| Age | Commit message (Collapse) | Author |
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Currently, there are 2 kernel cmdline ways to setup numa cma area:
"cma_pernuma=" and "numa_cma=", and there are 2 cma arrays as well,
while they have no difference technically. Robin suggested to cleanup
the code and only use one array [1], as "the apparent intent that
users only want one _or_ the other".
Simplify the code by only using one array to save the numa cma area.
And in rare case that a user really setup the 2 cmdline parameters
at the same time, let the per-node specific size setting 'numa_cma='
take priority over the global numa cma setting.
Link[1]: https://lore.kernel.org/lkml/43c5301c-fe6a-41e4-9482-ccfc7b62f2a7@arm.com/
Suggested-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Feng Tang <feng.tang@linux.alibaba.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20260525015111.6267-1-feng.tang@linux.alibaba.com
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A deadlock occurs in the audit subsystem when duplicating
executable-related rules.
When a file is moved (e.g., via do_renameat2()), the VFS layer locks
the parent directory (I_MUTEX_PARENT), which synchronously triggers an
fsnotify_move event. If an existing executable audit rule matches the
file being moved, the audit subsystem catches this event and calls
audit_dupe_exe() to duplicate the watch and update the rule. Then,
audit_alloc_mark() would call kern_path_parent() to resolve the path,
leading to a blind attempt to acquire the exact same I_MUTEX_PARENT lock
already held by the task, resulting in the following recursive locking
deadlock:
============================================
WARNING: possible recursive locking detected
6.12.0-55.27.1.el10_0.x86_64+debug #1 Not tainted
--------------------------------------------
mv/5099 is trying to acquire lock:
ffff888132845358 (&inode->i_sb->s_type->i_mutex_dir_key/1){+.+.}-{3:3},
at: __kern_path_locked+0x10a/0x2f0
but task is already holding lock:
ffff888132846b58 (&inode->i_sb->s_type->i_mutex_dir_key/1){+.+.}-{3:3},
at: lock_two_directories+0x13f/0x2b0
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(&inode->i_sb->s_type->i_mutex_dir_key/1);
lock(&inode->i_sb->s_type->i_mutex_dir_key/1);
*** DEADLOCK ***
May be due to missing lock nesting notation
6 locks held by mv/5099:
#0: ffff888112a9c440 (sb_writers#13)
at: do_renameat2+0x34c/0xbc0
#1: ffff888112a9c790 (&type->s_vfs_rename_key#3)
at: do_renameat2+0x415/0xbc0
#2: ffff888132846b58 (&inode->i_sb->s_type->i_mutex_dir_key/1)
at: lock_two_directories+0x13f/0x2b0
#3: ffff888132845358 (&inode->i_sb->s_type->i_mutex_dir_key/5)
at: lock_two_directories+0x175/0x2b0
#4: ffffffffb3a1fb10 (&fsnotify_mark_srcu)
at: fsnotify+0x454/0x28a0
#5: ffffffffaf886230 (audit_filter_mutex)
at: audit_update_watch+0x36/0x11e0
stack backtrace:
Call Trace:
<TASK>
dump_stack_lvl+0x6f/0xb0
print_deadlock_bug.cold+0xbd/0xca
validate_chain+0x83a/0xf00
__lock_acquire+0xcac/0x1d20
lock_acquire.part.0+0x11b/0x360
down_write_nested+0x9f/0x230
__kern_path_locked+0x10a/0x2f0
kern_path_locked+0x26/0x40
audit_alloc_mark+0xfb/0x4f0
audit_dupe_exe+0x6c/0xe0
audit_dupe_rule+0x6c2/0xc00
audit_update_watch+0x4cc/0x11e0
audit_watch_handle_event+0x12c/0x1b0
send_to_group+0x5d0/0x8b0
fsnotify+0x615/0x28a0
fsnotify_move+0x1d8/0x630
vfs_rename+0xdcd/0x1df0
do_renameat2+0x9d4/0xbc0
__x64_sys_renameat+0x192/0x260
do_syscall_64+0x92/0x180
entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f0491fe8c4e
Code: 0f 1f 40 00 48 8b 15 c1 e1 16 00 f7 d8 64 89 02 b8 ff ff ff ff
c3 66 0f 1f 44 00 00 f3 0f 1e fa 49 89 ca b8 08 01 00 00 0f 05 <48>
3d 00 f0 ff ff 77 0a c3 66 0f 1f 84 00 00 00 00 00 48 8b 15 89
RSP: 002b:00007ffc7210bf38 EFLAGS: 00000246 ORIG_RAX: 0000000000000108
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f0491fe8c4e
RDX: 0000000000000003 RSI: 00007ffc7210e6c8 RDI: 00000000ffffff9c
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001
R10: 00005575eb2dae2a R11: 0000000000000246 R12: 00005575eb2dae2a
R13: 00007ffc7210e6c8 R14: 0000000000000003 R15: 00000000ffffff9c
</TASK>
The aforementioned deadlock can be consistently reproduced by running
the script below:
audit-dupe-exe-deadlock.sh
--------------------------
#!/bin/bash
auditctl -D
mkdir -p /tmp/foo
touch /tmp/file
auditctl -a always,exit -F exe=/tmp/file -F path=/tmp/file -S all -k dr
mv /tmp/file /tmp/foo/file
rm -Rf /tmp/foo
This patch fixes the issue by introducing struct audit_watch_ctx to pass
the fsnotify event context down to audit_alloc_mark(). By utilizing the
already-resolved directory inode provided by the event, we bypass the
kern_path_parent() path resolution entirely, safely avoiding the
recursive lock. Furthermore, it explicitly allows duplicate fsnotify
marks (allow_dups = 1) during the rename update, allowing the new rule's
mark to safely coexist with the old rule's mark until the old rule is
freed.
P.S.: This issue was identified and reproduced during a comprehensive
code coverage analysis of the audit subsystem. The full report is
available at the link below:
https://people.redhat.com/rrobaina/audit-code-coverage-analysis.pdf
P.P.S: With the permission of both Ricardo and Nathan, I've squashed a
fixup patch from Nathan that addresses a compile time error when
CONFIG_AUDITSYSCALL=n.
Cc: stable@kernel.org
Fixes: 34d99af52ad4 ("audit: implement audit by executable")
Acked-by: Waiman Long <longman@redhat.com>
Acked-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Ricardo Robaina <rrobaina@redhat.com>
[PM: move link metadata into the msg, apply fix from NC]
Signed-off-by: Paul Moore <paul@paul-moore.com>
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On configs with CONFIG_BPF=y but CONFIG_BPF_SYSCALL=n (e.g. arm
multi_v7_defconfig), kernel/bpf/core.c defines a __weak
bpf_arena_handle_page_fault() while bpf_defs.h already supplies a static
inline stub for it, causing a redefinition error. Build the __weak
definition only under CONFIG_BPF_SYSCALL, matching the bpf_defs.h
declaration and the CONFIG_BPF_SYSCALL-gated strong definition in arena.c.
Fixes: dc11a4dba246 ("bpf: Recover arena kernel faults with scratch page")
Reported-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20260527192632.2109419-1-tj@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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When sibling CPU exclusion occurs, a partition's user_xcpus may contain
CPUs that were never actually granted to it. These CPUs are present in
user_xcpus(cs) but not in cs->effective_xcpus.
The partcmd_update path in update_parent_effective_cpumask() uses
user_xcpus(cs) (via the local variable xcpus) to compute the addmask
(CPUs to return to parent) and delmask (CPUs to request from parent).
This is incorrect:
1) When newmask removes a CPU that was previously excluded by a
sibling, addmask incorrectly includes that CPU and tries to return
it to the parent even though the partition never actually owned it,
causing CPU overlap with sibling partitions and triggering warnings
in generate_sched_domains().
2) When newmask adds a previously excluded CPU that is now available,
delmask fails to request it from the parent because user_xcpus(cs)
already includes it.
Fix this by using cs->effective_xcpus instead of user_xcpus(cs) in all
partcmd_update paths that calculate addmask or delmask, including the
PERR_NOCPUS error handling paths.
Reproducers:
Example 1 - Removing a sibling-excluded CPU incorrectly returns it:
# cd /sys/fs/cgroup
# echo "0-1" > a1/cpuset.cpus
# echo "root" > a1/cpuset.cpus.partition
# echo "0-2" > b1/cpuset.cpus
# echo "root" > b1/cpuset.cpus.partition
# echo "2" > b1/cpuset.cpus
# cat cpuset.cpus.effective
# Actual: 0-1,3 Expected: 3
Example 2 - Expanding to a previously excluded CPU fails to request it:
# cd /sys/fs/cgroup
# echo "0-1" > a1/cpuset.cpus
# echo "root" > a1/cpuset.cpus.partition
# echo "0-2" > b1/cpuset.cpus
# echo "root" > b1/cpuset.cpus.partition
# echo "member" > a1/cpuset.cpus.partition
# echo "1-2" > b1/cpuset.cpus
# cat cpuset.cpus.effective
# Actual: 0-1,3 Expected: 0,3
Fixes: 2a3602030d80 ("cgroup/cpuset: Don't invalidate sibling partitions on cpuset.cpus conflict")
Cc: stable@vger.kernel.org # v7.0+
Suggested-by: Zhang Guopeng <zhangguopeng@kylinos.cn>
Signed-off-by: Sun Shaojie <sunshaojie@kylinos.cn>
Reviewed-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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print_worker_info() declares its local 'fn' as work_func_t * but
worker->current_func has type work_func_t (a function pointer). The
extra level of indirection is wrong and only happens to be harmless
today because every supported Linux architecture has
sizeof(work_func_t) == sizeof(work_func_t *):
copy_from_kernel_nofault() reads the correct number of bytes by
accident, and %ps still resolves the printed address because the
stored value is the function address regardless of declared type.
On any future ABI where sizeof(void (*)()) differs from
sizeof(void *), the nofault copy would transfer the wrong number of
bytes and the subsequent %ps would print an incorrect address.
Match the field type so the intent is explicit and the code does not
silently rely on equal pointer sizes.
Fixes: 3d1cb2059d93 ("workqueue: include workqueue info when printing debug dump of a worker task")
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
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|| is a boolean operator, any nonzero (error) return short-circuits
to 1 rather than the actual errno. The caller in scx_init() logs and
propagates this value, so the wrong code reaches upper layers.
Signed-off-by: Cheng-Yang Chou <yphbchou0911@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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When an audited executable is deleted from the disk, its dentry
becomes negative. Any later attempt to delete the associated audit
rule will lead to audit_alloc_mark() encountering this negative
dentry and immediately aborting, returning -ENOENT.
This early abort prevents the subsystem from allocating the temporary
fsnotify mark needed to construct the search key, meaning the kernel
cannot find the existing rule in its own lists to delete it. This
leaves a dangling rule in memory, resulting in the following error
while attempting to delete the rule:
# ./audit-dupe-exe-deadlock.sh
No rules
Error deleting rule (No such file or directory)
There was an error while processing parameters
# auditctl -l
-a always,exit -S all -F exe=/tmp/file -F path=/tmp/file -F key=dr
# auditctl -D
Error deleting rule (No such file or directory)
There was an error while processing parameters
This patch fixes this issue by removing the d_really_is_negative()
check. By doing so, a dummy mark can be successfully generated for
the deleted path, which allows the audit subsystem to properly match
and flush the dangling rule.
Cc: stable@kernel.org
Fixes: 76a53de6f7ff ("VFS/audit: introduce kern_path_parent() for audit")
Acked-by: Waiman Long <longman@redhat.com>
Acked-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Ricardo Robaina <rrobaina@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Address checkpatch.pl warning below, across the audit subsystem:
WARNING: Prefer 'unsigned int' to bare use of 'unsigned'
Minor cleanup, no functional changes.
Signed-off-by: Ricardo Robaina <rrobaina@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull misc fixes from Andrew Morton:
"13 hotfixes. 9 are for MM. 9 are cc:stable and the remaining 4 address
post-7.1 issues or aren't considered suitable for backporting.
All patches are singletons - please see the individual changelogs for
details"
* tag 'mm-hotfixes-stable-2026-05-25-16-22' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
Revert "mm: introduce a new page type for page pool in page type"
mm/vmalloc: do not trigger BUG() on BH disabled context
MAINTAINERS, mailmap: change email for Eugen Hristev
mm/migrate_device: fix pgtable leak in migrate_vma_insert_huge_pmd_page
kernel/fork: validate exit_signal in kernel_clone()
mm: memcontrol: propagate NMI slab stats to memcg vmstats
mm/damon/sysfs-schemes: delete tried region in regions_rmdirs()
mm/rmap: initialize nr_pages to 1 at loop start in try_to_unmap_one
zram: fix use-after-free in zram_writeback_endio
memfd: deny writeable mappings when implying SEAL_WRITE
ipc: limit next_id allocation to the valid ID range
Revert "mm/hugetlbfs: update hugetlbfs to use mmap_prepare"
MAINTAINERS: .mailmap: update after GEHC spin-off
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Reading /proc/interrupts iterates over the interrupt number space one by
one and looks up the descriptors one by one. That's just a waste of time.
When CONFIG_GENERIC_IRQ_SHOW is enabled this can utilize the maple tree and
cache the descriptor pointer efficiently for the sequence file operations.
Implement a CONFIG_GENERIC_IRQ_SHOW specific version in the core code and
leave the fs/proc/ variant for the legacy architectures which ignore generic
code.
This reduces the time wasted for looking up the next record significantly.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Reviewed-by: Dmitry Ilvokhin <d@ilvokhin.com>
Link: https://patch.msgid.link/20260517194932.165280601@kernel.org
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The chip name column in the /proc/interrupt output is 8 characters and
right aligned, which causes visual clutter due to the fixed length and the
alignment. Many interrupt chips, e.g. PCI/MSI[X] have way longer names.
Update the length when a chip is assigned to an interrupt and utilize this
information for the output. Align it left so all chip names start at the
begin of the column.
Update the GDB script as well and disentangle the header maze so it
actually works with all .config combinations.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Reviewed-by: Dmitry Ilvokhin <d@ilvokhin.com>
Link: https://patch.msgid.link/20260517194932.085786035@kernel.org
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... in preparation for a smarter iterator for /proc/interrupts.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Reviewed-by: Dmitry Ilvokhin <d@ilvokhin.com>
Link: https://patch.msgid.link/20260517194932.005787611@kernel.org
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Prepare for a smarter iterator for /proc/interrupts so that the next
interrupt descriptor can be cached after lookup.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Reviewed-by: Dmitry Ilvokhin <d@ilvokhin.com>
Link: https://patch.msgid.link/20260517194931.917415190@kernel.org
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Quite some architectures have four character wide acronyms for architecture
specific interrupts like IPI, NMI, etc.
The default precision of printing the Linux device interrupt numbers is
three, which causes quite some code to play games with adding or omitting
space after the acronym and the colon in order to keep the per CPU numbers
properly aligned.
Increase the default number precision to four in the core code and get rid
of the space games all over the place. At the same time align all
architecture specific descriptor texts left so that they show up in the
same column as the interrupt chip names, which makes the output more
uniform accross architectures. Fix up the GDB script to this new scheme as
well.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260517194931.839482411@kernel.org
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Calculating the precision of the interrupt number column on every initial
show_interrupt() invocation is a pointless exercise as the underlying
maximum number of interrupts rarely changes.
Calculate it only when that number is modified and let show_interrupts()
use the cached value.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Reviewed-by: Dmitry Ilvokhin <d@ilvokhin.com>
Reviewed-by: Radu Rendec <radu@rendec.net>
Link: https://patch.msgid.link/20260517194931.760664517@kernel.org
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show_interrupts() evaluates a boatload of conditions to establish whether
it should expose an interrupt in /proc/interrupts or not.
That can be simplified by caching the condition in an internal status flag,
which is updated when one of the relevant inputs changes.
The irq_desc::kstat_irq check is dropped because visible interrupt
descriptors always have a valid pointer.
As a result the number of instructions and branches for reading
/proc/interrupts is reduced significantly.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Reviewed-by: Dmitry Ilvokhin <d@ilvokhin.com>
Reviewed-by: Radu Rendec <radu@rendec.net>
Link: https://patch.msgid.link/20260517194931.680943749@kernel.org
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Eventually blocking functions cannot be invoked with interrupts disabled
and a raw spin lock held. Restructure the code so this happens outside of
the descriptor lock held region.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Link: https://patch.msgid.link/20260517194931.601972758@kernel.org
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... to avoid function calls in the core code to retrieve the maximum number
of interrupts.
Rename it to 'total_nr_irqs' as 'nr_irqs' is too generic and fix up the
'nr_irqs' reference in the related GDB script as well.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Reviewed-by: Dmitry Ilvokhin <d@ilvokhin.com>
Reviewed-by: Radu Rendec <radu@rendec.net>
Reviewed-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Link: https://patch.msgid.link/20260517194931.522168332@kernel.org
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Interrupts which are not marked per CPU increment not only the per CPU
statistics, but also the accumulation counter irq_desc::tot_count.
Change the counter to type unsigned long so it does not produce sporadic
zeros due to wrap arounds on 64-bit machines and do a quick check for non
per CPU interrupts. If the counter is zero, then simply emit a full set of
zero strings. That spares the evaluation of the per CPU counters completely
for interrupts with zero events.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Reviewed-by: Dmitry Ilvokhin <d@ilvokhin.com>
Reviewed-by: Radu Rendec <radu@rendec.net>
Link: https://patch.msgid.link/20260517194931.115522199@kernel.org
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A large portion of interrupt count entries are zero. There is no point in
formatting the zero value as it is way cheeper to just emit a constant
string.
Collect the number of consecutive zero counts and emit them in one go
before a non-zero count and at the end of the line.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Reviewed-by: Dmitry Ilvokhin <d@ilvokhin.com>
Reviewed-by: Radu Rendec <radu@rendec.net>
Reviewed-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Link: https://patch.msgid.link/20260517194931.034728540@kernel.org
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The CRC uncompressed buffer pointer array has the same lifetime as
struct crc_data, but it is currently allocated separately. That adds
another allocation failure path and a matching cleanup branch without
providing any extra flexibility.
Store the pointer array as a flexible array member and allocate it
together with the crc_data using kzalloc_flex(). The array remains
zero-initialized, while the allocation and error handling become
simpler.
Assisted-by: Codex:GPT-5.5
Signed-off-by: Rosen Penev <rosenp@gmail.com>
Link: https://patch.msgid.link/20260510213948.41750-1-rosenp@gmail.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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The reason for pick_next_task_fair() is the put/set optimization that
avoids touching the common ancestors. However, it is possible to
implement this in the put_prev_task() and set_next_task() calls as
used in put_prev_set_next_task().
Notably, put_prev_set_next_task() is the only site that:
- calls put_prev_task() with a .next argument;
- calls set_next_task() with .first = true.
This means that put_prev_task() can determine the common hierarchy and
stop there, and then set_next_task() can terminate where put_prev_task
stopped.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://patch.msgid.link/20260511120628.057634261@infradead.org
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With commit 50653216e4ff ("sched: Add support to pick functions to
take rf") removing the balance callback, the pick_task() callback is
in charge of newidle balancing.
This means pick_task_fair() should do so too. This hasn't been a
problem in practise because pick_next_task_fair() is used. However,
since we'll be removing that one shortly, make sure pick_next_task()
is up to scratch.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://patch.msgid.link/20260511120627.944705718@infradead.org
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Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260511120627.281160085@infradead.org
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Robots figured out you can read and write this concurrently and got
'upset'. Gemini even noted sched_dynamic_show() can generate
'confusing' output if it observed different values during the
printing.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260511120627.176946327@infradead.org
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Some of the fancy AI robots are getting 'upset'.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260511120627.065013766@infradead.org
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Commit c9d93a73ce87 ("sched/fair: Drop redundant RCU read lock in NOHZ
kick path") removed the rcu_read_lock()/unlock() pair from
set_cpu_sd_state_busy() and set_cpu_sd_state_idle() on the assumption
that all callers run in a safe context for rcu_dereference_all(): IRQs
disabled or cpus_write_lock() held.
That assumption is wrong for the CPU hotplug teardown path. When CPUs
are taken offline, set_cpu_sd_state_busy() is invoked via:
cpuhp/N kthread
cpuhp_thread_fun()
cpuhp_invoke_callback()
sched_cpu_deactivate()
nohz_balance_exit_idle()
set_cpu_sd_state_busy()
rcu_dereference_all(per_cpu(sd_llc, cpu))
The cpuhp kthread holds cpu_hotplug_lock (percpu-rwsem) but runs with
preemption and IRQs enabled. As a result, lockdep correctly reports a
suspicious RCU usage on CPU offline, e.g.:
# echo 0 > /sys/devices/system/cpu/cpu1/online
=============================
WARNING: suspicious RCU usage
-----------------------------
kernel/sched/fair.c:12793 suspicious rcu_dereference_check() usage!
...
2 locks held by cpuhp/1/20:
#0: (cpu_hotplug_lock){++++}-{0:0}, at: cpuhp_thread_fun+0x42/0x1ae
#1: (cpuhp_state-down){+.+.}-{0:0}, at: cpuhp_thread_fun+0x72/0x1ae
Call Trace:
lockdep_rcu_suspicious
nohz_balance_exit_idle
sched_cpu_deactivate
cpuhp_invoke_callback
cpuhp_thread_fun
smpboot_thread_fn
Fix this by adding RCU read lock coverage to the one caller that lacks
it: nohz_balance_exit_idle() in the CPU hotplug teardown.
The other callers (nohz_balancer_kick() and nohz_balance_enter_idle())
genuinely run with IRQs disabled, so they remain unchanged.
Fixes: c9d93a73ce87 ("sched/fair: Drop redundant RCU read lock in NOHZ kick path")
Closes: https://lore.kernel.org/all/38fe0a1d-1a48-435a-910a-c278024d9ac9@samsung.com/
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260522092523.2046095-1-arighi@nvidia.com
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Without this, CRYPTO_LZ4 had to be manually enabled in the config
to use LZ4 for hibernation compression. Add the select so it gets
pulled in automatically when hibernation is enabled, just like
CRYPTO_LZO already does.
Tested-by: l1rox3 <l1rox3.developer@gmail.com>
Signed-off-by: l1rox3 <l1rox3.developer@gmail.com>
Link: https://patch.msgid.link/20260520081254.13493-1-l1rox3.developer@gmail.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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The dumpable flag captured at execve() is consulted by
__ptrace_may_access() and several /proc owner / visibility checks.
It lives on mm_struct today, which exit_mm() clears from the task
long before the task itself is reaped.
exec_state is anchored to the execve() that established the current
privilege domain. CLONE_VM siblings refcount-share the parent's
exec_state via copy_exec_state(); non-CLONE_VM clones allocate a
fresh exec_state inheriting the parent's dumpable mode and user_ns
reference via task_exec_state_copy(). execve() allocates a fresh
instance (via alloc_task_exec_state() in begin_new_exec()) and
installs it under task_lock + exec_update_lock with
task_exec_state_replace(). init_task uses a static instance.
The dumpable mode now lives on task->exec_state->dumpable.
task->mm->flags no longer carries dumpability; MMF_DUMPABLE_MASK is
removed, but MMF_DUMPABLE_BITS is reserved so MMF_DUMP_FILTER_* bit
positions remain stable for the /proc/<pid>/coredump_filter ABI. The
task->user_dumpable cache bit and its assignment in exit_mm() are
removed; readers go through get_dumpable(task) directly.
coredump_params gains a snapshot field cprm.dumpable, populated from
get_dumpable(current) at vfs_coredump() entry, replacing the previous
__get_dumpable(cprm->mm_flags) consumers in fs/coredump.c and
fs/pidfs.c.
The user namespace recorded at execve() is consulted by
__ptrace_may_access() and by /proc/PID/* owner derivation. Move the
captured user_ns onto task_exec_state, which stays attached to the task
past exit_mm() and across exit_files().
bprm grows a user_ns field staged in bprm_mm_init() with the caller's
user_ns, narrowed by would_dump() to the closest privileged ancestor,
and consumed by exec_mmap() via alloc_task_exec_state(bprm->user_ns).
free_bprm() releases the staging reference.
mm_struct loses ->user_ns entirely. Initializers in init-mm, efi_mm,
and the implicit one in mm_init()/dup_mm()/mm_alloc() are removed;
__mmdrop() drops the matching put_user_ns(). The kthread_use_mm()
WARN_ON_ONCE(!mm->user_ns) is no longer meaningful and goes too.
Reviewed-by: Jann Horn <jannh@google.com>
Link: https://patch.msgid.link/20260520-work-task_exec_state-v3-4-69f895bc1385@kernel.org
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
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Add a helper that encapsulates all of the logic for checking ptrace
access and remove open-coded versions in follow-up patches.
Reviewed-by: Jann Horn <jannh@google.com>
Reviewed-by: David Hildenbrand (arm) <david@kernel.org>
Link: https://patch.msgid.link/20260520-work-task_exec_state-v3-3-69f895bc1385@kernel.org
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
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Introduce struct task_exec_state, a per-task RCU-protected structure
that holds the dumpable mode and the user namespace and stays attached
to the task for its full lifetime.
task_exec_state_rcu() is the canonical reader: asserts RCU or
task_lock is held, WARNs on a NULL state, returns the
rcu_dereference()'d pointer.
Reviewed-by: Jann Horn <jannh@google.com>
Link: https://patch.msgid.link/20260520-work-task_exec_state-v3-2-69f895bc1385@kernel.org
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
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Replace the SUID_DUMP_DISABLE/USER/ROOT preprocessor constants with
enum task_dumpable. Numeric values are preserved (kernel.suid_dumpable
sysctl and prctl(PR_SET_DUMPABLE) ABI), so this is a pure rename with
no behavioral change.
Subsequent commits relocate dumpability onto a per-task structure
where the enum type will allow stronger type-checking on the new API.
Reviewed-by: Jann Horn <jannh@google.com>
Reviewed-by: David Hildenbrand (arm) <david@kernel.org>
Link: https://patch.msgid.link/20260520-work-task_exec_state-v3-1-69f895bc1385@kernel.org
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
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Commit 91e74fa8b1bc ("kho: make sure preservations do not span multiple
NUMA nodes") made sure preservations from kho_preserve_pages() do not
span multiple NUMA nodes. If they do, the order is reduced and tried
again.
The same logic was not implemented for kho_unpreserve_pages(). This can
result in unpreserve calculating a different order than preserve, and
thus not actually unpreserving the pages.
Fix this by moving the order calculation logic to
__kho_preserve_pages_order() and use it from both preserve and
unpreserve paths.
Move __kho_unpreserve() down to avoid having a forward declaration. Its
users are further down in the file anyway. Also, it results in grouping
for all the page-level preservation and unpreservation functions. This
unfortunately makes the diff hard to read, but the main change in
__kho_unpreserve() is to call __kho_preserve_pages_order() instead of
open-coding the order calculation.
Fixes: 91e74fa8b1bc ("kho: make sure preservations do not span multiple NUMA nodes")
Cc: stable@vger.kernel.org
Signed-off-by: Pratyush Yadav (Google) <pratyush@kernel.org>
Reviewed-by: Samiullah Khawaja <skhawaja@google.com>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Link: https://patch.msgid.link/20260519133332.2498092-1-pratyush@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
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ops_cid.set_cmask() expects a cmask. The kernel couldn't write into the
arena, so it translated cpumask -> cmask in kernel memory and passed the
result as a trusted pointer. The BPF cmask helpers all operate on arena
cmasks though, so the BPF side had to word-by-word probe-read the kernel
cmask into an arena cmask via cmask_copy_from_kernel() before any helper
could touch it. It works, but is clumsy.
With direct kernel-side arena access now in place, build the cmask in the
arena. The kernel writes to it through the kern_va side of the dual mapping.
BPF directly dereferences it via an __arena pointer like any other arena
struct.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
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Build a per-scheduler sub-allocator on top of pages claimed from the BPF
arena registered in the previous patch. Subsequent kernel-managed
arena-resident structures (e.g. per-CPU set_cmask cmask) carve their storage
from this pool.
scx_arena_pool_init() creates a gen_pool. scx_arena_alloc() returns the
kernel VA. On exhaustion, the pool grows by claiming more pages via
bpf_arena_alloc_pages_sleepable(). Chunks are added at the kernel-side
mapping address. Callers translate to the BPF-arena form themselves if
needed.
Allocations sleep (GFP_KERNEL) - they may grow the pool through vzalloc and
arena page allocation. All current consumers run from the enable path (after
ops.init() and the kernel-side arena auto-discovery, before validate_ops()),
where sleeping is fine.
scx_arena_pool_destroy() walks each chunk, returns outstanding ranges to the
gen_pool with gen_pool_free() and then calls gen_pool_destroy(). The
underlying arena pages are released when the arena map itself is torn down,
so the pool destroy doesn't free them explicitly.
v2: Switch scx_arena_alloc() to a loop. (Andrea)
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Andrea Righi <arighi@nvidia.com>
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Upcoming patches will let the kernel place arena-resident scratch shared
with the BPF program (e.g. per-CPU set_cmask cmask) so the BPF side can
dereference it directly via __arena pointers, replacing the current
cmask_copy_from_kernel() probe-read loop. That requires each cid-form
scheduler to expose its arena to the kernel. Kernel- side accesses are
recovered by the per-arena scratch-page mechanism.
bpf_scx_reg_cid() walks the struct_ops member progs via
bpf_struct_ops_for_each_prog() and reads each prog's arena via
bpf_prog_arena(). The verifier enforces one arena per program, so each
member prog contributes at most one arena. All non-NULL contributions must
match and at least one member prog must use an arena. The map ref is held on
scx_sched and dropped on sched destroy. cpu-form schedulers (bpf_scx_reg)
are unchanged - no arena requirement.
Signed-off-by: Tejun Heo <tj@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next into for-7.2
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Tejun Heo says:
====================
This makes BPF arena memory directly dereferenceable from kernel code
(struct_ops callbacks, kfuncs). Each arena gets a per-arena scratch page
that an arch fault hook installs into empty PTEs on kernel-side faults,
after KFENCE. The faulting instruction retries and the violation is reported
through the program's BPF stream.
v4:
- Patch 1: note that the strict-zero cmpxchg is narrower than pte_none() in
inline comments on both x86 and arm64. (Andrea)
- Patch 2: stub bpf_arena_handle_page_fault() for !CONFIG_BPF_SYSCALL via a
new include/linux/bpf_defs.h. (lkp)
- Patch 7: scx_arena_alloc() retries via a loop instead of a single retry on
pool growth. (Andrea)
- Picked up Reviewed-by tags from Emil and Andrea.
v3: https://lore.kernel.org/r/20260520235052.4180316-1-tj@kernel.org
v2: https://lore.kernel.org/r/20260517211232.1670594-1-tj@kernel.org
v1 (RFC): https://lore.kernel.org/r/20260427105109.2554518-1-tj@kernel.org
Motivation
----------
sched_ext's ops_cid.set_cmask() hands the BPF scheduler a struct scx_cmask
*. The kernel translates a kernel cpumask to a cmask, but it had no way to
write into the arena, so the cmask lived in kernel memory and was passed as
a trusted pointer. BPF cmask helpers all operate on arena cmasks though, so
the BPF side had to word-by-word probe-read the kernel cmask into an arena
cmask via cmask_copy_from_kernel() before any helper could touch it. It
works, but is clumsy.
The shape isn't unique to set_cmask. Sub-scheduler support is on the way and
more sched_ext callbacks will want to pass structured data to BPF. Anywhere
a kfunc or struct_ops callback wants to hand a struct to a BPF program,
arena residence is the natural answer.
Approach
--------
Each arena gets a per-arena scratch page. Arenas stay sparsely mapped as
today - PTEs are populated only for allocated pages. A new arch fault hook
(bpf_arena_handle_page_fault) is wired into x86 page_fault_oops() and arm64
__do_kernel_fault(), after KFENCE. When a kernel-side access faults inside
an arena's kern_vm range, the helper walks the stack to find the BPF program
responsible, range-checks the fault address against prog->aux->arena, and
atomically installs the scratch page into the empty PTE via the new
ptep_try_set() wrapper. The kernel instruction retries and reads/writes the
scratch page. Free paths and map destruction treat scratch as non-owned.
Real allocation refuses to overwrite scratch (apply_range_set_cb returns
-EBUSY). A scratched address stays dead until map destroy, since its
presence means the BPF program has already malfunctioned.
The mechanism is default behavior - no UAPI flag.
What this preserves
-------------------
All the debugging properties of today's sparse-PTE design are preserved:
* BPF programs still fault on unmapped arena accesses. The fault semantics
(instruction retry with rdst = 0) and the violation report through
bpf_streams are unchanged for prog-side accesses.
* The first kernel-side touch of an unmapped address is reported via
bpf_streams the same way as a prog-side fault, with the stack walk
attributing it to the originating prog.
* User-side fault on a never-scratched address still lazy-allocates a real
page (or returns SIGSEGV under BPF_F_SEGV_ON_FAULT). User-side fault on a
scratched address SIGSEGVs.
What changes for the kernel-side caller is just that an unmapped deref no
longer oopses - it retries through the scratch page and emits a violation
report. The same shape today's BPF instruction faults have.
Patches 1-2 (atomic PTE install + arena scratch-page recovery)
--------------------------------------------------------------
mm: Add ptep_try_set() for lockless empty-slot installs
bpf: Recover arena kernel faults with scratch page
Patches 3-5 (helpers used by struct_ops registration)
-----------------------------------------------------
bpf: Add sleepable variant of bpf_arena_alloc_pages for kernel callers
bpf: Add bpf_struct_ops_for_each_prog()
bpf/arena: Add bpf_arena_map_kern_vm_start() and bpf_prog_arena()
====================
Link: https://lore.kernel.org/bpf/20260522172219.1423324-1-tj@kernel.org/
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Cross-merge BPF and other fixes after downstream PR.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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We need the driver-core fixes in here as well to build on top of.
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
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Pull bpf fixes from Alexei Starovoitov:
- Fix bpf_throw() and global subprog combination (Kumar Kartikeya
Dwivedi)
- Fix out of bounds access in BPF interpreter (Yazhou Tang)
- Fix potential out of bounds access in inner per-cpu array map
(Guannan Wang)
- Reject NULL data/sig in bpf_verify_pkcs7_signature (KP Singh)
* tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
libbpf: fix off-by-one in emit_signature_match jump offset
bpf: Reject NULL data/sig in bpf_verify_pkcs7_signature
selftests/bpf: Cover global subprog exception leaks
bpf: Check global subprog exception paths
bpf: make bpf_session_is_return() reference optional
bpf: Use array_map_meta_equal for percpu array inner map replacement
selftests/bpf: Add test for large offset bpf-to-bpf call
bpf: Fix s16 truncation for large bpf-to-bpf call offsets
bpf: Fix out-of-bounds read in bpf_patch_call_args()
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The following scenarios will cause the call_rcu_tasks() boot-time
tests failed:
CPU0 CPU1
rcu_init_tasks_generic()
->rcu_tasks_initiate_self_tests()
->call_rcu_tasks_trace(&tests[1].rh, test_rcu_tasks_callback)
->call_rcu_tasks_generic()
->havekthread = smp_load_acquire(&rtp->kthread_ptr)
"The havekthread is false"
....
rcu_tasks_kthread()
->smp_store_release(&rtp->kthread_ptr, current)
->rcu_tasks_one_gp()
->rcuwait_wait_event()
->rcu_tasks_need_gpcb()
->for (cpu = 0; cpu < dequeue_limit; cpu++)
->rcu_segcblist_n_cbs(&rtpcp->cblist) == 0
->schedule()
->raw_spin_trylock_rcu_node()
->needwake = (func == wakeme_after_rcu) ||
(rcu_segcblist_n_cbs(&rtpcp->cblist) == rcu_task_lazy_lim)
"the rcu_task_lazy_lim default value is 32, and the
func pointer is test_rcu_tasks_callback, lead to needwake
is false."
->if (havekthread && !needwake && !timer_pending(&rtpcp->lazy_timer))
"the havekthread is false, will not enter here."
....
"the needwake is false lead to rtp_irq_work can not queue,
even if the rtp->kthread_ptr already exists at this point."
->if (needwake && READ_ONCE(rtp->kthread_ptr))
->irq_work_queue(&rtpcp->rtp_irq_work)
For the above scenarios, if the call_rcu_tasks() is not called again
afterward, the rcu_tasks_kthread will not have a chance to be wakeup,
the test_rcu_tasks_callback() will never be called, the boot-time tests
failed can happen, this commit therefore check havekthread variable, if
it's false and the rtpcp->cblist is empty, set needwake variable is true,
if the rtp->kthread_ptr exist, the rtpcp->rtp_irq_work can be queued to
wakeup rcu_tasks_kthread.
Signed-off-by: Zqiang <qiang.zhang@linux.dev>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
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Currently, rcu_normal_wake_from_gp is only enabled by default
on small systems(<= 16 CPUs) or when a user explicitly set it
enabled.
Introduce an adaptive latching mechanism:
* Track the number of in-flight synchronize_rcu() requests
using a new rcu_sr_normal_count counter;
* If the count reaches/exceeds RCU_SR_NORMAL_LATCH_THR(64),
it sets the rcu_sr_normal_latched, reverting new requests
onto the scaled wait_rcu_gp() path;
* The latch is cleared only when the pending requests are fully
drained(nr == 0);
* Enables rcu_normal_wake_from_gp by default for all systems,
relying on this dynamic throttling instead of static CPU
limits.
Testing(synthetic flood workload):
* Kernel version: 6.19.0-rc6
* Number of CPUs: 1536
* 60K concurrent synchronize_rcu() calls
Perf(cycles, system-wide):
total cycles: 932020263832
rcu_sr_normal_add_req(): 2650282811 cycles(~0.28%)
Perf report excerpt:
0.01% 0.01% sync_test/... [k] rcu_sr_normal_add_req
Measured overhead of rcu_sr_normal_add_req() remained ~0.28%
of total CPU cycles in this synthetic stress test.
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Tested-by: Samir M <samir@linux.ibm.com>
Suggested-by: Joel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
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This commit replaces a nested ?: sequence with clamp_val(). This does
not reduce the number of lines of code, but it does simplify the line
that it modifies.
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
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This commit replaces a nested ?: sequence with clamp(). This does not
reduce the number of lines of code, but it does simplify the line that
it modifies.
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
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This new torture_sched_set_normal() function clamps the nice value at
the MIN_NICE..MAX_NICE limits, splatting it these limits are exceeded.
It then invokes sched_set_normal() to set the new value. This prevents
more difficult-to-debug failures within the scheduler.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
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Currently, rcutorture bypasses lazy RCU by using call_rcu_hurry().
This works, avoiding the dreaded rtort_pipe_count WARN(), but fails to
fully test lazy RCU. The rtort_pipe_count WARN() splats because lazy RCU
could delay the start of an RCU grace period for a full stutter period,
which defaults to only three seconds.
This commit therefore reverts the call_rcu_hurry() instances
back to call_rcu(), but, in kernels built with CONFIG_RCU_LAZY=y,
queues a workqueue handler just before the call to stutter_wait() in
rcu_torture_writer(). This workqueue handler invokes rcu_barrier(),
which motivates any lingering lazy callbacks, thus avoiding the splat.
Reported-by: Saravana Kannan <saravanak@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
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struct bpf_arena is opaque to callers outside arena.c. Add two helpers
for struct_ops subsystems that need to reach into an arena:
bpf_arena_map_kern_vm_start(struct bpf_map *map)
returns @map's kern_vm_start. A sched_ext follow-up needs this
to translate kern_va <-> uaddr.
bpf_prog_arena(struct bpf_prog *prog)
returns the bpf_map of the arena referenced by @prog (NULL if
@prog references no arena). The verifier enforces at most one
arena per program. Used by struct_ops callers that auto-discover
an arena from a member prog and need to take a map reference.
Suggested-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Link: https://lore.kernel.org/r/20260522172219.1423324-6-tj@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Add a helper that walks the member progs of the struct_ops map
containing a given @kdata vmtable. struct_ops ->reg() callbacks (and
similar) sometimes need to inspect the loaded BPF programs, e.g. to
discover maps they reference via prog->aux->used_maps.
The implementation mirrors bpf_struct_ops_id(): container_of @kdata
to recover the bpf_struct_ops_map, then iterate st_map->links[i]->prog
for i in [0, funcs_cnt). Same access pattern, no new locking - by the
time ->reg() fires st_map is fully populated and stable.
A sched_ext follow-up walks the member progs of a cid-form scheduler's
struct_ops map, reads prog->aux->arena directly, and requires all member
progs to reference exactly one arena, without requiring the BPF program
to call a registration kfunc.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Link: https://lore.kernel.org/r/20260522172219.1423324-5-tj@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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The existing kernel-side export of bpf_arena_alloc_pages is _non_sleepable
only - it's used by the verifier to inline the kfunc when the call site is
non-sleepable. There is no sleepable equivalent for kernel callers. The
kfunc bpf_arena_alloc_pages itself is BPF-only.
sched_ext needs sleepable kernel-side allocs for its arena pool init/grow
paths. Add bpf_arena_alloc_pages_sleepable() mirroring the _non_sleepable
wrapper but passing sleepable=true to arena_alloc_pages().
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Link: https://lore.kernel.org/r/20260522172219.1423324-4-tj@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
