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adsp_alloc_memory_region()
The devm_ioremap_resource_wc() function never returns NULL, it returns
error pointers. Update the check to match.
Fixes: c70b9d5fdcd7 ("remoteproc: qcom: Use of_reserved_mem_region_* functions for "memory-region"")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://lore.kernel.org/r/6d6b1b0fb6a61b5155a640507217fd7e658858cf.1764427595.git.dan.carpenter@linaro.org
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
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Avoid scanning SAS/SATA devices in channel 1 when SAS transport is
enabled, as the SAS/SATA devices are exposed through channel 0.
Signed-off-by: Suganath Prabu S <suganath-prabu.subramani@broadcom.com>
Signed-off-by: Ranjan Kumar <ranjan.kumar@broadcom.com>
Link: https://lore.kernel.org/stable/20251120071955.463475-1-suganath-prabu.subramani%40broadcom.com
Link: https://patch.msgid.link/20251120071955.463475-1-suganath-prabu.subramani@broadcom.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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If allocation of cmd->t_task_cdb fails, it remains NULL but is later
dereferenced in the 'err' path.
In case of error, reset NULL t_task_cdb value to point at the default
fixed-size buffer.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Fixes: 9e95fb805dc0 ("scsi: target: Fix NULL pointer dereference")
Cc: stable@vger.kernel.org
Signed-off-by: Andrey Vatoropin <a.vatoropin@crpt.ru>
Reviewed-by: Mike Christie <michael.christie@oracle.com>
Link: https://patch.msgid.link/20251118084014.324940-1-a.vatoropin@crpt.ru
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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When a W-LUN resume fails, its parent devices in the SCSI hierarchy,
including the scsi_target, may be runtime suspended. Subsequently, the
error handler in ufshcd_recover_pm_error() fails to set the W-LUN device
back to active because the parent target is not active. This results in
the following errors:
google-ufshcd 3c2d0000.ufs: ufshcd_err_handler started; HBA state eh_fatal; ...
ufs_device_wlun 0:0:0:49488: START_STOP failed for power mode: 1, result 40000
ufs_device_wlun 0:0:0:49488: ufshcd_wl_runtime_resume failed: -5
...
ufs_device_wlun 0:0:0:49488: runtime PM trying to activate child device 0:0:0:49488 but parent (target0:0:0) is not active
Address this by:
1. Ensuring the W-LUN's parent scsi_target is runtime resumed before
attempting to set the W-LUN to active within
ufshcd_recover_pm_error().
2. Explicitly checking for power.runtime_error on the HBA and W-LUN
devices before calling pm_runtime_set_active() to clear the error
state.
3. Adding pm_runtime_get_sync(hba->dev) in
ufshcd_err_handling_prepare() to ensure the HBA itself is active
during error recovery, even if a child device resume failed.
These changes ensure the device power states are managed correctly
during error recovery.
Signed-off-by: Brian Kao <powenkao@google.com>
Tested-by: Brian Kao <powenkao@google.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://patch.msgid.link/20251112063214.1195761-1-powenkao@google.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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If we get a signal, we need to restore the vm_refcnt. We don't think that
the refcount can actually be decremented to zero here as it requires the
VMA to be detached, and the vma_mark_detached() uses TASK_UNINTERRUPTIBLE.
However, that's a bit subtle, so handle it as if the refcount was zero at
the start of this function.
Link: https://lkml.kernel.org/r/20251128040100.3022561-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reported-by: syzbot+5b19bad23ac7f44bf8b8@syzkaller.appspotmail.com
Fixes: 2197bb60f890 ("mm: add vma_start_write_killable()")
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The loop breaks immediately after finding the first swap device and
never modifies the list. Replace plist_for_each_entry_safe() with
plist_for_each_entry() and remove the unused next variable.
Link: https://lkml.kernel.org/r/20251127100303.783198-3-youngjun.park@lge.com
Signed-off-by: Youngjun Park <youngjun.park@lge.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Acked-by: Kairui Song <kasong@tencent.com>
Acked-by: Chris Li <chrisl@kernel.org>
Cc: Barry Song <baohua@kernel.org>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "mm/swapfile: fix and cleanup swap list iterations", v2.
This series fixes a potential list iteration issue in swap_sync_discard()
when devices are removed, and includes a cleanup for
__folio_throttle_swaprate().
This patch (of 2):
When the next node is removed from the plist (e.g. by swapoff),
plist_del() makes the node point to itself, causing the iteration to loop
on the same entry indefinitely.
Add a plist_node_empty() check to detect this case and restart iteration,
allowing swap_sync_discard() to continue processing remaining swap devices
that still have pending discard entries.
Additionally, switch from swap_avail_lock/swap_avail_head to
swap_lock/swap_active_head so that iteration is only affected by swapoff
operations rather than frequent availability changes, reducing exceptional
condition checks and lock contention.
Link: https://lkml.kernel.org/r/20251127100303.783198-1-youngjun.park@lge.com
Link: https://lkml.kernel.org/r/20251127100303.783198-2-youngjun.park@lge.com
Fixes: 686ea517f471 ("mm, swap: do not perform synchronous discard during allocation")
Signed-off-by: Youngjun Park <youngjun.park@lge.com>
Suggested-by: Kairui Song <kasong@tencent.com>
Acked-by: Kairui Song <kasong@tencent.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Chris Li <chrisl@kernel.org>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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make_uffd_wp_huge_pte() should return after handling a huge_pte_none()
pte.
Link: https://lkml.kernel.org/r/66178124-ebdf-4e23-b8ca-ed3eb8030c81@lucifer.local
Fixes: 03bfbc3ad6e4 ("mm: remove is_hugetlb_entry_[migration, hwpoisoned]()")
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reported-by: Vlastimil Babka <vbabka@suse.cz>
Closes: https://lkml.kernel.org/r/dc483db3-be4d-45f7-8b40-a28f5d8f5738@suse.cz
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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During system shutdown, KFENCE can cause IPI synchronization issues if it
remains active through the reboot process. To prevent this, register a
reboot notifier that disables KFENCE and cancels any pending timer work
early in the shutdown sequence.
This is only necessary when CONFIG_KFENCE_STATIC_KEYS is enabled, as this
configuration sends IPIs that can interfere with shutdown. Without static
keys, no IPIs are generated and KFENCE can safely remain active.
The notifier uses maximum priority (INT_MAX) to ensure KFENCE shuts down
before other subsystems that might still depend on stable memory
allocation behavior.
This fixes a late kexec CSD lockup[1] when kfence is trying to IPI a CPU
that is busy in a IRQ-disabled context printing characters to the console.
Link: https://lkml.kernel.org/r/20251127-kfence-v2-1-daeccb5ef9aa@debian.org
Link: https://lkml.kernel.org/r/20251126-kfence-v1-1-5a6e1d7c681c@debian.org
Link: https://lore.kernel.org/all/sqwajvt7utnt463tzxgwu2yctyn5m6bjwrslsnupfexeml6hkd@v6sqmpbu3vvu/ [1]
Fixes: 0ce20dd84089 ("mm: add Kernel Electric-Fence infrastructure")
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The dec_lruvec_kmem_state helper is unused by any caller and can be safely
removed. Meanwhile, the inc_lruvec_kmem_state helper is only referenced
by shadow_lru_isolate, retaining these two helpers is unnecessary. This
patch removes both helper functions to eliminate redundant code.
Link: https://lkml.kernel.org/r/20251126020435.1511637-1-chenridong@huaweicloud.com
Signed-off-by: Chen Ridong <chenridong@huawei.com>
Acked-by: Qi Zheng <zhengqi.arch@bytedance.com>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Lu Jialin <lujialin4@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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In "uffd-stress.c" & "uffd-unit-tests.c". address of char variable having
garbage value (uninitialized) is passed to 'write' syscall triggers
warning.
uffd-stress.c:246:39: warning: variable 'c' is uninitialized when
passed as a const pointer argument here
[-Wuninitialized-const-pointer]
uffd-unit-tests.c:581:31: warning: variable 'c' is uninitialized
when passed as a const pointer argument here
[-Wuninitialized-const-pointer]
so the fix is to assign char variable to '\0' to prevent writing of
garbage value.
Link: https://lkml.kernel.org/r/20251126160830.52124-1-ankitkhushwaha.linux@gmail.com
Signed-off-by: Ankit Khushwaha <ankitkhushwaha.linux@gmail.com>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Bill Wendling <morbo@google.com>
Cc: Justin Stitt <justinstitt@google.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Most of the DEBUG_RODATA_TEST section is indented by four spaces instead
of the customary single TAB.
Link: https://lkml.kernel.org/r/74f39b1bffc6ed802088cb3e7d17b4c82330e8b3.1764058676.git.geert@linux-m68k.org
Fixes: 2959a5f726f6 ("mm: add arch-independent testcases for RODATA")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Jinbum Park <jinb.park7@gmail.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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It is useful to transition to using a bitmap for VMA flags so we can avoid
running out of flags, especially for 32-bit kernels which are constrained
to 32 flags, necessitating some features to be limited to 64-bit kernels
only.
By doing so, we remove any constraint on the number of VMA flags moving
forwards no matter the platform and can decide in future to extend beyond
64 if required.
We start by declaring an opaque types, vma_flags_t (which resembles
mm_struct flags of type mm_flags_t), setting it to precisely the same size
as vm_flags_t, and place it in union with vm_flags in the VMA declaration.
We additionally update struct vm_area_desc equivalently placing the new
opaque type in union with vm_flags.
This change therefore does not impact the size of struct vm_area_struct or
struct vm_area_desc.
In order for the change to be iterative and to avoid impacting
performance, we designate VM_xxx declared bitmap flag values as those
which must exist in the first system word of the VMA flags bitmap.
We therefore declare vma_flags_clear_all(), vma_flags_overwrite_word(),
vma_flags_overwrite_word(), vma_flags_overwrite_word_once(),
vma_flags_set_word() and vma_flags_clear_word() in order to allow us to
update the existing vm_flags_*() functions to utilise these helpers.
This is a stepping stone towards converting users to the VMA flags bitmap
and behaves precisely as before.
By doing this, we can eliminate the existing private vma->__vm_flags field
in the vma->vm_flags union and replace it with the newly introduced opaque
type vma_flags, which we call flags so we refer to the new bitmap field as
vma->flags.
We update vma_flag_[test, set]_atomic() to account for the change also.
We adapt vm_flags_reset_once() to only clear those bits above the first
system word providing write-once semantics to the first system word (which
it is presumed the caller requires - and in all current use cases this is
so).
As we currently only specify that the VMA flags bitmap size is equal to
BITS_PER_LONG number of bits, this is a noop, but is defensive in
preparation for a future change that increases this.
We additionally update the VMA userland test declarations to implement the
same changes there.
Finally, we update the rust code to reference vma->vm_flags on update
rather than vma->__vm_flags which has been removed. This is safe for now,
albeit it is implicitly performing a const cast.
Once we introduce flag helpers we can improve this more.
No functional change intended.
Link: https://lkml.kernel.org/r/bab179d7b153ac12f221b7d65caac2759282cfe9.1764064557.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Acked-by: Alice Ryhl <aliceryhl@google.com> [rust]
Cc: Alex Gaynor <alex.gaynor@gmail.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andreas Hindborg <a.hindborg@kernel.org>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Ben Segall <bsegall@google.com>
Cc: Björn Roy Baron <bjorn3_gh@protonmail.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Chris Li <chrisl@kernel.org>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Gary Guo <gary@garyguo.net>
Cc: Gregory Price <gourry@gourry.net>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Mathew Brost <matthew.brost@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Trevor Gross <tmgross@umich.edu>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Wei Xu <weixugc@google.com>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The userland VMA test code relied on an internal implementation detail -
the existence of vma->__vm_flags to directly access VMA flags. There is
no need to do so when we have the vm_flags_*() helper functions available.
This is ugly, but also a subsequent commit will eliminate this field
altogether so this will shortly become broken.
This patch has us utilise the helper functions instead.
Link: https://lkml.kernel.org/r/6275c53a6bb20743edcbe92d3e130183b47d18d0.1764064557.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Pedro Falcato <pfalcato@suse.de>
Acked-by: Alice Ryhl <aliceryhl@google.com> [rust]
Cc: Alex Gaynor <alex.gaynor@gmail.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andreas Hindborg <a.hindborg@kernel.org>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Ben Segall <bsegall@google.com>
Cc: Björn Roy Baron <bjorn3_gh@protonmail.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Chris Li <chrisl@kernel.org>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Gary Guo <gary@garyguo.net>
Cc: Gregory Price <gourry@gourry.net>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Mathew Brost <matthew.brost@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Trevor Gross <tmgross@umich.edu>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Wei Xu <weixugc@google.com>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The __mm_flags_set_word() function is slightly ambiguous - we use 'set' to
refer to setting individual bits (such as in mm_flags_set()) but here we
use it to refer to overwriting the value altogether.
Rename it to __mm_flags_overwrite_word() to eliminate this ambiguity.
We additionally simplify the functions, eliminating unnecessary
bitmap_xxx() operations (the compiler would have optimised these out but
it's worth being as clear as we can be here).
Link: https://lkml.kernel.org/r/8f0bc556e1b90eca8ea5eba41f8d5d3f9cd7c98a.1764064557.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Acked-by: Alice Ryhl <aliceryhl@google.com> [rust]
Cc: Alex Gaynor <alex.gaynor@gmail.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andreas Hindborg <a.hindborg@kernel.org>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Ben Segall <bsegall@google.com>
Cc: Björn Roy Baron <bjorn3_gh@protonmail.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Chris Li <chrisl@kernel.org>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Gary Guo <gary@garyguo.net>
Cc: Gregory Price <gourry@gourry.net>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Mathew Brost <matthew.brost@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Trevor Gross <tmgross@umich.edu>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Wei Xu <weixugc@google.com>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "initial work on making VMA flags a bitmap", v3.
We are in the rather silly situation that we are running out of VMA flags
as they are currently limited to a system word in size.
This leads to absurd situations where we limit features to 64-bit
architectures only because we simply do not have the ability to add a flag
for 32-bit ones.
This is very constraining and leads to hacks or, in the worst case, simply
an inability to implement features we want for entirely arbitrary reasons.
This also of course gives us something of a Y2K type situation in mm where
we might eventually exhaust all of the VMA flags even on 64-bit systems.
This series lays the groundwork for getting away from this limitation by
establishing VMA flags as a bitmap whose size we can increase in future
beyond 64 bits if required.
This is necessarily a highly iterative process given the extensive use of
VMA flags throughout the kernel, so we start by performing basic steps.
Firstly, we declare VMA flags by bit number rather than by value,
retaining the VM_xxx fields but in terms of these newly introduced
VMA_xxx_BIT fields.
While we are here, we use sparse annotations to ensure that, when dealing
with VMA bit number parameters, we cannot be passed values which are not
declared as such - providing some useful type safety.
We then introduce an opaque VMA flag type, much like the opaque mm_struct
flag type introduced in commit bb6525f2f8c4 ("mm: add bitmap mm->flags
field"), which we establish in union with vma->vm_flags (but still set at
system word size meaning there is no functional or data type size change).
We update the vm_flags_xxx() helpers to use this new bitmap, introducing
sensible helpers to do so.
This series lays the foundation for further work to expand the use of
bitmap VMA flags and eventually eliminate these arbitrary restrictions.
This patch (of 4):
In order to lay the groundwork for VMA flags being a bitmap rather than a
system word in size, we need to be able to consistently refer to VMA flags
by bit number rather than value.
Take this opportunity to do so in an enum which we which is additionally
useful for tooling to extract metadata from.
This additionally makes it very clear which bits are being used for what
at a glance.
We use the VMA_ prefix for the bit values as it is logical to do so since
these reference VMAs. We consistently suffix with _BIT to make it clear
what the values refer to.
We declare bit values even when the flags that use them would not be
enabled by config options as this is simply clearer and clearly defines
what bit numbers are used for what, at no additional cost.
We declare a sparse-bitwise type vma_flag_t which ensures that users can't
pass around invalid VMA flags by accident and prepares for future work
towards VMA flags being a bitmap where we want to ensure bit values are
type safe.
To make life easier, we declare some macro helpers - DECLARE_VMA_BIT()
allows us to avoid duplication in the enum bit number declarations (and
maintaining the sparse __bitwise attribute), and INIT_VM_FLAG() is used to
assist with declaration of flags.
Unfortunately we can't declare both in the enum, as we run into issue with
logic in the kernel requiring that flags are preprocessor definitions, and
additionally we cannot have a macro which declares another macro so we
must define each flag macro directly.
Additionally, update the VMA userland testing vma_internal.h header to
include these changes.
We also have to fix the parameters to the vma_flag_*_atomic() functions
since VMA_MAYBE_GUARD_BIT is now of type vma_flag_t and sparse will
complain otherwise.
We have to update some rather silly if-deffery found in mm/task_mmu.c
which would otherwise break.
Finally, we update the rust binding helper as now it cannot auto-detect
the flags at all.
Link: https://lkml.kernel.org/r/cover.1764064556.git.lorenzo.stoakes@oracle.com
Link: https://lkml.kernel.org/r/3a35e5a0bcfa00e84af24cbafc0653e74deda64a.1764064556.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Acked-by: Alice Ryhl <aliceryhl@google.com> [rust]
Cc: Alex Gaynor <alex.gaynor@gmail.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andreas Hindborg <a.hindborg@kernel.org>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Ben Segall <bsegall@google.com>
Cc: Björn Roy Baron <bjorn3_gh@protonmail.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Chris Li <chrisl@kernel.org>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Gary Guo <gary@garyguo.net>
Cc: Gregory Price <gourry@gourry.net>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Mathew Brost <matthew.brost@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Trevor Gross <tmgross@umich.edu>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Wei Xu <weixugc@google.com>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The spelling of the word "relases" is incorrect; it should be "releases".
Link: https://lkml.kernel.org/r/20251125020522.1913-1-chuguangqing@inspur.com
Signed-off-by: Chu Guangqing <chuguangqing@inspur.com>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
monotonicity
calculate_totalreserve_pages() currently finds the maximum
lowmem_reserve[j] for a zone by scanning the full forward range [j =
zone_idx .. MAX_NR_ZONES). However, for a given zone i, the
lowmem_reserve[j] array (for j > i) is naturally expected to form a
monotonically non-decreasing sequence in j, not as an implementation
detail, but as a consequence that naturally arises from the semantics of
lowmem_reserve[].
For zone "i", lowmem_reserve[j] expresses how many pages in zone i must
effectively be kept in reserve when deciding whether an allocation class
that may allocate from zones up to j is allowed to fall back into i. It
protects less flexible allocation classes (which cannot use higher zones)
from being starved by more flexible ones.
Viewed from this semantics, it is natural to expect a partial ordering in
j: as j increases, the allocation class gains access to a strictly larger
set of fallback zones. Therefore lowmem_reserve[j] is expected to be
monotonically non-decreasing in j: more flexible allocation classes must
not be allowed to deplete low zones more aggressively than less flexible
ones.
In other words, if lowmem_reserve[j] were ever observed to *decrease* as j
grows, that would be unexpected from the reserve semantics' point of view
and would likely indicate a semantic change or a misconfiguration.
The current implementation in setup_per_zone_lowmem_reserve() reflects
this policy by accumulating managed pages from higher zones and applying
the configured ratio, which results in a non-decreasing sequence. This
patch makes calculate_totalreserve_pages() rely on that monotonicity
explicitly and finds the maximum reserve value by scanning backward and
stopping at the first non-zero entry. This avoids unnecessary iteration
and reflects the conceptual model more directly. No functional behavior
changes.
To maintain this assumption explicitly, a comment is added next to
setup_per_zone_lowmem_reserve() documenting the monotonicity expectation
and noting that calculate_totalreserve_pages() relies on it.
Link: https://lkml.kernel.org/r/tencent_EB0FED91B01B1F8B6DAEE96719C5F5797F07@qq.com
Signed-off-by: fujunjie <fujunjie1@qq.com>
Acked-by: Zi Yan <ziy@nvidia.com>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
We have a colocation cluster used for deploying both offline and online
services simultaneously. In this environment, we encountered a
scenario where direct memory reclamation was triggered due to kswapd
not running.
1. When applications start up, rapidly consume memory, or experience
network traffic bursts, the kernel reaches steal_suitable_fallback(),
which sets watermark_boost and subsequently wakes kswapd.
2. In the core logic of kswapd thread (balance_pgdat()), when reclaim is
triggered by watermark_boost, the maximum priority is 10. Higher
priority values mean less aggressive LRU scanning, which can result in
no pages being reclaimed during a single scan cycle:
if (nr_boost_reclaim && sc.priority == DEF_PRIORITY - 2)
raise_priority = false;
3. Additionally, many of our pods are configured with memory.low, which
prevents memory reclamation in certain cgroups, further increasing the
chance of failing to reclaim memory.
4. This eventually causes pgdat->kswapd_failures to continuously
accumulate, exceeding MAX_RECLAIM_RETRIES, and consequently kswapd
stops working. At this point, the system's available memory is still
significantly above the high watermark -- it's inappropriate for kswapd
to stop under these conditions.
The final observable issue is that a brief period of rapid memory
allocation causes kswapd to stop running, ultimately triggering direct
reclaim and making the applications unresponsive.
This problem leading to direct memory reclamation has been a
long-standing issue in our production environment. We initially held
the simple assumption that it was caused by applications allocating
memory too rapidly for kswapd to keep up with reclamation. However,
after we began monitoring kswapd's runtime behavior, we discovered a
different pattern:
kswapd initially exhibits very aggressive activity even when there is
still considerable free memory, but it subsequently stops running
entirely, even as memory levels approach the low watermark.
In summary, both boosted watermarks and memory.low increase the
probability of kswapd operation failures.
This patch specifically addresses the scenario involving boosted
watermarks by not incrementing kswapd_failures when reclamation fails.
A more general solution, potentially addressing memory.low or other
cases, requires further discussion.
Link: https://lkml.kernel.org/r/53de0b3ee0b822418e909db29bfa6513faff9d36@linux.dev
Link: https://lkml.kernel.org/r/20251024022711.382238-1-jiayuan.chen@linux.dev
Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Updating a BPF_MAP_TYPE_HASH_OF_MAPS or BPF_MAP_TYPE_ARRAY_OF_MAPS via
bpf_map_update_elem() is very expensive.
In one of our workloads, we're inserting ~1400 maps of type
BPF_MAP_TYPE_ARRAY into a BPF_MAP_TYPE_ARRAY_OF_MAPS. This takes ~21
seconds on a single thread, with an average of ~15ms per call:
Function Name: map_update_elem
Number of calls: 1369
Total time: 21s 182ms 966µs
Maximum: 47ms 937µs
Average: 15ms 473µs
Minimum: 7µs
Profiling shows that nearly all of this time is going to synchronize_rcu(),
via maybe_wait_bpf_programs() in map_update_elem().
The call to synchronize_rcu() is done to ensure that after
bpf_map_update_elem() returns, no BPF programs are still looking at the old
value of the map, per commit 1ae80cf31938 ("bpf: wait for running BPF
programs when updating map-in-map").
As discussed on the bpf mailing list, replace synchronize_rcu() with
synchronize_rcu_expedited(). This is 175x faster: it now takes an average
of 88 microseconds per call, for a total of 127 milliseconds in the same
benchmark:
Function Name: map_update_elem
Number of calls: 1439
Total time: 127ms 626µs
Maximum: 445µs
Average: 88µs
Minimum: 10µs
Link: https://lore.kernel.org/bpf/CAH6OuBR=w2kybK6u7aH_35B=Bo1PCukeMZefR=7V4Z2tJNK--Q@mail.gmail.com/
Signed-off-by: Ritesh Oedayrajsingh Varma <ritesh@superluminal.eu>
Link: https://lore.kernel.org/r/20251128000422.20462-1-ritesh@superluminal.eu
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Make kprobe_multi_link_prog_run() always inline to obtain better
performance. Before this patch, the bench performance is:
./bench trig-kprobe-multi
Setting up benchmark 'trig-kprobe-multi'...
Benchmark 'trig-kprobe-multi' started.
Iter 0 ( 95.485us): hits 62.462M/s ( 62.462M/prod), [...]
Iter 1 (-80.054us): hits 62.486M/s ( 62.486M/prod), [...]
Iter 2 ( 13.572us): hits 62.287M/s ( 62.287M/prod), [...]
Iter 3 ( 76.961us): hits 62.293M/s ( 62.293M/prod), [...]
Iter 4 (-77.698us): hits 62.394M/s ( 62.394M/prod), [...]
Iter 5 (-13.399us): hits 62.319M/s ( 62.319M/prod), [...]
Iter 6 ( 77.573us): hits 62.250M/s ( 62.250M/prod), [...]
Summary: hits 62.338 ± 0.083M/s ( 62.338M/prod)
And after this patch, the performance is:
Iter 0 (454.148us): hits 66.900M/s ( 66.900M/prod), [...]
Iter 1 (-435.540us): hits 68.925M/s ( 68.925M/prod), [...]
Iter 2 ( 8.223us): hits 68.795M/s ( 68.795M/prod), [...]
Iter 3 (-12.347us): hits 68.880M/s ( 68.880M/prod), [...]
Iter 4 ( 2.291us): hits 68.767M/s ( 68.767M/prod), [...]
Iter 5 ( -1.446us): hits 68.756M/s ( 68.756M/prod), [...]
Iter 6 ( 13.882us): hits 68.657M/s ( 68.657M/prod), [...]
Summary: hits 68.792 ± 0.087M/s ( 68.792M/prod)
As we can see, the performance of kprobe-multi increase from 62M/s to
68M/s.
Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Link: https://lore.kernel.org/r/20251126085246.309942-1-dongml2@chinatelecom.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Alexis Lothoré says:
====================
selftests/bpf: convert test_tc_edt.sh into test_progs
Hello,
this is a (late) v2 to my first attempt to convert the test_tc_edt
script to test_progs. This new version is way simpler, thanks to
Martin's suggestion about properly using the existing network_helpers
rather than reinventing the wheel. It also fixes a small bug in the
measured effective rate.
The converted test roughly follows the original script logic, with two
veths in two namespaces, a TCP connection between a client and a server,
and the client pushing a specific amount of data. Time is recorded
before and after the transmission to compute the effective rate.
There are two knobs driving the robustness of the test in CI:
- the amount of pushed data (the higher, the more precise is the
effective rate)
- the tolerated error margin
The original test was configured with a 20s duration and a 1% error
margin. The new test is configured with 1MB of data being pushed and a
2% error margin, to:
- make the duration tolerable in CI
- while keeping enough margin for rate measure fluctuations depending on
the CI machines load
This has been run multiple times locally to ensure that those values are
sane, and once in CI before sending the series, but I suggest to let it
live a few days in CI to see how it really behaves.
Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
Changes in v2:
- drop custom client/server management
- update bpf program now that server pushes data
- fix effective rate computation
- Link to v1: https://lore.kernel.org/r/20251031-tc_edt-v1-0-5d34a5823144@bootlin.com
---
Alexis Lothoré (eBPF Foundation) (4):
selftests/bpf: rename test_tc_edt.bpf.c section to expose program type
selftests/bpf: integrate test_tc_edt into test_progs
selftests/bpf: remove test_tc_edt.sh
selftests/bpf: do not hardcode target rate in test_tc_edt BPF program
tools/testing/selftests/bpf/Makefile | 2 -
.../testing/selftests/bpf/prog_tests/test_tc_edt.c | 145 +++++++++++++++++++++
tools/testing/selftests/bpf/progs/test_tc_edt.c | 11 +-
tools/testing/selftests/bpf/test_tc_edt.sh | 100 --------------
4 files changed, 151 insertions(+), 107 deletions(-)
---
base-commit: 233a075a1b27070af76d64541cf001340ecff917
change-id: 20251030-tc_edt-3ea8e8d3d14e
Best regards,
====================
Link: https://patch.msgid.link/20251128-tc_edt-v2-0-26db48373e73@bootlin.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
test_tc_edt currently defines the target rate in both the userspace and
BPF parts. This value could be defined once in the userspace part if we
make it able to configure the BPF program before starting the test.
Add a target_rate variable in the BPF part, and make the userspace part
set it to the desired rate before attaching the shaping program.
Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
Link: https://lore.kernel.org/r/20251128-tc_edt-v2-4-26db48373e73@bootlin.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Now that test_tc_edt has been integrated in test_progs, remove the
legacy shell script.
Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
Link: https://lore.kernel.org/r/20251128-tc_edt-v2-3-26db48373e73@bootlin.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
test_tc_edt.sh uses a pair of veth and a BPF program attached to the TX
veth to shape the traffic to 5MBps. It then checks that the amount of
received bytes (at interface level), compared to the TX duration, indeed
matches 5Mbps.
Convert this test script to the test_progs framework:
- keep the double veth setup, isolated in two veths
- run a small tcp server, and connect client to server
- push a pre-configured amount of bytes, and measure how much time has
been needed to push those
- ensure that this rate is in a 2% error margin around the target rate
This two percent value, while being tight, is hopefully large enough to
not make the test too flaky in CI, while also turning it into a small
example of BPF-based shaping.
Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
Link: https://lore.kernel.org/r/20251128-tc_edt-v2-2-26db48373e73@bootlin.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
The test_tc_edt BPF program uses a custom section name, which works fine
when manually loading it with tc, but prevents it from being loaded with
libbpf.
Update the program section name to "tc" to be able to manipulate it with
a libbpf-based C test.
Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
Link: https://lore.kernel.org/r/20251128-tc_edt-v2-1-26db48373e73@bootlin.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Kumar Kartikeya Dwivedi says:
====================
Limited queueing in NMI for rqspinlock
Ritesh reported that he was frequently seeing timeouts in cases which
should have been covered by the AA heuristics. This led to the discovery
of multiple gaps in the current code that could lead to timeouts when
AA heuristics could work to prevent them. More details and investigation
is available in the original threads. [0][1]
This set restores the ability for NMI waiters to queue in the slow path,
and reduces the cases where they would attempt to trylock. However, such
queueing must not happen when interrupting waiters which the NMI itself
depends upon for forward progress; in those cases the trylock fallback
remains, but with a single attempt to avoid aimless attempts to acquire
the lock.
It also closes a possible window in the lock fast path and the unlock
path where NMIs landing between cmpxchg and entry creation, or entry
deletion and unlock would miss the detection of an AA scenario and end
up timing out.
This virtually eliminates all the cases where existing heuristics can
prevent timeouts and quickly recover from a deadlock. More details are
available in the commit logs for each patch.
[0]: https://lore.kernel.org/bpf/CAH6OuBTjG+N=+GGwcpOUbeDN563oz4iVcU3rbse68egp9wj9_A@mail.gmail.com
[1]: https://lore.kernel.org/bpf/20251125203253.3287019-1-memxor@gmail.com
====================
Link: https://patch.msgid.link/20251128232802.1031906-1-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Add stats to observe the success and failure rate of lock acquisition
attempts in various contexts.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20251128232802.1031906-7-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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While previous commits sufficiently address the deadlocks, there are
still scenarios where queueing of waiters in NMIs can exacerbate the
possibility of timeouts.
Consider the case below:
CPU 0
<NMI>
res_spin_lock(A) -> becomes non-head waiter
</NMI>
lock owner in CS or pending waiter spinning
CPU 1
res_spin_lock(A) -> head waiter spinning on owner/pending bits
In such a scenario, the non-head waiter in NMI on CPU 0 will not poll
for deadlocks or timeout since it will simply queue behind previous
waiter (head on CPU 1), and also not enter the trylock fallback since
no rqspinlock queue waiter is active on CPU 0. In such a scenario, the
transaction initiated by the head waiter on CPU 1 will timeout,
signalling the NMI and ending the cyclic dependency, but it will cost
250 ms of time.
Instead, the NMI on CPU 0 could simply check for the presence of an AA
deadlock and only proceed with queueing on success. Add such a check
right before any form of queueing is initiated.
The reason the AA deadlock check is not used in conjunction with
in_nmi() is that a similar case could occur due to a reentrant path
in the owner's critical section, and unconditionally checking for AA
before entering the queueing path avoids expensive timeouts. Non-NMI
reentrancy only happens at controlled points in the slow path (with
specific tracepoints which do not impede the forward progress of a
waiter loop), or in the owner CS, while NMIs can land anywhere.
While this check is only needed for non-head waiter queueing, checking
whether we are head or not is racy without xchg_tail, and after that
point, we are already queued, hence for simplicity we must invoke the
check unconditionally.
Note that a more contrived case could still be constructed by using two
locks, and interrupting the progress of the respective owners by
non-head waiters of the other lock, in an ABBA fashion, which would
still not be covered by the current set of checks and conditions. It
would still lead to a timeout though, and not a deadlock. An ABBA check
cannot happen optimistically before the queueing, since it can be racy,
and needs to be happen continuously during the waiting period, which
would then require an unlinking step for queued NMI/reentrant waiters.
This is beyond the scope of this patch.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20251128232802.1031906-6-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
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The original trylock fallback was inherited from qspinlock, and then
reused for the reentrant NMIs while the slow path is active. However,
under contention, it is very unlikely for the trylock to succeed in
taking the lock. In addition, a trylock also has no fairness guarantees,
and thus is prone to starvation issues under extreme scenarios.
The original qspinlock had no choice in terms of returning an error the
caller; if the node count was breached, it had to fall back to trylock
to attempt to take the lock. In case of rqspinlock, we do have the
option of returning to the user. Thus, simply attempt the trylock once,
and instead of spinning, return an error in case the lock cannot be
taken.
This ends up significantly reducing the time spent in the trylock
fallback, since we no longer wait for the timeout duration trying to
aimlessly acquire the lock when there's a high-probability that under
contention, it won't be available to us anyway.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20251128232802.1031906-5-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
In addition to deferring to the trylock fallback in NMIs, only do so
when an rqspinlock waiter is queued on the current CPU. This is detected
by noticing a non-zero node index. This allows NMI waiters to join the
waiter queue if it isn't interrupting an existing rqspinlock waiter, and
increase the chances of fairly obtaining the lock, performing deadlock
detection as the head, and not being starved while attempting the
trylock.
The trylock path in particular is unlikely to succeed under contention,
as it relies on the lock word becoming 0, which indicates no contention.
This means that the most likely result for NMIs attempting a trylock is
a timeout under contention if they don't hit an AA or ABBA case.
The core problem being addressed through the fixed commit was removing
the dependency edge between an NMI queue waiter and the queue waiter it
is interrupting. Whenever a circular dependency forms, and with no way
to break it (as non-head waiters don't poll for deadlocks or timeouts),
we would enter into a deadlock. A trylock either breaks such an edge by
probing for deadlocks, and finally terminating the waiting loop using a
timeout.
By excluding queueing on CPUs where the node index is non-zero for NMIs,
this sort of dependency is broken. The CPU enters the trylock path for
those cases, and falls back to deadlock checks and timeouts. However, in
other case where it doesn't interrupt the CPU in the slow path while its
queued on the lock, it can join the queue as a normal waiter, and avoid
trylock associated starvation and subsequent timeouts.
There are a few remaining cases here that matter: the NMI can still
preempt the owner in its critical section, and if it queues as a
non-head waiter, it can end up impeding the progress of the owner. While
this won't deadlock, since the head waiter will eventually signal the
NMI waiter to either stop (due to a timeout), it can still lead to long
timeouts. These gaps will be addressed in subsequent commits.
Note that while the node count detection approach is less conservative
than simply deferring NMIs to trylock, it is going to return errors
where attempts to lock B in NMI happen while waiters for lock A are in a
lower context on the same CPU. However, this only occurs when the lower
context is queued in the slow path, and the NMI attempt can proceed
without failure in all other cases. To continue to prevent AA deadlocks
(or ABBA in a similar NMI interrupting lower context pattern), we'd need
a more fleshed out algorithm to unlink NMI waiters after they queue and
detect such cases. However, all that complexity isn't appealing yet to
reduce the failure rate in the small window inside the slow path.
It is important to note that reentrancy in the slow path can also happen
through trace_contention_{begin,end}, but in those cases, unlike an NMI,
the forward progress of the head waiter (or the predecessor in general)
is not being blocked.
Fixes: 0d80e7f951be ("rqspinlock: Choose trylock fallback for NMI waiters")
Reported-by: Ritesh Oedayrajsingh Varma <ritesh@superluminal.eu>
Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20251128232802.1031906-4-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Currently, while we enter the check_timeout call immediately due to the
way the ts.spin is initialized, we still invoke the AA and ABBA checks
in the second invocation, and only initialize the timestamp in the first
one. Since each iteration is at least done with a 1ms delay, this can
add delays in detection of AA deadlocks, up to a ms.
Rework check_timeout() to avoid this. First, call check_deadlock_AA()
while initializing the timestamps for the wait period. This also means
that we only do it once per waiting period, instead of every invocation.
Finally, drop check_deadlock() and call check_deadlock_ABBA() directly.
To save on unnecessary ktime_get_mono_fast_ns() in case of AA deadlock,
sample the time only if it returns 0.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20251128232802.1031906-3-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
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Ritesh reported that timeouts occurred frequently for rqspinlock despite
reentrancy on the same lock on the same CPU in [0]. This patch closes
one of the races leading to this behavior, and reduces the frequency of
timeouts.
We currently have a tiny window between the fast-path cmpxchg and the
grabbing of the lock entry where an NMI could land, attempt the same
lock that was just acquired, and end up timing out. This is not ideal.
Instead, move the lock entry acquisition from the fast path to before
the cmpxchg, and remove the grabbing of the lock entry in the slow path,
assuming it was already taken by the fast path. The TAS fallback is
invoked directly without being preceded by the typical fast path,
therefore we must continue to grab the deadlock detection entry in that
case.
Case on lock leading to missed AA:
cmpxchg lock A
<NMI>
... rqspinlock acquisition of A
... timeout
</NMI>
grab_held_lock_entry(A)
There is a similar case when unlocking the lock. If the NMI lands
between the WRITE_ONCE and smp_store_release, it is possible that we end
up in a situation where the NMI fails to diagnose the AA condition,
leading to a timeout.
Case on unlock leading to missed AA:
WRITE_ONCE(rqh->locks[rqh->cnt - 1], NULL)
<NMI>
... rqspinlock acquisition of A
... timeout
</NMI>
smp_store_release(A->locked, 0)
The patch changes the order on unlock to smp_store_release() succeeded
by WRITE_ONCE() of NULL. This avoids the missed AA detection described
above, but may lead to a false positive if the NMI lands between these
two statements, which is acceptable (and preferred over a timeout).
The original intention of the reverse order on unlock was to prevent the
following possible misdiagnosis of an ABBA scenario:
grab entry A
lock A
grab entry B
lock B
unlock B
smp_store_release(B->locked, 0)
grab entry B
lock B
grab entry A
lock A
! <detect ABBA>
WRITE_ONCE(rqh->locks[rqh->cnt - 1], NULL)
If the store release were is after the WRITE_ONCE, the other CPU would
not observe B in the table of the CPU unlocking the lock B. However,
since the threads are obviously participating in an ABBA deadlock, it
is no longer appealing to use the order above since it may lead to a
250 ms timeout due to missed AA detection.
[0]: https://lore.kernel.org/bpf/CAH6OuBTjG+N=+GGwcpOUbeDN563oz4iVcU3rbse68egp9wj9_A@mail.gmail.com
Fixes: 0d80e7f951be ("rqspinlock: Choose trylock fallback for NMI waiters")
Reported-by: Ritesh Oedayrajsingh Varma <ritesh@superluminal.eu>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20251128232802.1031906-2-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
The makefile logic to detect if rust is enabled is not working
the way it was expected: instead of using the current setup
for CONFIG_RUST, it uses a cached version from a previous build.
The root cause is that the current logic inside docs/Makefile
uses a cached version of CONFIG_RUST, from the last time a non
documentation target was executed. That's perfectly fine for
Sphinx build, as it doesn't need to read or depend on any
CONFIG_*.
So, instead of relying at the cache, move the logic to the
wrapper script and let it check the current content of .config,
to verify if CONFIG_RUST was selected.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <c06b1834ef02099735c13ee1109fa2a2b9e47795.1763722971.git.mchehab+huawei@kernel.org>
|
|
Reorganize README to provide targeted documentation paths for different user
roles including developers, researchers, security experts, and maintainers.
Add quick start section and essential docs links.
Signed-off-by: Sasha Levin <sashal@kernel.org>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: SeongJae Park <sj@kernel.org>
Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20251121180009.2634393-1-sashal@kernel.org>
|
|
Correct grammar, spelling, and punctuation in comments, strings,
print messages, logs.
Change two instances of two spaces between words to just one space.
codespell was used to find misspelled words.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20251124041011.3030571-1-rdunlap@infradead.org>
|
|
kdoc is looking for "@value" here, so use that kind of string in the
warning message. The "%value" can be confusing.
This changes:
Warning: drivers/net/wireless/mediatek/mt76/testmode.h:92 Excess enum value '%MT76_TM_ATTR_TX_PENDING' description in 'mt76_testmode_attr'
to this:
Warning: drivers/net/wireless/mediatek/mt76/testmode.h:92 Excess enum value '@MT76_TM_ATTR_TX_PENDING' description in 'mt76_testmode_attr'
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20251126061752.3497106-1-rdunlap@infradead.org>
|
|
The paragraph mentions only removal of Tested-by and Reviewed-by tags as
action needing mentioning in patch changelog, so some developers treat
it too literally. Acks, as a weaker form of review/approval, should
rarely be removed, but if that happens it should be explained as well.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20251126081905.7684-2-krzysztof.kozlowski@oss.qualcomm.com>
|
|
Recognize and ignore __rcu (in struct members), __private (in struct
members), and __always_unused (in function parameters) to prevent
kernel-doc warnings:
Warning: include/linux/rethook.h:38 struct member 'void (__rcu *handler' not described in 'rethook'
Warning: include/linux/hrtimer_types.h:47 Invalid param: enum hrtimer_restart (*__private function)(struct hrtimer *)
Warning: security/ipe/hooks.c:81 function parameter '__always_unused' not described in 'ipe_mmap_file'
Warning: security/ipe/hooks.c:109 function parameter '__always_unused' not described in 'ipe_file_mprotect'
There are more of these (in compiler_types.h, compiler_attributes.h)
that can be added as needed.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20251127063117.150384-1-rdunlap@infradead.org>
|
|
Update Mauro's F: (files/paths) entry for docs scripts so that
get_maintainer.pl will report these correctly.
This is copied from Jon's entries for these paths.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20251127063125.150441-1-rdunlap@infradead.org>
|
|
gitolite.kernel.org:pub/scm/linux/kernel/git/alexs/linux into tmp
Chinese translation docs for 6.19
This is the Chinese translation subtree for 6.19. It includes
the following changes:
- Add block part translations
- Update kbuild.rst translations
- Add more scsi translations and fixes
Above patches are tested by 'make htmldocs'
Signed-off-by: Alex Shi <alexs@kernel.org>
|
|
Raw NAND changes:
* The major change in this MR will be the support for the Allwinner H616
NAND controller, which lead to numerous changes and cleanups in the
driver.
* Another notable change on this driver is the use of
field_get()/field_prep(), but since the global support for this
helpers is going to be merged in the same release as we start using
these helpers, it implies undefining them in the first place to avoid
warnings. Depending on the merging order (Yuri's bitmap branch or
mtd/next), a temporary warning may arise.
* Marvell drivers layout handling changes have also landed, they fix
previous definitions and abuses that have been made previously, which
implied to relax the ECC parameters validation in the core a bit.
* The Cadence NAND controller driver gets NV-DDR interface support.
SPI NAND changes:
* Support for FudanMicro FM25S01BI3 and ESMT F50L1G41LC is added.
Aside from these main changes, there is the usual load of fixes and API
updates.
|
|
https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux into mtd/next
SPI NOR changes for 6.19
Notable changes:
- Fix SMPT parsing for S25FS-S flash family. They report variable dummy
cycles for reads. This results in the default of 0 being used. This
works for other Infineon chips, but not for the S25FS-S family. They
need 8 dummy cycles. Add fixup hooks to specify that. Also add fixup
hooks to fix incorrect map ID data in SFDP.
- Add support for a bunch of Winbond flashes. Their block protection
information is not discoverable, so they need to have an entry in the
flash tables to describe that.
- Some cleanups for Micron flash support.
- Add support for Micron mt35xu01gbba.
- Some SPI controllers like the Intel one on the PCI bus do not support
the read CR opcode (0x35). Do not use the opcode if the controller
does not support it.
# -----BEGIN PGP SIGNATURE-----
#
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# CfGsAQC5Vj+FaeQHyY+yywqM5wxE+xj6mMCDNixd2FVYlf5b7wEA2/9bpiHjy3qi
# 4MZmFJNcE+XsxReWDTBTZ6VbrjDlqg0=
# =M+s4
# -----END PGP SIGNATURE-----
# gpg: Signature made jeu. 27 nov. 2025 23:26:01 CET
# gpg: using EDDSA key 1395458DCD7184A376C59B2211E1DAEA3F4DBC09
# gpg: Good signature from "Pratyush Yadav <p.yadav@ti.com>" [expired]
# gpg: aka "Pratyush Yadav <me@yadavpratyush.com>" [expired]
# gpg: p.yadav@ti.com: Verified 5 signatures in the past 3 years. Encrypted 0 messages.
# gpg: me@yadavpratyush.com: Verified 5 signatures in the past 3 years. Encrypted
# 0 messages.
# gpg: Note: This key has expired!
# Primary key fingerprint: 805C 3923 2FBE 108C 49E1 663C F650 3556 C11B 1CCD
# Subkey fingerprint: 1395 458D CD71 84A3 76C5 9B22 11E1 DAEA 3F4D BC09
|
|
s/is/if/
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
|
|
strncpy() is deprecated [1] for NUL-terminated destination buffers
because it does not guarantee NUL termination. It also unnecessarily
NUL-pads the destination buffer if the source is shorter. Replace it
with sysfs_emit() using the "%.*s" format specifier and supply the
length 'sm_attr->len' to improve sm_attr_show().
Return the number of characters actually written to 'buf' instead of
'sm_attr->len'.
Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
|
|
There are several places where a value of type 'int' is shifted by
lpddr->chipshift. lpddr->chipshift is derived from QINFO geometry and
might reach 31 when QINFO reports a 2 GiB size - the maximum supported by
LPDDR(1) compliant chips. This may cause unexpected sign-extensions when
casting the integer value to the type of 'unsigned long'.
Use '1UL << lpddr->chipshift' and cast 'j' to unsigned long before
shifting so the computation is performed at the destination width.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Fixes: c68264711ca6 ("[MTD] LPDDR Command set driver")
Signed-off-by: Ivan Stepchenko <sid@itb.spb.ru>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
|
|
Fix kernel-doc warnings in docg3.h to avoid build warnings:
Warning: ../drivers/mtd/devices/docg3.h:276 bad line:
Warning: drivers/mtd/devices/docg3.h:299 struct member 'max_block' not
described in 'docg3'
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
|
|
Add support for FudanMicro FM25S01BI3 SPI NAND.
Link: https://www.fmsh.com/nvm/FM25S01BI3_ds_eng.pdf
Signed-off-by: Mikhail Zhilkin <csharper2005@gmail.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
|
|
Change an empty line into a blank kernel-doc line to prevent
a kernel-doc warning:
Warning: ../include/uapi/linux/i2c.h:38 bad line:
Fixes: bfb3939c51d5 ("i2c: refactor documentation of struct i2c_msg")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
|
|
In the past, the i2c-elektor driver was broken on SMP. Since then, there
appear to have been some fixes and cleanup work (as pointed out by Wolfram
Sang) to get rid of cli/sti usage and rely on spinlocks instead. Therefore,
let's allow building the driver on SMP kernels again.
I've tested this driver on an SMP kernel on an Alpha UP2000+ for a few days
without any problems.
Signed-off-by: Magnus Lindholm <linmag7@gmail.com>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
|
