated by that very reset.

Link: https://lkml.kernel.org/r/20260303203031.4097316-3-atomlin@atomlin.com
Signed-off-by: Aaron Tomlin <atomlin@atomlin.com>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Joel Granados <joel.granados@kernel.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Lance Yang <lance.yang@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>