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2026-05-13macsec: use rcu_work to defer RX SA crypto cleanup out of softirqJinliang Zheng
crypto_free_aead() can internally invoke vunmap() (e.g. via dma_free_attrs() in hardware crypto drivers such as hisi_sec2). vunmap() must not be called from softirq context, but free_rxsa() is an RCU callback that runs in softirq, leading to a kernel crash: vunmap+0x4c/0x70 __iommu_dma_free+0xd0/0x138 dma_free_attrs+0xf4/0x100 sec_aead_exit+0x64/0xb8 [hisi_sec2] crypto_destroy_tfm+0x98/0x110 free_rxsa+0x28/0x50 [macsec] rcu_do_batch+0x184/0x460 rcu_core+0xf4/0x1f8 handle_softirqs+0x118/0x330 Use rcu_work to defer the cleanup to a workqueue. rcu_work dispatches the worker asynchronously after the RCU grace period, so no thread blocks waiting, and concurrent releases of multiple SAs naturally share the same grace period. Fixes: c09440f7dcb3 ("macsec: introduce IEEE 802.1AE driver") Signed-off-by: Jinliang Zheng <alexjlzheng@tencent.com> Reviewed-by: Sabrina Dubroca <sd@queasysnail.net> Link: https://patch.msgid.link/20260511153102.2640368-3-alexjlzheng@tencent.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-05-13macsec: introduce dedicated workqueue for SA crypto cleanupJinliang Zheng
Introduce a dedicated ordered workqueue, macsec_wq, which will be used by subsequent patches to defer SA crypto cleanup (crypto_free_aead and related teardown) out of softirq context. Using a dedicated workqueue instead of system_wq allows macsec_exit() to drain exactly the work items belonging to this module via destroy_workqueue(), without interfering with unrelated work items on system_wq or causing unexpected delays elsewhere. rcu_barrier() in macsec_exit() ensures all in-flight rcu_work callbacks have enqueued their work items before destroy_workqueue() drains and destroys the queue, making the two-step teardown correct and complete. The same sequence is kept in the error path of macsec_init() as a precaution, to mirror macsec_exit() and stay safe if work ever becomes queueable before this point in the future. While at it, rename the error labels in macsec_init() from the resource-named style (rtnl:, notifier:, wq:) to the err_xxx: style (err_rtnl:, err_notifier:, err_destroy_wq:) to align with the broader kernel convention. Signed-off-by: Jinliang Zheng <alexjlzheng@tencent.com> Reviewed-by: Sabrina Dubroca <sd@queasysnail.net> Link: https://patch.msgid.link/20260511153102.2640368-2-alexjlzheng@tencent.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-05-13net: net_failover: Fix the deadlock in slave registerFaicker Mo
There is netdev_lock_ops() before the NETDEV_REGISTER notifier in register_netdevice(), so use the non-locking functions in net_failover_slave_register(). failover_slave_register() in failover_existing_slave_register() adds lock and unlock ops too. Call Trace: <TASK> __schedule+0x30d/0x7a0 schedule+0x27/0x90 schedule_preempt_disabled+0x15/0x30 __mutex_lock.constprop.0+0x538/0x9e0 __mutex_lock_slowpath+0x13/0x20 mutex_lock+0x3b/0x50 dev_set_mtu+0x40/0xe0 net_failover_slave_register+0x24/0x280 failover_slave_register+0x103/0x1b0 failover_event+0x15e/0x210 ? dropmon_net_event+0xac/0xe0 notifier_call_chain+0x5e/0xe0 raw_notifier_call_chain+0x16/0x30 call_netdevice_notifiers_info+0x52/0xa0 register_netdevice+0x5f4/0x7c0 register_netdev+0x1e/0x40 _mlx5e_probe+0xe2/0x370 [mlx5_core] mlx5e_probe+0x59/0x70 [mlx5_core] ? __pfx_mlx5e_probe+0x10/0x10 [mlx5_core] Fixes: 4c975fd70002 ("net: hold instance lock during NETDEV_REGISTER/UP") Signed-off-by: Faicker Mo <faicker.mo@gmail.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-05-14Merge tag 'drm-intel-fixes-2026-05-13' of ↵Dave Airlie
https://gitlab.freedesktop.org/drm/i915/kernel into drm-fixes - Skip __i915_request_skip() for already signaled requests (Sebastian Brzezinka) - Fix VSC dynamic range signaling for RGB formats [dp] (Chaitanya Kumar Borah) Signed-off-by: Dave Airlie <airlied@redhat.com> From: Tvrtko Ursulin <tursulin@igalia.com> Link: https://patch.msgid.link/agSVZmNC_qV4G6jQ@linux
2026-05-13Merge branch 'bpf-maximum-combined-stack-depth'Alexei Starovoitov
Paul Chaignon says: ==================== bpf: Maximum combined stack depth This patchset dumps the maximum combined stack depth in verifier logs and parses it in veristat. Changes in v3: - Increment spec_cnt field in veristat for new MAX_STACK id (AI bot). Changes in v2: - Remove unnecessary max_stack_depth assignment (Eduard). - Fix and test incorrect handling of private stacks. - Add veristat metric (Eduard). ==================== Link: https://patch.msgid.link/cover.1778700777.git.paul.chaignon@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-05-13veristat: Report max stack depthPaul Chaignon
This patch adds a new "Max stack depth" field to the set of gathered statistics. This field reports the maximum combined stack depth compared to the 512 bytes limit. It is null for rejected programs. Suggested-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Paul Chaignon <paul.chaignon@gmail.com> Link: https://lore.kernel.org/r/a27ed8f336669152c4b1b05e920aee4438e3e2b3.1778700777.git.paul.chaignon@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-05-13selftests/bpf: Test reported max stack depthPaul Chaignon
This patch tests the maximum stack depth reporting in verifier logs, with a couple special cases covered: fastcall, private stacks (main subprog & callee), and rounding up to 16 bytes. For that last one, we need to skip the test when JIT compilation is disabled as the rounding is then to 32 bytes. Signed-off-by: Paul Chaignon <paul.chaignon@gmail.com> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/r/075d22efd4338385a92f13b7817025cc3f04ec60.1778700777.git.paul.chaignon@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-05-13bpf: Report maximum combined stack depthPaul Chaignon
We've hit the 512 bytes limit on stack depth a few times in Cilium recently. As a result, we started reporting in CI our current maximum stack depth across all configurations for each BPF program. Unfortunately, that is not trivial to compute in userspace. The verifier reports the stack depths of individual subprogs at the end of the logs. However the maximum combined stack depth also depends on the callgraph of those subprogs (the max combined stack depth is the height of the callgraph weighted by per-subprog stack depths). We can compute a callgraph in userspace from the loaded instructions, but it often doesn't match the verifier's own callgraph because of dead code elimination. Our current approach relies on dumping the BPF_LOG_LEVEL2 logs, but this feels overkill considering the verifier already has the information we need. The patch lets the verifier dump the maximum combined stack depth in the logs, on the same line as the per-subprog stack depths: stack depth 16+256 max 272 The per-subprog stack depths and the new max stack depth are not directly comparable. The former is sometimes updated during fixups, while the latter is not. As a result, even with a single subprog, we may end up with two slightly different values. The aim of the new max value is to be closest to what is actually enforced by the verifier. Signed-off-by: Paul Chaignon <paul.chaignon@gmail.com> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/r/d3d23a0410f87f116f3bbaa98a815dbae113bda2.1778700777.git.paul.chaignon@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-05-13MAINTAINERS: update atlantic driver maintainerSukhdeep Singh
Igor Russkikh and Egor Pomozov have left Marvell. Take over maintenance of the atlantic driver and its PTP subsystem. Signed-off-by: Sukhdeep Singh <sukhdeeps@marvell.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-05-13Merge branch 'netpoll-move-out-netconsole-specific-functions'Jakub Kicinski
Breno Leitao says: ==================== netpoll: move out netconsole-specific functions netpoll and netconsole were created together and their code has been intermixed in net/core/netpoll.c for decades. The result is that netpoll exposes two send-side interfaces: * a generic "give me an sk_buff" path used by every stacked-device driver (bonding, team, vlan, bridge, macvlan, dsa), * a second path that takes raw bytes and builds a UDP/IP/Ethernet packet -- exclusively for netconsole. The packet builder, an skb pool allocator, and several netconsole-specific helpers all live next to the generic plumbing even though no other consumer ever touches them. Worse, every netpoll user pays for that overlap: struct netpoll carries an skb_pool and a refill work_struct that only netconsole's find_skb() ever reads from, and net-core has to review unrelated changes (TTL, hop limit, IP ID generation, source MAC selection, pool sizing) just because they happen to be coded inside netpoll. This is a waste of memory for something useless. This series splits the netconsole-specific code out: * netpoll_send_udp() and its private helpers (push_ipv6, push_ipv4, push_eth, push_udp, netpoll_udp_checksum, find_skb) move into drivers/net/netconsole.c, leaving netpoll with a single skb-only send interface that is the same for every user. The moves are one function per patch for reviewability; helpers are temporarily EXPORT_SYMBOL_GPL'd while netpoll_send_udp() is still in netpoll calling them, then those exports are dropped together once netpoll_send_udp() itself moves. The only new permanent export is zap_completion_queue(), needed because find_skb() still drains the per-CPU TX completion queue before allocating. struct netpoll is unchanged in this series; making the pool itself netconsole-private (and reclaiming the skb_pool / refill_wq fields for the rest of netpoll's users) is the natural follow-up, once this patchset lands. ==================== Link: https://patch.msgid.link/20260512-netconsole_split-v2-0-1191d14ad66d@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-05-13netconsole: move find_skb() from netpollBreno Leitao
find_skb() is the netconsole-specific entry into the netpoll skb pool: every other netpoll consumer (bonding, team, vlan, bridge, macvlan, dsa) builds its own sk_buff and never touches the pool. With netpoll_send_udp() (its only caller) now living in netconsole, find_skb() can join it. Move find_skb() into drivers/net/netconsole.c as a file-static helper, drop EXPORT_SYMBOL_GPL(find_skb) and remove its prototype from include/linux/netpoll.h. find_skb() drains TX completions via netpoll_zap_completion_queue(), which is already exported in the NETDEV_INTERNAL namespace, so netconsole picks up MODULE_IMPORT_NS("NETDEV_INTERNAL") to consume it. The skb pool's lifecycle (np->skb_pool, np->refill_wq, refill_skbs(), refill_skbs_work_handler(), skb_pool_flush()) stays in netpoll: it is initialised in __netpoll_setup() and torn down in __netpoll_cleanup(), both of which remain netpoll's responsibility. The refill work queued via schedule_work(&np->refill_wq) from the moved find_skb() runs refill_skbs_work_handler() in netpoll without any further plumbing. This is pure code motion: the function body is unchanged and its sole caller (netpoll_send_udp(), already moved by an earlier patch) keeps invoking it the same way. Pre-existing concerns about find_skb() running from NMI/printk context (zap_completion_queue() re-entry, skb_pool spinlocks, GFP_ATOMIC allocation, fallback skb sizing vs. MAX_SKB_SIZE, PREEMPT_RT semantics of __kfree_skb()) are inherited as-is and are not addressed here; they predate this series and are out of scope. Fixing them is left for follow-up work. Signed-off-by: Breno Leitao <leitao@debian.org> Link: https://patch.msgid.link/20260512-netconsole_split-v2-9-1191d14ad66d@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-05-13netpoll: rename and export netpoll_zap_completion_queue()Breno Leitao
zap_completion_queue() drains the per-CPU softnet completion queue. Rename it with the netpoll_ prefix shared by the rest of the subsystem's public API, and promote it from file-static to EXPORT_SYMBOL_NS_GPL in the NETDEV_INTERNAL namespace so the upcoming netconsole-side find_skb() can call it once the function moves out. A forward declaration is added to include/linux/netpoll.h, and the old file-static forward declaration is dropped. No functional change. Suggested-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Breno Leitao <leitao@debian.org> Link: https://patch.msgid.link/20260512-netconsole_split-v2-8-1191d14ad66d@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-05-13netconsole: move netpoll_udp_checksum() from netpollBreno Leitao
netpoll_udp_checksum() computes the UDP checksum for netconsole's packets. Move it into drivers/net/netconsole.c as a file-static helper; drop its EXPORT_SYMBOL_GPL and remove the prototype from include/linux/netpoll.h. This was the last csum_ipv6_magic() consumer in net/core/netpoll.c, so drop the now-stale <net/ip6_checksum.h> include there. Pull it into netconsole.c so the moved code keeps building. It was also the last udp_hdr() consumer in net/core/netpoll.c. The file no longer needs anything from <net/udp.h> (the UDP socket-layer helpers); MAX_SKB_SIZE only needs struct udphdr, which is provided by the lighter <linux/udp.h>. Swap the include accordingly. Signed-off-by: Breno Leitao <leitao@debian.org> Link: https://patch.msgid.link/20260512-netconsole_split-v2-7-1191d14ad66d@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-05-13netconsole: move push_udp() from netpollBreno Leitao
push_udp() builds the UDP header (and triggers the checksum) for netconsole's UDP packets. Move it into drivers/net/netconsole.c as a file-static helper; drop its EXPORT_SYMBOL_GPL and remove the prototype from include/linux/netpoll.h. Signed-off-by: Breno Leitao <leitao@debian.org> Link: https://patch.msgid.link/20260512-netconsole_split-v2-6-1191d14ad66d@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-05-13netconsole: move push_eth() from netpollBreno Leitao
push_eth() builds the Ethernet header for netconsole's UDP packets. Move it into drivers/net/netconsole.c as a file-static helper; drop its EXPORT_SYMBOL_GPL and remove the prototype from include/linux/netpoll.h. Signed-off-by: Breno Leitao <leitao@debian.org> Link: https://patch.msgid.link/20260512-netconsole_split-v2-5-1191d14ad66d@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-05-13netconsole: move push_ipv4() from netpollBreno Leitao
push_ipv4() builds the IPv4 header for netconsole's UDP packets. Move it into drivers/net/netconsole.c as a file-static helper; drop its EXPORT_SYMBOL_GPL and remove the prototype from include/linux/netpoll.h. put_unaligned() is no longer used in net/core/netpoll.c, so drop the now-stale <linux/unaligned.h> include from there. Pull it into netconsole.c so the moved code keeps building. Signed-off-by: Breno Leitao <leitao@debian.org> Link: https://patch.msgid.link/20260512-netconsole_split-v2-4-1191d14ad66d@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-05-13netconsole: move push_ipv6() from netpollBreno Leitao
push_ipv6() builds the IPv6 header for netconsole's UDP packets. Its only caller, netpoll_send_udp(), now lives in netconsole, so the helper can move there as a file-static function. Drop its EXPORT_SYMBOL_GPL and remove the prototype from include/linux/netpoll.h. Signed-off-by: Breno Leitao <leitao@debian.org> Link: https://patch.msgid.link/20260512-netconsole_split-v2-3-1191d14ad66d@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-05-13netconsole: move netpoll_send_udp() from netpollBreno Leitao
Move netpoll_send_udp() from net/core/netpoll.c into drivers/net/netconsole.c as a static helper, drop EXPORT_SYMBOL(), and remove the prototype from include/linux/netpoll.h. netconsole was the only in-tree caller of this entry point. Every other netpoll consumer (bonding, team, vlan, bridge, macvlan, dsa) already builds its own sk_buff and hands it to netpoll_send_skb(), so the netpoll send-side interface is now skb-only. The helpers it depends on (find_skb(), push_ipv6(), push_ipv4(), push_udp(), push_eth(), netpoll_udp_checksum()) were exposed in the previous patches and stay in net/core/netpoll.c for now. Subsequent patches move each of them into netconsole one at a time and drop the corresponding EXPORT_SYMBOL_GPL. Pull <linux/ip.h>, <linux/ipv6.h> and <linux/udp.h> into netconsole.c so the moved code can name the header structures. Signed-off-by: Breno Leitao <leitao@debian.org> Link: https://patch.msgid.link/20260512-netconsole_split-v2-2-1191d14ad66d@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-05-13netpoll: expose UDP packet builder helpers for netconsoleBreno Leitao
Promote each from file-static to EXPORT_SYMBOL_GPL and forward- declare them in include/linux/netpoll.h so netconsole can call them once netpoll_send_udp() moves out. These exports are kept until the end of the series, when al of them move into netconsole. No functional change. Signed-off-by: Breno Leitao <leitao@debian.org> Link: https://patch.msgid.link/20260512-netconsole_split-v2-1-1191d14ad66d@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-05-13riscv: cfi: reduce shadow stack size limit from 4GB to 2GBZong Li
Follow the ARM64 GCS (Guarded Control Stack) implementation approach by reducing the shadow stack size allocation from min(RLIMIT_STACK, 4GB) to min(RLIMIT_STACK/2, 2GB). See commit 506496bcbb42 ("arm64/gcs: Ensure that new threads have a GCS") Rationale: 1. Shadow stacks only store return addresses (8 bytes per entry), not local variables, function parameters, or saved registers. A 2GB shadow stack is far more than sufficient for any practical application, even with extremely deep recursion. Using half the size maintains adequate margin while being more resource-efficient. 2. On memory-constrained systems (e.g., platforms with only 4GB of physical memory, which is a common configuration), allocating 4GB of virtual address space for shadow stack per process/thread can lead to virtual memory allocation failures when the overcommit mode is set to OVERCOMMIT_GUESS or OVERCOMMIT_NEVER: Error: "__vm_enough_memory: not enough memory for the allocation" This reduces virtual address space consumption by 50% while maintaining more than adequate space for return address storage. Signed-off-by: Zong Li <zong.li@sifive.com> Link: https://patch.msgid.link/20260428024105.645162-1-zong.li@sifive.com [pjw@kernel.org: clean up patch description] Signed-off-by: Paul Walmsley <pjw@kernel.org>
2026-05-13net: usb: pegasus: replace simple_strtoul with kstrtouintSajal Gupta
simple_strtoul() is deprecated as it has no error checking. Replace it with kstrtouint() which returns an error code on invalid input, and add appropriate error handling. Also add a NULL check before parsing flags, since strsep() can set id to NULL if the input has fewer tokens than expected. Preserve the original behavior for a trailing colon by checking *id before parsing flags, so an empty string results in flags = 0 rather than an error. Signed-off-by: Sajal Gupta <sajal2005gupta@gmail.com> Link: https://patch.msgid.link/20260509095518.2640-1-sajal2005gupta@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-05-13ipvlan: use netif_receive_skb() in ipvlan_process_multicast()Eric Dumazet
ipvlan_process_multicast() runs from process context, there is no risk of stack overflow if we call netif_receive_skb() instead of netif_rx(). This avoids some overhead adding/removing skbs to/from a per-cpu backlog and raising/processing NET_RX softirqs. Signed-off-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20260512042019.3300975-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-05-13selftests/tc-testing: Add QFQ/CBS qlen underflow testVictor Nogueira
Since CBS was not calling reset for its child qdisc, there are scenarios where it could cause an underflow on its parent's qlen/backlog. When the parent is QFQ, a null-ptr deref could occur. Add a test case that reproduces the underflow followed by a null-ptr deref scenario. Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: Victor Nogueira <victor@mojatatu.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-05-13net/sched: sch_cbs: Call qdisc_reset for child qdiscJamal Hadi Salim
During a reset, CBS is not calling reset on its child qdisc, which might cause qlen/backlog accounting issues. For example, if we have CBS with a QFQ parent and a netem child with delay, we can create a scenario where the parent's qlen underflows. QFQ, specifically, uses qlen to check whether it should deference a pointer, so this scenario may cause a null-ptr deref in QFQ: [ 43.875639][ T319] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000009: 0000 [#1] SMP KASAN NOPTI [ 43.876124][ T319] KASAN: null-ptr-deref in range [0x0000000000000048-0x000000000000004f] [ 43.876417][ T319] CPU: 10 UID: 0 PID: 319 Comm: ping Not tainted 7.0.0-13039-ge728258debd5 #773 PREEMPT(full) [ 43.876751][ T319] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 [ 43.876949][ T319] RIP: 0010:qfq_dequeue+0x35c/0x1650 [ 43.877123][ T319] Code: 00 fc ff df 80 3c 02 00 0f 85 17 0e 00 00 4c 8d 73 48 48 89 9d b8 02 00 00 48 b8 00 00 00 00 00 fc ff df 4c 89 f2 48 c1 ea 03 <80> 3c 02 00 0f 85 76 0c 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8b [ 43.877648][ T319] RSP: 0018:ffff8881017ef4f0 EFLAGS: 00010216 [ 43.877845][ T319] RAX: dffffc0000000000 RBX: 0000000000000000 RCX: dffffc0000000000 [ 43.878073][ T319] RDX: 0000000000000009 RSI: 0000000c40000000 RDI: ffff88810eef02b0 [ 43.878306][ T319] RBP: ffff88810eef0000 R08: ffff88810eef0280 R09: 1ffff1102120fd63 [ 43.878523][ T319] R10: 1ffff1102120fd66 R11: 1ffff1102120fd67 R12: 0000000c40000000 [ 43.878742][ T319] R13: ffff88810eef02b8 R14: 0000000000000048 R15: 0000000020000000 [ 43.878959][ T319] FS: 00007f9c51c47c40(0000) GS:ffff88817a0be000(0000) knlGS:0000000000000000 [ 43.879214][ T319] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 43.879403][ T319] CR2: 000055e69a2230a8 CR3: 000000010c07a000 CR4: 0000000000750ef0 [ 43.879621][ T319] PKRU: 55555554 [ 43.879735][ T319] Call Trace: [ 43.879844][ T319] <TASK> [ 43.879924][ T319] __qdisc_run+0x169/0x1900 [ 43.880075][ T319] ? dev_qdisc_enqueue+0x8b/0x210 [ 43.880222][ T319] __dev_queue_xmit+0x2346/0x37a0 [ 43.880376][ T319] ? register_lock_class+0x3f/0x800 [ 43.880531][ T319] ? srso_alias_return_thunk+0x5/0xfbef5 [ 43.880684][ T319] ? __pfx___dev_queue_xmit+0x10/0x10 [ 43.880834][ T319] ? srso_alias_return_thunk+0x5/0xfbef5 [ 43.880977][ T319] ? __lock_acquire+0x819/0x1df0 [ 43.881124][ T319] ? srso_alias_return_thunk+0x5/0xfbef5 [ 43.881275][ T319] ? srso_alias_return_thunk+0x5/0xfbef5 [ 43.881418][ T319] ? __asan_memcpy+0x3c/0x60 [ 43.881563][ T319] ? srso_alias_return_thunk+0x5/0xfbef5 [ 43.881708][ T319] ? eth_header+0x165/0x1a0 [ 43.881853][ T319] ? lockdep_hardirqs_on_prepare+0xdb/0x1a0 [ 43.882031][ T319] ? srso_alias_return_thunk+0x5/0xfbef5 [ 43.882174][ T319] ? neigh_resolve_output+0x3cc/0x7e0 [ 43.882325][ T319] ? srso_alias_return_thunk+0x5/0xfbef5 [ 43.882471][ T319] ip_finish_output2+0x6b6/0x1e10 Fix this by calling qdisc_reset for CBS' child qdisc. Sashiko caught an issue which could result in a null ptr deref if qdisc_create_dflt() is invoked on an unitialised cbs qdisc which is exposed by this patch. We add an early return if the qdisc is null to address this. This is a similar approach used by two other fixes[1][2]. The proper fix for this specific issue elucidated by sashiko is to remove the call to qdisc_reset when qdisc_create_dflt fails. Since the dflt qdisc isn't attached anywhere yet at that point, calling the reset callback doesn't make much sense (and as stated has been a source of two other bugs). We plan on submitting this fix in a later patch. [1] https://lore.kernel.org/netdev/20221018063201.306474-2-shaozhengchao@huawei.com/ [2] https://lore.kernel.org/netdev/20221018063201.306474-4-shaozhengchao@huawei.com/ Fixes: 585d763af09c ("net/sched: Introduce Credit Based Shaper (CBS) qdisc") Reported-by: Junyoung Jang <graypanda.inzag@gmail.com> Tested-by: Junyoung Jang <graypanda.inzag@gmail.com> Tested-by: Victor Nogueira <victor@mojatatu.com> Acked-by: Vinicius Costa Gomes <vinicius.gomes@intel.com> Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-05-13Merge branch ↵Jakub Kicinski
'tun-tap-vhost-net-apply-qdisc-backpressure-on-full-ptr_ring-to-reduce-tx-drops' Simon Schippers says: ==================== tun/tap & vhost-net: apply qdisc backpressure on full ptr_ring to reduce TX drops This patch series deals with tun/tap & vhost-net which drop incoming SKBs whenever their internal ptr_ring buffer is full. Instead, with this patch series, the associated netdev queue is stopped - but only when a qdisc is attached. If no qdisc is present the existing behavior is preserved. The XDP transmit path is not affected. This patch series touches tun/tap and vhost-net, as they share common logic and must be updated together. Modifying only one of them would break the other. By applying proper backpressure, this change allows the connected qdisc to operate correctly, as reported in [1], and significantly improves performance in real-world scenarios, as demonstrated in our paper [2]. For example, we observed a 36% TCP throughput improvement for an OpenVPN connection between Germany and the USA. Synthetic pktgen benchmarks indicate a slight regression, and packet loss is reduced to near zero. Pktgen benchmarks are provided per commit, with the final commit showing the overall performance. [1] Link: https://unix.stackexchange.com/questions/762935/traffic-shaping-ineffective-on-tun-device [2] Link: https://cni.etit.tu-dortmund.de/storages/cni-etit/r/Research/Publications/2025/Gebauer_2025_VTCFall/Gebauer_VTCFall2025_AuthorsVersion.pdf ==================== Link: https://patch.msgid.link/20260510151529.43895-1-simon.schippers@tu-dortmund.de Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-05-13tun/tap & vhost-net: avoid ptr_ring tail-drop when a qdisc is presentSimon Schippers
This commit prevents tail-drop when a qdisc is present and the ptr_ring becomes full. Once the ring reaches capacity after a produce attempt, the netdev queue is stopped instead of dropping subsequent packets. If no qdisc is present, the previous tail-drop behavior is preserved. If producing an entry fails anyway due to a race, tun_net_xmit() drops the packet. Such races are expected because LLTX is enabled and the transmit path operates without the usual locking. The __tun_wake_queue() function of the consumer races with the producer for waking/stopping the netdev queue, which could result in a stalled queue. Therefore, an smp_mb__after_atomic() is introduced that pairs with the smp_mb() of the consumer. It follows the principle of store buffering described in tools/memory-model/Documentation/recipes.txt: - The producer in tun_net_xmit() first sets __QUEUE_STATE_DRV_XOFF, followed by an smp_mb__after_atomic() (= smp_mb()), and then reads the ring with __ptr_ring_check_produce(). - The consumer in __tun_wake_queue() first writes zero to the ring in __ptr_ring_consume(), followed by an smp_mb(), and then reads the queue status with netif_tx_queue_stopped(). => Following the aforementioned principle, it is impossible for the producer to see a full ring (and therefore not wake the queue on the re-check) while the consumer simultaneously fails to see a stopped queue (and therefore also does not wake it). Benchmarks: The benchmarks show a slight regression in raw transmission performance when using two sending threads. Packet loss also occurs only in the two-thread sending case; no packet loss was observed with a single sending thread. Test setup: AMD Ryzen 5 5600X at 4.3 GHz, 3200 MHz RAM, isolated QEMU threads; Average over 50 runs @ 100,000,000 packets. SRSO and spectre v2 mitigations disabled. Note for tap+vhost-net: XDP drop program active in VM -> ~2.5x faster; slower for tap due to more syscalls (high utilization of entry_SYSRETQ_unsafe_stack in perf) +--------------------------+--------------+----------------+----------+ | 1 thread | Stock | Patched with | diff | | sending | | fq_codel qdisc | | +------------+-------------+--------------+----------------+----------+ | TAP | Received | 1.132 Mpps | 1.123 Mpps | -0.8% | | +-------------+--------------+----------------+----------+ | | Lost/s | 3.765 Mpps | 0 pps | | +------------+-------------+--------------+----------------+----------+ | TAP | Received | 3.857 Mpps | 3.901 Mpps | +1.1% | | +-------------+--------------+----------------+----------+ | +vhost-net | Lost/s | 0.802 Mpps | 0 pps | | +------------+-------------+--------------+----------------+----------+ +--------------------------+--------------+----------------+----------+ | 2 threads | Stock | Patched with | diff | | sending | | fq_codel qdisc | | +------------+-------------+--------------+----------------+----------+ | TAP | Received | 1.115 Mpps | 1.081 Mpps | -3.0% | | +-------------+--------------+----------------+----------+ | | Lost/s | 8.490 Mpps | 391 pps | | +------------+-------------+--------------+----------------+----------+ | TAP | Received | 3.664 Mpps | 3.555 Mpps | -3.0% | | +-------------+--------------+----------------+----------+ | +vhost-net | Lost/s | 5.330 Mpps | 938 pps | | +------------+-------------+--------------+----------------+----------+ Co-developed-by: Tim Gebauer <tim.gebauer@tu-dortmund.de> Signed-off-by: Tim Gebauer <tim.gebauer@tu-dortmund.de> Signed-off-by: Simon Schippers <simon.schippers@tu-dortmund.de> Acked-by: Michael S. Tsirkin <mst@redhat.com> Link: https://patch.msgid.link/20260510151529.43895-5-simon.schippers@tu-dortmund.de Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-05-13ptr_ring: move free-space check into separate helperSimon Schippers
This patch moves the check for available free space for a new entry into a separate function. Existing callers that only check for a non-zero return value are unaffected; __ptr_ring_produce() now returns -EINVAL for a zero-size ring and -ENOSPC when full, whereas before both cases returned -ENOSPC. The new helper allows callers to determine in advance whether subsequent __ptr_ring_produce() calls will succeed. This information can, for example, be used to temporarily stop producing until __ptr_ring_check_produce() indicates that space is available again. Co-developed-by: Tim Gebauer <tim.gebauer@tu-dortmund.de> Signed-off-by: Tim Gebauer <tim.gebauer@tu-dortmund.de> Signed-off-by: Simon Schippers <simon.schippers@tu-dortmund.de> Acked-by: Michael S. Tsirkin <mst@redhat.com> Link: https://patch.msgid.link/20260510151529.43895-4-simon.schippers@tu-dortmund.de Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-05-13vhost-net: wake queue of tun/tap after ptr_ring consumeSimon Schippers
Add tun_wake_queue() to tun.c and export it for use by vhost-net. The function validates that the file belongs to a tun/tap device and that the tfile exists, dereferences the tun_struct under RCU, and delegates to __tun_wake_queue(). vhost_net_buf_produce() now calls tun_wake_queue() after a successful batched consume of the ring to allow the netdev subqueue to be woken up. The point is to allow the queue to be stopped when it gets full, which is required for traffic shaping - implemented by the following "avoid ptr_ring tail-drop when a qdisc is present". Without the corresponding queue stopping, this patch alone causes no throughput regression for a tap+vhost-net setup sending to a qemu VM: 3.857 Mpps to 3.891 Mpps. Details: AMD Ryzen 5 5600X at 4.3 GHz, 3200 MHz RAM, isolated QEMU threads, XDP drop program active in VM, pktgen sender; Avg over 50 runs @ 100,000,000 packets. SRSO and spectre v2 mitigations disabled. Co-developed-by: Tim Gebauer <tim.gebauer@tu-dortmund.de> Signed-off-by: Tim Gebauer <tim.gebauer@tu-dortmund.de> Signed-off-by: Simon Schippers <simon.schippers@tu-dortmund.de> Acked-by: Michael S. Tsirkin <mst@redhat.com> Link: https://patch.msgid.link/20260510151529.43895-3-simon.schippers@tu-dortmund.de Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-05-13tun/tap: add ptr_ring consume helper with netdev queue wakeupSimon Schippers
Introduce tun_ring_consume() that wraps ptr_ring_consume() and calls __tun_wake_queue(). The latter wakes the stopped netdev subqueue once half of the ring capacity has been consumed, tracked via the new cons_cnt field in tun_file. As a safety net, the queue is also woken on the last consumed entry if it leaves the ring empty. The point is to allow the queue to be stopped when it gets full, which is required for traffic shaping - implemented by the following "avoid ptr_ring tail-drop when a qdisc is present". Some implementation details: - tun_ring_recv() replaces ptr_ring_consume() with tun_ring_consume() to properly wake the queue. - __tun_detach() locks the tx_ring.consumer_lock to avoid races with the consumer on the queue_index. - The ptr_ring_consume() call in tun_queue_purge() is not replaced with tun_ring_consume(). Instead, within the same tx_ring.consumer_lock in __tun_detach(), the netdev queue is woken for the ntfile taking it over, to avoid a possible stall. This does not matter for tun_detach_all(), as it is called during device teardown and no tfile takes over any queue. - Reset cons_cnt in tun_attach() so the half-ring wake threshold is valid for the new ring size after ptr_ring_resize(). - tun_queue_resize() wakes all queues after resizing with the proper tx_ring.consumer_lock and resets the cons_cnt to avoid a possible stale queue. - The aforementioned upcoming patch explains the pairing of the smp_mb() of __tun_wake_queue(). Without the corresponding queue stopping, this patch alone causes no regression for a tap setup sending to a qemu VM: 1.132 Mpps to 1.134 Mpps. Details: AMD Ryzen 5 5600X at 4.3 GHz, 3200 MHz RAM, isolated QEMU threads, pktgen sender; Avg over 50 runs @ 100,000,000 packets; SRSO and spectre v2 mitigations disabled. Co-developed-by: Tim Gebauer <tim.gebauer@tu-dortmund.de> Signed-off-by: Tim Gebauer <tim.gebauer@tu-dortmund.de> Signed-off-by: Simon Schippers <simon.schippers@tu-dortmund.de> Acked-by: Michael S. Tsirkin <mst@redhat.com> Link: https://patch.msgid.link/20260510151529.43895-2-simon.schippers@tu-dortmund.de Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-05-14ASoC: sdw_utils: add ES9356 in codec_info_listZhang Yi
Add ES9356 in codec_info_list Signed-off-by: Zhang Yi <zhangyi@everest-semi.com> Link: https://patch.msgid.link/20260513031554.5422-3-zhangyi@everest-semi.com Signed-off-by: Mark Brown <broonie@kernel.org>
2026-05-14ASoC: sdw_utils: add soc_sdw_es9356Zhang Yi
Add a utility program for handling ES9356 in the universal machine driver Signed-off-by: Zhang Yi <zhangyi@everest-semi.com> Link: https://patch.msgid.link/20260513031554.5422-2-zhangyi@everest-semi.com Signed-off-by: Mark Brown <broonie@kernel.org>
2026-05-14ASoC: sdw_utils: Remove dead code in asoc_sdw_ti_add_tac5xx2_routes()Niranjan H Y
Remove unnecessary checks for scnprintf() return values in asoc_sdw_ti_add_tac5xx2_routes(). The function scnprintf() never returns negative values and cannot return zero given the format strings used ("%s SPK_L" and "%s SPK_R"). The existing length validation at line 110 already ensures that name_prefix won't cause buffer overflow, and scnprintf() guarantees null-termination even in case of truncation. Fixes: e812de61e9a0 ("ASoC: sdw_utils: TI amp utility for tac5xx2 family") Reported-by: Dan Carpenter <error27@gmail.com> Closes: https://lore.kernel.org/linux-sound/agF8GBcHYUaGJbXY@stanley.mountain/ Signed-off-by: Niranjan H Y <niranjan.hy@ti.com> Link: https://patch.msgid.link/20260513015542.2420-1-niranjan.hy@ti.com Signed-off-by: Mark Brown <broonie@kernel.org>
2026-05-14ASoC: sdw_utils: Check speaker component string allocationCássio Gabriel
devm_kasprintf() can fail while building the temporary speaker component string. If that happens, spk_components is set to NULL, but the current code can still pass it to strlen() on a later loop iteration or after the loop when appending the speaker component list to card->components. Use NULL to represent the initial "no speaker components" state, and return -ENOMEM immediately if building spk_components fails. Fixes: 0f60ecffbfe3 ("ASoC: sdw_utils: generate combined spk components string") Signed-off-by: Cássio Gabriel <cassiogabrielcontato@gmail.com> Link: https://patch.msgid.link/20260512-asoc-sdw-utils-spk-components-alloc-v1-1-c9bbd6d2e123@gmail.com Signed-off-by: Mark Brown <broonie@kernel.org>
2026-05-13mm/memory: fix spurious warning when unmapping device-private/exclusive pagesAlistair Popple
Device private and exclusive entries are only supported for anonymous folios. This condition is tested in __migrate_device_pages() and make_device_exclusive() using folio_test_anon(). However the unmap path tests this assumption using vma_is_anonymous(). This is wrong because whilst anonymous VMAs can only contain folios where folio_test_anon() is true the opposite relation does not hold. A folio for which folio_test_anon() is true does not imply vma_is_anonymous() is true. Such a condition can occur if for example a folio is part of a private filebacked mapping. In this case vma_is_anonymous() is false as the mapping is filebacked, but folio_test_anon() may be true, thus permitting devices to migrate the folio to device private memory. This can lead to the following spurious warnings during process teardown: [ 772.737706] ------------[ cut here ]------------ [ 772.739201] WARNING: mm/memory.c:1754 at unmap_page_range.cold+0x26/0x18a, CPU#17: hmm-tests/2041 [ 772.742050] Modules linked in: test_hmm nvidia_uvm(O) nvidia(O) [ 772.743959] CPU: 17 UID: 0 PID: 2041 Comm: hmm-tests Tainted: G W O 7.0.0+ #387 PREEMPT(full) [ 772.747104] Tainted: [W]=WARN, [O]=OOT_MODULE [ 772.748509] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014 [ 772.752117] RIP: 0010:unmap_page_range.cold+0x26/0x18a [ 772.753780] Code: 7e fe ff ff 48 89 4c 24 78 4c 89 44 24 38 e8 f2 ff b1 00 48 8b 4c 24 78 4c 8b 44 24 38 48 8b 44 24 18 48 83 78 48 00 74 04 90 <0f> 0b 90 48 89 ca b8 ff ff 37 00 48 c1 ea 03 48 c1 e0 2a 80 3c 02 [ 772.759602] RSP: 0018:ffff888112607550 EFLAGS: 00010286 [ 772.761310] RAX: ffff88811bbf4dc0 RBX: dffffc0000000000 RCX: ffffea03e9bfffd8 [ 772.763583] RDX: 1ffff1102377e9c1 RSI: 0000000000000008 RDI: ffff88811bbf4e08 [ 772.765914] RBP: 0000000000000006 R08: ffff8881059f7448 R09: ffffed10224c0e68 [ 772.768184] R10: ffff888112607347 R11: 0000000000000001 R12: 0000000000000001 [ 772.770461] R13: ffffea03e9bfffc0 R14: ffff888112607908 R15: ffffea03e9bfffc0 [ 772.772782] FS: 00007f327caa2780(0000) GS:ffff888427b7d000(0000) knlGS:0000000000000000 [ 772.775328] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 772.777187] CR2: 00007f327ca89000 CR3: 00000001994d5000 CR4: 00000000000006f0 [ 772.779135] Call Trace: [ 772.779792] <TASK> [ 772.780317] ? dmirror_interval_invalidate+0x1a3/0x290 [test_hmm] [ 772.781873] ? vm_normal_page_pud+0x2b0/0x2b0 [ 772.782992] ? __rwlock_init+0x150/0x150 [ 772.784006] ? lock_release+0x216/0x2b0 [ 772.785008] ? __mmu_notifier_invalidate_range_start+0x505/0x6e0 [ 772.786522] ? lock_release+0x216/0x2b0 [ 772.787498] ? unmap_single_vma+0xb6/0x210 [ 772.788573] unmap_vmas+0x27d/0x520 [ 772.789506] ? unmap_single_vma+0x210/0x210 [ 772.790607] ? mas_update_gap.part.0+0x620/0x620 [ 772.791834] unmap_region+0x19e/0x350 [ 772.792769] ? remove_vma+0x130/0x130 [ 772.793684] ? mas_alloc_nodes+0x1f2/0x300 [ 772.794730] vms_complete_munmap_vmas+0x8c1/0xe20 [ 772.795926] ? unmap_region+0x350/0x350 [ 772.796917] do_vmi_align_munmap+0x36a/0x4e0 [ 772.798018] ? lock_release+0x216/0x2b0 [ 772.799024] ? vma_shrink+0x620/0x620 [ 772.799983] do_vmi_munmap+0x150/0x2c0 [ 772.800939] __vm_munmap+0x161/0x2c0 [ 772.801872] ? expand_downwards+0xd60/0xd60 [ 772.802948] ? clockevents_program_event+0x1ef/0x540 [ 772.804217] ? lock_release+0x216/0x2b0 [ 772.805158] __x64_sys_munmap+0x59/0x80 [ 772.805776] do_syscall_64+0xfc/0x670 [ 772.806336] ? irqentry_exit+0xda/0x580 [ 772.806976] entry_SYSCALL_64_after_hwframe+0x4b/0x53 [ 772.807772] RIP: 0033:0x7f327cbb2717 [ 772.808323] Code: 73 01 c3 48 8b 0d f9 76 0d 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 0b 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d c9 76 0d 00 f7 d8 64 89 01 48 [ 772.811337] RSP: 002b:00007ffde7f57d38 EFLAGS: 00000202 ORIG_RAX: 000000000000000b [ 772.812564] RAX: ffffffffffffffda RBX: 00007f327cc9c000 RCX: 00007f327cbb2717 [ 772.813733] RDX: 0000000000000000 RSI: 0000000000400000 RDI: 00007f327c289000 [ 772.814867] RBP: 0000000000421360 R08: 000000000000001a R09: 0000000000000000 [ 772.815991] R10: 0000000000000003 R11: 0000000000000202 R12: 00007ffde7f57d74 [ 772.817121] R13: 00007f327c689010 R14: 0000000000100000 R15: 00007f327c289000 [ 772.818272] </TASK> [ 772.818614] irq event stamp: 0 [ 772.819159] hardirqs last enabled at (0): [<0000000000000000>] 0x0 [ 772.820174] hardirqs last disabled at (0): [<ffffffff82a57ab3>] copy_process+0x19f3/0x6440 [ 772.821511] softirqs last enabled at (0): [<ffffffff82a57b00>] copy_process+0x1a40/0x6440 [ 772.822869] softirqs last disabled at (0): [<0000000000000000>] 0x0 [ 772.823871] ---[ end trace 0000000000000000 ]--- Fix this by using the same check for folio_test_anon() in zap_nonpresent_ptes(). Also add a hmm-test case for this. Link: https://lore.kernel.org/20260501065116.2057242-1-apopple@nvidia.com Fixes: 999dad824c39 ("mm/shmem: persist uffd-wp bit across zapping for file-backed") Signed-off-by: Alistair Popple <apopple@nvidia.com> Reported-by: Arsen Arsenović <aarsenovic@baylibre.com> Reviewed-by: Balbir Singh <balbirs@nvidia.com> Cc: David Hildenbrand <david@kernel.org> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Leon Romanovsky <leon@kernel.org> Cc: Liam R. Howlett <liam@infradead.org> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Peter Xu <peterx@redhat.com> Cc: Matthew Brost <matthew.brost@intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Shuah Khan <shuah@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com> Cc: Vlastimil Babka <vbabka@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-05-13mm: fix __vm_normal_page() to handle missing support for ↵David Hildenbrand (Arm)
pmd_special()/pud_special() On x86 32-bit with THP enabled, zap_huge_pmd() is seen to generate a "WARNING: mm/memory.c:735 at __vm_normal_page+0x6a/0x7d", from the VM_WARN_ON_ONCE(is_zero_pfn(pfn) || is_huge_zero_pfn(pfn)); followed by "BUG: Bad rss-counter state"s, then later "BUG: Bad page state"s when reclaim gets to call shrink_huge_zero_folio_scan(). It's as if the _PAGE_SPECIAL bit never got set in the huge_zero pmd: and indeed, whereas pte_special() and pte_mkspecial() are subject to a dedicated CONFIG_ARCH_HAS_PTE_SPECIAL, pmd_special() and pmd_mkspecial() are subject to CONFIG_ARCH_SUPPORTS_PMD_PFNMAP, which is never enabled on any 32-bit architecture. While the problem was exposed through commit d80a9cb1a64a ("mm/huge_memory: add and use normal_or_softleaf_folio_pmd()"), it was an oversight in commit af38538801c6 ("mm/memory: factor out common code from vm_normal_page_*()") and would result in other problems: * huge zero folio accounted in smaps, pagemap (PAGE_IS_FILE) and numamaps as file-backed THP * folio_walk_start() returning the folio even without FW_ZEROPAGE set. Callers seem to tolerate that, though. ... and triggering the VM_WARN_ON_ONE(), although never reported so far. To fix it, teach vm_normal_page_pmd()/vm_normal_page_pud() to consider whether pmd_special/pud_special is actually implemented. Link: https://lore.kernel.org/20260430-pmd_special-v1-1-dbcbcfd72c20@kernel.org Fixes: af38538801c6 ("mm/memory: factor out common code from vm_normal_page_*()") Signed-off-by: David Hildenbrand (Arm) <david@kernel.org> Reported-by: Hugh Dickins <hughd@google.com> Closes: https://lore.kernel.org/r/74a75b59-2e13-3985-ee99-d5521f39df2a@google.com Reported-by: Bibo Mao <maobibo@loongson.cn> Closes: https://lore.kernel.org/r/20260430041121.2839350-1-maobibo@loongson.cn Debugged-by: Hugh Dickins <hughd@google.com> Reviewed-by: Lance Yang <lance.yang@linux.dev> Tested-by: Bibo Mao <maobibo@loongson.cn> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Reviewed-by: Lorenzo Stoakes <ljs@kernel.org> Cc: Liam R. Howlett <liam@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-05-13drivers/base/memory: fix memory block reference leak in poison accountingMuchun Song
memblk_nr_poison_inc() and memblk_nr_poison_sub() look up a memory block via find_memory_block_by_id(), which acquires a reference to the memory block device. Both helpers use the returned memory block without dropping that reference, leaking the device reference on each successful lookup. Drop the reference after updating nr_hwpoison. Link: https://lore.kernel.org/20260428085219.1316047-3-songmuchun@bytedance.com Fixes: 5033091de814 ("mm/hwpoison: introduce per-memory_block hwpoison counter") Signed-off-by: Muchun Song <songmuchun@bytedance.com> Reviewed-by: Miaohe Lin <linmiaohe@huawei.com> Acked-by: Oscar Salvador <osalvador@suse.de> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Cc: Danilo Krummrich <dakr@kernel.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Huang, Ying" <huang.ying.caritas@gmail.com> Cc: Naoya Horiguchi <nao.horiguchi@gmail.com> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-05-13mm/memory_hotplug: fix memory block reference leak on removeMuchun Song
Patch series "mm: Fix memory block leaks and locking", v2. This series fixes two memory block device reference leaks and one locking issue around the per-memory_block hwpoison counter. This patch (of 2): remove_memory_blocks_and_altmaps() looks up each memory block with find_memory_block(), which acquires a reference to the memory block device. That reference is never dropped on this path, resulting in a leaked device reference when removing memory blocks and their altmaps. Drop the reference after retrieving mem->altmap and clearing mem->altmap, before removing the memory block device. Link: https://lore.kernel.org/20260428085219.1316047-1-songmuchun@bytedance.com Link: https://lore.kernel.org/20260428085219.1316047-2-songmuchun@bytedance.com Fixes: 6b8f0798b85a ("mm/memory_hotplug: split memmap_on_memory requests across memblocks") Signed-off-by: Muchun Song <songmuchun@bytedance.com> Acked-by: Oscar Salvador <osalvador@suse.de> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Cc: Danilo Krummrich <dakr@kernel.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Huang, Ying" <huang.ying.caritas@gmail.com> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Naoya Horiguchi <nao.horiguchi@gmail.com> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-05-13lib: kunit_iov_iter: fix test fail on powerpcChristian A. Ehrhardt
Increase buffer size to accommodate machines with 64K PAGE_SIZE. Link: https://lore.kernel.org/20260421070707.992873-1-lk@c--e.de Fixes: 0913b7554726 ("lib: kunit_iov_iter: add tests for extract_iter_to_sg") Signed-off-by: Christian A. Ehrhardt <lk@c--e.de> Reported-by: David Gow <davidgow@google.com> Closes: https://lore.kernel.org/34a81ec2-af84-465d-9b5e-7bb5bf01680f@davidgow.net Tested-by: David Gow <davidgow@google.com> Tested-by: Josh Law <joshlaw48@gmail.com> Reviewed-by: Josh Law <joshlaw48@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-05-13mm/page_alloc: fix initialization of tags of the huge zero folio with ↵David Hildenbrand (Arm)
init_on_free __GFP_ZEROTAGS semantics are currently a bit weird, but effectively this flag is only ever set alongside __GFP_ZERO and __GFP_SKIP_KASAN. If we run with init_on_free, we will zero out pages during __free_pages_prepare(), to skip zeroing on the allocation path. However, when allocating with __GFP_ZEROTAG set, post_alloc_hook() will consequently not only skip clearing page content, but also skip clearing tag memory. Not clearing tags through __GFP_ZEROTAGS is irrelevant for most pages that will get mapped to user space through set_pte_at() later: set_pte_at() and friends will detect that the tags have not been initialized yet (PG_mte_tagged not set), and initialize them. However, for the huge zero folio, which will be mapped through a PMD marked as special, this initialization will not be performed, ending up exposing whatever tags were still set for the pages. The docs (Documentation/arch/arm64/memory-tagging-extension.rst) state that allocation tags are set to 0 when a page is first mapped to user space. That no longer holds with the huge zero folio when init_on_free is enabled. Fix it by decoupling __GFP_ZEROTAGS from __GFP_ZERO, passing to tag_clear_highpages() whether we want to also clear page content. Invert the meaning of the tag_clear_highpages() return value to have clearer semantics. Reproduced with the huge zero folio by modifying the check_buffer_fill arm64/mte selftest to use a 2 MiB area, after making sure that pages have a non-0 tag set when freeing (note that, during boot, we will not actually initialize tags, but only set KASAN_TAG_KERNEL in the page flags). $ ./check_buffer_fill 1..20 ... not ok 17 Check initial tags with private mapping, sync error mode and mmap memory not ok 18 Check initial tags with private mapping, sync error mode and mmap/mprotect memory ... This code needs more cleanups; we'll tackle that next, like decoupling __GFP_ZEROTAGS from __GFP_SKIP_KASAN. [akpm@linux-foundation.org: s/__GPF_ZERO/__GFP_ZERO/, per David] Link: https://lore.kernel.org/20260421-zerotags-v2-1-05cb1035482e@kernel.org Fixes: adfb6609c680 ("mm/huge_memory: initialise the tags of the huge zero folio") Signed-off-by: David Hildenbrand (Arm) <david@kernel.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Tested-by: Lance Yang <lance.yang@linux.dev> Cc: Brendan Jackman <jackmanb@google.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Liam Howlett <liam@infradead.org> Cc: Lorenzo Stoakes (Oracle) <ljs@kernel.org> Cc: Mark Brown <broonie@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Will Deacon <will@kernel.org> Cc: Zi Yan <ziy@nvidia.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-05-13MAINTAINERS: add kexec@ list to LIVE UPDATE ENTRYMike Rapoport (Microsoft)
Link: https://lore.kernel.org/20260428124833.1903302-3-rppt@kernel.org Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Acked-by: Pasha Tatashin <pasha.tatashin@soleen.com> Acked-by: Baoquan He <baoquan.he@linux.dev> Cc: Dave Young <ruirui.yang@linux.dev> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Pratyush Yadav <pratyush@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-05-13MAINTAINERS: add tree for KDUMP and KEXECMike Rapoport (Microsoft)
Patch series "MAINTAINERS: update KEXEC, KDUMP and LIVE UPDATE". KHO and LiveUpdate team is going to pick kdump and kexec patches to their tree at https://git.kernel.org/pub/scm/linux/kernel/git/liveupdate/linux.git Update MAINTAINERS to reflect this change and add kexec@ list to LIVE UPDATE entry. This patch (of 2): KHO and LiveUpdate team is going to pick kdump and kexec patches to their tree at https://git.kernel.org/pub/scm/linux/kernel/git/liveupdate/linux.git Update MAINTAINERS to reflect it. Link: https://lore.kernel.org/20260428124833.1903302-1-rppt@kernel.org Link: https://lore.kernel.org/20260428124833.1903302-2-rppt@kernel.org Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Acked-by: Pasha Tatashin <pasha.tatashin@soleen.com> Acked-by: Baoquan He <baoquan.he@linux.dev> Acked-by: Pratyush Yadav <pratyush@kernel.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Dave Young <ruirui.yang@linux.dev> Cc: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-05-13selftests/mm: run_vmtests.sh: fix destructive tests invocationLuiz Capitulino
Destructive tests should be invoked with -d command-line option, but this won't work today since 'd' is missing in getopts command-line. This commit fixes it. Link: https://lore.kernel.org/214fd9e4-5398-4c26-859e-c982c2e277c3@redhat.com Fixes: f16ff3b692ad ("selftests/mm: run_vmtests.sh: add missing tests") Signed-off-by: Luiz Capitulino <luizcap@redhat.com> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: SeongJae Park <sj@kernel.org> Cc: David Hildenbrand <david@kernel.org> Cc: Liam R. Howlett <liam@infradead.org> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-05-13scripts/gdb: slab: update field names of struct kmem_cacheIllia Ostapyshyn
The commit 5ba6bc27b1f9 ("slab: decouple pointer to barn from kmem_cache_node") reorganized the struct kmem_cache to factor out the per-node fields to the new struct kmem_cache_per_node_ptrs. This causes the gdb scripts for lx-slabinfo and lx-slabtrace fail as they still reference the old structure. Adjust the gdb scripts to match the current state of struct kmem_cache. Link: https://lore.kernel.org/20260427142448.666117-3-illia@yshyn.com Fixes: 5ba6bc27b1f9 ("slab: decouple pointer to barn from kmem_cache_node") Signed-off-by: Illia Ostapyshyn <illia@yshyn.com> Acked-by: Harry Yoo (Oracle) <harry@kernel.org> Acked-by: Vlastimil Babka (SUSE) <vbabka@kernel.org> Cc: Florian Fainelli <florian.fainelli@broadcom.com> Cc: Hao Li <hao.li@linux.dev> Cc: Jan Kiszka <jan.kiszka@siemens.com> Cc: Kieran Bingham <kbingham@kernel.org> Cc: Seongjun Hong <hsj0512@snu.ac.kr> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-05-13scripts/gdb: mm: cast untyped symbols in x86_page_opsIllia Ostapyshyn
The symbols phys_base, _text, and _end, used in x86_page_ops are either defined in assembly or implicitly by the linker. Thus, they lack type information and cause a conversion error after gdb.parse_and_eval. Explicitly cast these expressions to unsigned long. Link: https://lore.kernel.org/20260427142448.666117-2-illia@yshyn.com Fixes: 55f8b4518d14 ("scripts/gdb: implement x86_page_ops in mm.py") Signed-off-by: Illia Ostapyshyn <illia@yshyn.com> Cc: Florian Fainelli <florian.fainelli@broadcom.com> Cc: Jan Kiszka <jan.kiszka@siemens.com> Cc: Kieran Bingham <kbingham@kernel.org> Cc: Vlastimil Babka <vbabka@suse.com> Cc: Hao Li <hao.li@linux.dev> Cc: Harry Yoo <harry@kernel.org> Cc: Seongjun Hong <hsj0512@snu.ac.kr> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-05-13mm/damon: fix damos_stat tracepoint format for sz_appliedSeongJae Park
The print format is wrongly marking sz_applied as sz_tried. Fix it. Link: https://lore.kernel.org/20260426193119.88095-1-sj@kernel.org Fixes: 804c26b961da ("mm/damon/core: add trace point for damos stat per apply interval") Signed-off-by: SeongJae Park <sj@kernel.org> Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: <stable@vger.kernel.org> # 7.0.x Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-05-13mm/damon/sysfs-schemes: call missing mem_cgroup_iter_break()SeongJae Park
damon_sysfs_memcg_path_to_id() breaks mem_cgroup_iter() loop without calling mem_cgroup_iter_break(). This leaks the cgroup reference. Fix the issue by calling mem_cgroup_iter_break() before the break. The issue was discovered [1] by Sashiko. Link: https://lore.kernel.org/20260426173625.86521-1-sj@kernel.org Link: https://lore.kernel.org/20260423004148.74722-1-sj@kernel.org [1] Fixes: 29cbb9a13f05 ("mm/damon/sysfs-schemes: implement scheme filters") Signed-off-by: SeongJae Park <sj@kernel.org> Cc: <stable@vger.kernel.org> # 6.3.x Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-05-13mm/migrate_device: fix spinlock leak in migrate_vma_insert_huge_pmd_pageSunny Patel
When check_stable_address_space() fails after the PMD spinlock has been acquired via pmd_lock(), the code jumps directly to the abort label, bypassing the spin_unlock() call in unlock_abort. This causes the PMD spinlock to be permanently held, leading to a deadlock. Change the goto target from abort to unlock_abort to ensure the spinlock is always released on this error path. Link: https://lore.kernel.org/20260425133537.17463-1-nueralspacetech@gmail.com Fixes: a30b48bf1b24 ("mm/migrate_device: implement THP migration of zone device pages") Signed-off-by: Sunny Patel <nueralspacetech@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Zi Yan <ziy@nvidia.com> Acked-by: Balbir Singh <balbirs@nvidia.com> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Cc: Alistair Popple <apopple@nvidia.com> Cc: Byungchul Park <byungchul@sk.com> Cc: Gregory Price <gourry@gourry.net> Cc: "Huang, Ying" <ying.huang@linux.alibaba.com> Cc: Joshua Hahn <joshua.hahnjy@gmail.com> Cc: Matthew Brost <matthew.brost@intel.com> Cc: Rakie Kim <rakie.kim@sk.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-05-13FDDI: defza: Sanitise the reset safety timerMaciej W. Rozycki
The reset actions of the DEFZA adapters are exceedingly slow, taking up to 30 seconds to complete by the device spec and typically in the range of 10 seconds in reality, as required for the device RTOS to boot, still quite a lot. Therefore a state machine is used that's interrupt driven, however a safety mechanism is required in case of adapter malfunction, so that if no state change interrupt has arrived in time, then the situation is taken care of. The safety mechanism depends on the origin of the reset. For regular adapter initialisation at the device probe time a sleep is requested. However a reset is also required by the device spec when the adapter has transitioned into the halted state, such as in response to a PC Trace event in the course of ring fault recovery, possibly a common network event. In that case no sleep is possible as a device halt is reported at the hardirq level. A timer is therefore set up to ensure progress in case no adapter state change interrupt has arrived in time, but as from commit 168f6b6ffbee ("timers: Use del_timer_sync() even on UP") a warning is issued as the timer is deleted in the hardirq handler upon an expected state change: defza: v.1.1.4 Oct 6 2018 Maciej W. Rozycki tc2: DEC FDDIcontroller 700 or 700-C at 0x18000000, irq 4 tc2: resetting the board... ------------[ cut here ]------------ WARNING: kernel/time/timer.c:1611 at __timer_delete_sync+0x104/0x120, CPU#0: swapper/0/0 Modules linked in: CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 7.0.0-dirty #2 VOLUNTARY Stack : 9800000002027d08 00000000140120e0 0000000000000000 ffffffff8089d468 0000000000000000 0000000000000000 ffffffff807ed6b8 ffffffff80897458 ffffffff80897400 9800000002027b88 0000000000000000 7070617773203a6d 0000000000000000 9800000002027ba4 0000000000001000 6465746e69617420 0000000000000000 ffffffff807ed6b8 00000000140120e0 0000000000000009 000000000000064b ffffffff800dd14c 0000000000000036 9800000002184000 0000000000000000 0000000000000020 0000000000000000 ffffffff80910000 ffffffff8085c000 9800000002027c70 0000000000000001 ffffffff80045fa0 0000000000000000 0000000000000000 0000000000000000 0000000000000009 000000000000064b ffffffff800502b8 ffffffff807ed6b8 ffffffff80045fa0 ... Call Trace: [<ffffffff800502b8>] show_stack+0x28/0xf0 [<ffffffff80045fa0>] dump_stack_lvl+0x48/0x7c [<ffffffff80068c98>] __warn+0xa0/0x128 [<ffffffff8004120c>] warn_slowpath_fmt+0x64/0xa4 [<ffffffff800dd14c>] __timer_delete_sync+0x104/0x120 [<ffffffff804934ac>] fza_interrupt+0xc74/0xeb8 [<ffffffff800c6390>] __handle_irq_event_percpu+0x70/0x228 [<ffffffff800c6560>] handle_irq_event_percpu+0x18/0x78 [<ffffffff800cc320>] handle_percpu_irq+0x50/0x80 [<ffffffff800c5970>] generic_handle_irq+0x90/0xd0 [<ffffffff806e956c>] do_IRQ+0x1c/0x30 [<ffffffff8004ad4c>] handle_int+0x148/0x154 [<ffffffff800ab7c0>] do_idle+0x40/0x108 [<ffffffff800abb0c>] cpu_startup_entry+0x2c/0x38 [<ffffffff806dfec8>] kernel_init+0x0/0x108 ---[ end trace 0000000000000000 ]--- tc2: OK tc2: model 700 (DEFZA-AA), MMF PMD, address 08-00-2b-xx-xx-xx tc2: ROM rev. 1.0, firmware rev. 1.2, RMC rev. A, SMT ver. 1 tc2: link unavailable ------------[ cut here ]------------ WARNING: kernel/time/timer.c:1611 at __timer_delete_sync+0x104/0x120, CPU#0: swapper/0/0 Modules linked in: CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G W 7.0.0-dirty #2 VOLUNTARY Tainted: [W]=WARN Stack : 9800000002027d08 00000000140120e0 0000000000000000 ffffffff8089d468 0000000000000000 0000000000000000 ffffffff807ed6b8 ffffffff80897458 ffffffff80897400 9800000002027b88 0000000000000000 0000000000000000 0000000000000000 9800000002027ba4 0000000000001000 0000000000000000 0000000000000000 ffffffff807ed6b8 00000000140120e0 0000000000000009 000000000000064b ffffffff800dd14c 0000000000000036 9800000002184000 0000000000000000 0000000000000020 0000000000000000 ffffffff80910000 ffffffff8085c000 9800000002027c70 0000000000000001 ffffffff80045fa0 0000000000000000 0000000000000000 0000000000000000 0000000000000009 000000000000064b ffffffff800502b8 ffffffff807ed6b8 ffffffff80045fa0 ... Call Trace: [<ffffffff800502b8>] show_stack+0x28/0xf0 [<ffffffff80045fa0>] dump_stack_lvl+0x48/0x7c [<ffffffff80068c98>] __warn+0xa0/0x128 [<ffffffff8004120c>] warn_slowpath_fmt+0x64/0xa4 [<ffffffff800dd14c>] __timer_delete_sync+0x104/0x120 [<ffffffff804934ac>] fza_interrupt+0xc74/0xeb8 [<ffffffff800c6390>] __handle_irq_event_percpu+0x70/0x228 [<ffffffff800c6560>] handle_irq_event_percpu+0x18/0x78 [<ffffffff800cc320>] handle_percpu_irq+0x50/0x80 [<ffffffff800c5970>] generic_handle_irq+0x90/0xd0 [<ffffffff806e956c>] do_IRQ+0x1c/0x30 [<ffffffff8004ad4c>] handle_int+0x148/0x154 [<ffffffff806de8a4>] arch_local_irq_disable+0x4/0x28 [<ffffffff800ab7d0>] do_idle+0x50/0x108 [<ffffffff800abb0c>] cpu_startup_entry+0x2c/0x38 [<ffffffff806dfec8>] kernel_init+0x0/0x108 ---[ end trace 0000000000000000 ]--- tc2: registered as fddi0 The immediate origin of the new warning is the switch away from aliasing del_timer_sync() to del_timer() (timer_delete_sync() to timer_delete() in terms of current function names) for UP configurations, which however is the only choice for this driver anyway as no SMP hardware supports the TURBOchannel bus this device interfaces to. Therefore there is a very remote issue only this is a sign of. Specifically if an adapter reset issued upon a transition to the halted state times out and first triggers fza_reset_timer() for another reset assertion, which then schedules fza_reset_timer() for reset deassertion and then that second call is pre-empted after poking at the hardware, but before the timer has been rearmed and owing to high system load causing exceedingly high scheduling latency control is not handed back before a transition to the uninitialised state has caused the timer to be deleted even before it has been started, then fza_reset_timer() will be called yet again and issue another reset even though by then the adapter has already recovered. Prevent this situation from happening by switching to timer_delete() for the transition to the halted state and protect the code region affected with a spinlock, also to make sure add_timer() has not been called twice in a row due to an execution race between the interrupt handler and the timer handler (though it could only happen on SMP, but let's keep the driver clean). It's a very unlikely sequence of events to happen and therefore there's no point in trying to be overly clever about it, such as by placing printk() calls outside the protection. For the transition to the uninitialised state switch to timer_delete_sync_try() instead, so that a timer isn't deleted that's just been rearmed by the timer handler and needs to watch for the device to come out of reset again (again, an SMP scenario only). Retain timer_delete_sync() invocations outside the hardirq context for a stray timer not to fire once device structures have been released. Fixes: 61414f5ec9834 ("FDDI: defza: Add support for DEC FDDIcontroller 700 TURBOchannel adapter") Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-05-13dt-bindings: watchdog: renesas,rzn1-wdt: interrupts are not requiredWolfram Sang
It is now understood how the watchdog can do its job without the need of an interrupt. So, it is not required anymore but optional. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Reviewed-by: Herve Codina <herve.codina@bootlin.com> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Acked-by: Rob Herring (Arm) <robh@kernel.org> Link: https://lore.kernel.org/r/20260507102410.43384-5-wsa+renesas@sang-engineering.com Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2026-05-13drm/hyperv: During panic do VMBus unload after frame buffer is flushedMichael Kelley
In a VM, Linux panic information (reason for the panic, stack trace, etc.) may be written to a serial console and/or a virtual frame buffer for a graphics console. The latter may need to be flushed back to the host hypervisor for display. The current Hyper-V DRM driver for the frame buffer does the flushing *after* the VMBus connection has been unloaded, such that panic messages are not displayed on the graphics console. A user with a Hyper-V graphics console is left with just a hung empty screen after a panic. The enhanced control that DRM provides over the panic display in the graphics console is similarly non-functional. Commit 3671f3777758 ("drm/hyperv: Add support for drm_panic") added the Hyper-V DRM driver support to flush the virtual frame buffer. It provided necessary functionality but did not handle the sequencing problem with VMBus unload. Fix the full problem by using VMBus functions to suppress the VMBus unload that is normally done by the VMBus driver in the panic path. Then after the frame buffer has been flushed, do the VMBus unload so that a kdump kernel can start cleanly. As expected, CONFIG_DRM_PANIC must be selected for these changes to have effect. As a side benefit, the enhanced features of the DRM panic path are also functional. Fixes: 3671f3777758 ("drm/hyperv: Add support for drm_panic") Signed-off-by: Michael Kelley <mhklinux@outlook.com> Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com> Signed-off-by: Wei Liu <wei.liu@kernel.org>