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Linux 7.3-rc4
Requested by Philipp Stanner for
2ab510e63197360945f915dd5631a77c63ac6b27 would be needed as a groundlayer
for further patches that extend the locking in drm_sched
Signed-off-by: Dave Airlie <airlied@redhat.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer race fixes from Ingo Molnar:
- Fix timer signal <-> exec() race, to prevent UAF (Thomas Gleixner)
- Clean up POSIX CPU timers right after de_thread(), to prevent UAF
(Hyunwoo Kim)
- Fix POSIX CPU timers race between expiry and timer_settime(),
to prevent UAF (Thomas Gleixner)
* tag 'timers-urgent-2026-09-20' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
posix-cpu-timers: Prevent freeing a timer which is queued on the expiry list
exec: Cleanup POSIX timers right after de_thread()
signal: Prevent exec() race
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fix from Ingo Molnar:
- Avoid false positive migration warning for proxy donors
(Andrea Righi)
* tag 'sched-urgent-2026-09-20' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/core: Avoid false migration warning for proxy donors
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf events fixes from Ingo Molnar:
- Fix crash when probing CS CALL instructions (Jinke Han)
- Fix NULL pointer crash during module unload (Vinay Belgaumkar)
* tag 'perf-urgent-2026-09-20' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf: Fix null pointer access in is_include_guest_event()
x86/kprobes: Fix crash when probing CS CALL instructions
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull futex fix from Ingo Molnar:
- Also allocate a default private futex hash on vfork() as well, to
avoid races with (private) futex waiters (Peter Zijlstra)
* tag 'locking-urgent-2026-09-20' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
futex: Also allocate private hash on vfork()
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Kijo analyzed another race in the POSIX CPU timer code:
Commit bf635681c906 converted cpu_timer::firing from a tristate value to a
boolean. This lost the distinction between "not owned by the firing list"
and "still owned, but delivery was canceled". The resulting race is:
expiry handler timer_settime() timer_delete()
-------------- --------------- --------------
collect timer onto
private firing list
firing = true
observes firing = true
firing = false
return TIMER_RETRY
wait for handler
observes firing = false
finish deletion
unhash and free timer
resume list traversal
read freed elist.next
-> UAF
The firing bit is clearly the wrong indicator since that commit.
Check whether the timer is queued on the expiry list or not instead. If it
is queued clear the firing bit to prevent signal delivery as before and
return TIMER_RETRY so the caller unlocks the timer which allows the expiry
code to make progress and remove it from the list.
Fixes: bf635681c906 ("posix-cpu-timers: Cleanup the firing logic")
Reported-by: Kijo Park <red993688@gmail.com>
Debugged-by: Kijo Park <red993688@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Kijo Park <red993688@gmail.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Cc: stable@vger.kernel.org
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Proxy execution can move a blocked donor's scheduling context to the
lock owner's CPU even when the donor is migration-disabled. The donor
does not execute there, and its original execution CPU remains recorded
in wake_cpu.
set_task_cpu() warns unconditionally for migration-disabled tasks, so a
subsequent proxy migration or the wakeup path returning the donor home
triggers a false positive: moving a blocked scheduling context does not
violate the migration-disabled execution context.
For example, creating a mutex owner on CPU1 and a migration-disabled
waiter on CPU0 can trigger the following warning:
proxy_migrate_repro: donor blocking on CPU0 with migration disabled
proxy_migrate_repro: donor moved from CPU0 to CPU1
WARNING: kernel/sched/core.c:3389 at set_task_cpu+0x1d3/0x280
...
Call Trace:
try_to_wake_up+0x43f/0x780
__mutex_unlock_slowpath+0x330/0x540
owner_fn+0x9f/0xc0 [proxy_migrate_repro]
...
proxy_migrate_repro: donor woke on CPU0, task_cpu=0
proxy_migrate_repro: completed
Exclude blocked proxy donors from the warning. The proxy wakeup path
restores an executable placement before clearing the blocked state.
Fixes: b049b81bdff6 ("sched: Handle blocked-waiter migration (and return migration)")
Signed-off-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: John Stultz <jstultz@google.com>
Link: https://patch.msgid.link/20260915184101.2621252-1-arighi@nvidia.com
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A typical module unload occurring event when there is an active perf
connection leads to freeing of the pmu pointer. The call log is something
like:
..
__pmu_detach_event
pmu_detach_event
pmu_detach_events
perf_pmu_unregister
..
__pmu_detach_event() sets event->pmu to null. When the perf connection
finally is closed, the following stack trace is observed:
Oops: general protection fault, kernel NULL pointer dereference
...
RIP: 0010:_free_event+0x3e/0x370
...
Call Trace:
...
perf_event_release_kernel+0x260/0x2d0
perf_release+0x12/0x20
A call to mediated_pmu_unaccount_event() inside _free_event() is the root
cause of this crash. Adding a check inside is_include_guest_event() ensures
we don't accidentally access a null pmu ptr. In addition to this, we will
now call mediated_pmu_unaccount_event() before clearing the pmu ptr so that
nr_include_guest_events counts are maintained correctly.
Fixes: eff95e170275 ("perf: Add APIs to create/release mediated guest vPMUs")
Assisted-by: Claude:Claude-Sonnet-5
Signed-off-by: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Link: https://patch.msgid.link/20260904181625.1394082-1-vinay.belgaumkar@intel.com
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git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux
Pull dma-mapping fixes from Marek Szyprowski:
"A few fixes for the DMA-mapping code:
- resolved regression in accessing encrypted memory by IOMMU-backed
devices (Aneesh Kumar K.V)
- improved failure handling and removed rare bug in swiotlb/highmem
(Donggeun Yoo)"
* tag 'dma-mapping-7.3-2026-09-17' of git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux:
x86/mm: Don't force unencrypted DMA for IOMMU-backed devices
dma-mapping: don't trace the DMA address when the allocation fails
swiotlb: use the adjusted address for the highmem page lookup
dma-coherent: report a failed reserved memory assignment
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Hyunwoo debugged the following KASAN UAF splat:
BUG: KASAN: slab-use-after-free in __send_signal_locked+0xb27/0xba0
Write of size 8 at addr ffff888007ed80c8 by task poc/79
...
Call Trace:
__send_signal_locked+0xb27/0xba0
do_send_sig_info+0xa7/0x160
do_send_specific+0x76/0xa0
__x64_sys_tgkill+0x193/0x270
...
Allocated by task 80:
do_timer_create+0x1a4/0x1030
__x64_sys_timer_create+0x145/0x190
...
Freed by task 12:
kmem_cache_free_bulk+0x1f8/0x4a0
kvfree_rcu_bulk+0x14f/0x1c0
kfree_rcu_work+0x128/0x1a0
...
Last potentially related work creation:
kvfree_call_rcu+0x39/0x390
__flush_itimer_signals+0x211/0x320
flush_itimer_signals+0x47/0x90
begin_new_exec+0xa6b/0x28c0
It turned out that this happens with a non-leader exec() as Hyunwoo
explained:
de_thread() calls exchange_tids() before release_task(leader), so the
struct pid held by a SIGEV_THREAD_ID timer created against the leader's tid
now points to the thread which called execve(). pid_task() returns that
thread and lock_task_sighand() on it succeeds.
If the timer signal is blocked, its sigqueue stays queued on the leader's
task::pending. The next expiry of that timer can then run while
release_task() flushes the queue.
posixtimer_send_sigqueue() checks whether the sigqueue is already queued
with a plain list_empty(), which only reads list_head::next.
list_del_init() is not atomic and INIT_LIST_HEAD() stores list_head::next
before list_head::prev, so the check can pass in between. list_add_tail()
queues the entry on the task::pending of the live thread, and the
list_head::prev store from the flush then overwrites the list_head::prev
link that list_add_tail() has just set.
__flush_itimer_signals() does not undo that either. With list_head::prev
pointing at the entry itself, its list_del_init() only stores the same
values again, so the entry is not removed from the list. It is still there
after the last reference is dropped and the timer is freed by RCU, and the
list_add_tail() of a later tgkill() follows that list_head::prev into the
freed timer.
This problem surfaced with the recent commit which moved the sigqueue flush
out of the sighand lock held region.
Hyonwoo proposed to fix this by using list_del_init_careful(), but that
just papers over the problem. After some disucssions and various attempts
to solve it, Eric pointed out that there is no reason to flush
task::pending late in release_task() and it should be done in
exit_signals() already.
As nothing can collect and deliver signals which are queued in a dying
task's pending queue, there is no reason to delay it further.
But it has to be ensured that no signals can be queued into it after that
point. exit_signals() sets PF_EXITING in task::flags, which can be used as
an indicator for this.
Cure it by:
- Preventing signal queueing for task private signals (PIDTYPE_PID) when
the task has PF_EXITING set in __send_signal_locked() and in
posixtimer_send_sigqueue().
- Protecting the unlocked setting of PF_EXITING in exit_signals() for the
task group empty and the group exit case with sighand lock
- Flushing task::pending signals right there.
Optimize that by moving the whole pending list to an on-stack list head
under sighand lock and free the signals without the lock held.
There has been quite some discussion about the lockless flush and the
non-leader exec case on weakly ordered systems. The problem is that a third
party which tries to send a posix timer signal relies on the PID lookup to
find the target task and that lookup might result in the new leader when
the signal was originaly directed to the old leader. In case that the
signal was queued on the old leader then the lockless flush raised a
concern over the following situation:
old_leader new_leader third party
A: flush_list() // list_del_init() stores to sigqueue
LOCK (tasklist)
old_leader->exit_state = EXIT_ZOMBIE;
B: UNLOCK (tasklist)
C: LOCK (tasklist)
if (old_leader->exit_state)
transfer_tids()
D: store PID
posix_timer_send_sigqueue()
// Observes #D so t = new_leader
E: t = get_target()
F: LOCK (sighand)
G: if (list_empty(sigqueue))
list_add(sigqueue)
The concern was that the third party might observe #D but not observe #A
and therefore would proceed to #G while the list_del() stores (#A) in
flush_list() are not visible yet, which could result in list corruption.
That would be possible if looking at it solely from a RELEASE+ACQUIRE
ordering point of view, but B-C is a UNLOCK+LOCK hand-over, which is not
the same as RELEASE+ACQUIRE:
RELEASE+ACQUIRE: RCpc, only the CPUs involved agree on the ordering
UNLOCK+LOCK: RCtso, the hand-over is store-ordering
As B-C is UNLOCK+LOCK, which is RCtso and that does impose store order,
A stores must happen before the D store.
Combine with E-F, which has a data dependency from the LOAD to the LOCK and
thereby constraints later LOADs, those sigqueue loads in G that come after
F must in fact observe the A stores.
Fixes: fb3bbcfe344e ("exit: change the release_task() paths to call flush_sigqueue() lockless")
Reported-by: Hyunwoo Kim <imv4bel@gmail.com>
Debugged-by: Hyunwoo Kim <imv4bel@gmail.com>
Suggested-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Kijo Park <red993688@gmail.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260911090541.572536604@kernel.org
Closes: https://patch.msgid.link/aok1rdkBgZsynHZB@v4bel
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As Jann demonstrated, it is entirely feasible to access the mm through vfork().
Therefore we need to allocate a private hash on vfork() as well as any other
CLONE_VM user.
Specifically, it must be avoided to have (private) futex waiters before
allocating the private hash.
Fixes: ee9dce44362b ("futex: Drop CLONE_THREAD requirement for private default hash alloc")
Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260911090447.GT788244@noisy.programming.kicks-ass.net
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git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext
Pull sched_ext fixes from Tejun Heo:
- An error raised by a BPF program before the scheduler finished
enabling was consumed by the disable path's pre-enable shortcut,
leaving a running scheduler that couldn't be disabled and was later
freed while in use.
- Two compat kfuncs dereferenced a NULL scheduler when handed an exited
or idle task, oopsing the kernel.
- Keep-running decisions in the dispatch path used the root scheduler's
flags for tasks belonging to a sub-scheduler, causing warnings and
stalls.
- Schedulers with their own CPU ID mapping had no way to learn which
IDs are online. Add a kernel-maintained online mask to plug the hole.
- Cgroup idle state: the initial cpu.idle state wasn't passed on cgroup
init and same-value rewrites delivered spurious callbacks.
- Example scheduler fixes for a reenqueue loop on attach, placements on
CPUs without effective grants, stalled partition work and stale idle
tracking.
* tag 'sched_ext-for-7.3-rc3-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext:
sched_ext: Maintain an online cid mask in the scheduler arena
sched_ext: scx_qmap: Restore unused idle claims from ops.dispatch()
sched_ext: Close the pre-enable ops error claim window
sched_ext: scx_qmap: Fix pending partition work handoff
sched_ext: scx_qmap: Place only on cids whose caps are in effect
sched_ext: scx_qmap: Do not add IMMED to rescue inserts
sched_ext: Use @prev's scheduler for the keep decisions in dispatch_one()
sched_ext: Rename sch to root_sch in dispatch_one()
sched_ext: Fix NULL sched deref in kfunc sub-sched error paths
sched_ext: Don't deliver duplicate ops.cgroup_set_idle() for same value
sched_ext: Pass the initial cpu.idle state in scx_cgroup_init_args
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git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup fix from Tejun Heo:
- The task iterator could pick up a dying task whose refcount had
already dropped to zero and resurrect it, leading to a use-after-free
when reading cgroup.procs. Skip such tasks.
* tag 'cgroup-for-7.3-rc3-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup: Avoid iteration of dying tasks with zero refcount
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Schedulers on the default cid mapping treat [0, nr_online_cids) as the
online set and restart on hotplug. Schedulers that install their own mapping
with scx_bpf_cid_override() have no way to learn which cids are online: the
count no longer identifies members and the CPU-form cpumask is unusable from
cid programs. This is an obvious hole in the cid API.
Add scx_bpf_online_cmask(), a kernel-maintained cmask in the scheduler's
arena, allocated alongside the per-CPU scratch masks and populated after the
cid mapping is finalized and before ops.init(), for child schedulers too.
The pointer stays valid through ops.exit() with no reference to take. It is
the arena offset as a void pointer, the same form struct_ops arena arguments
arrive in. The verifier types the void return as a scalar for the program's
arena cast.
The mask follows the SCX hotplug notifications: seeded from cpu_active_mask
and updated before ops.cid_online/offline() runs, so it lags cpu_online_mask
only inside a hotplug transition. Updates walk the scheduler list under the
lock that also serializes unlinking. Reads are live, not atomic snapshots.
Root initialization excludes hotplug.
v2: Reworded the getter kerneldoc (Andrea Righi).
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Andrea Righi <arighi@nvidia.com>
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scx_qmap tracks idle cids itself. pick_direct_dispatch_cid() claims a cid by
clearing its bit and the task is inserted into that cid's local DSQ, which
kicks the CPU. When the task does not arrive, for example because the insert
fell back to the global DSQ after an affinity change, the CPU wakes, finds
nothing and picks idle again. That is not an idle transition, so
ops.update_idle() is not called and the cid stays marked busy until an
unrelated task runs on it.
Restore the claim from ops.dispatch(). The kick guarantees a dispatch on the
kicked CPU, and when it finds nothing to run with a NULL @prev, the CPU is
going back to idle. Document the pattern in ops.update_idle(), which reports
only actual transitions.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Andrea Righi <arighi@nvidia.com>
Cc: Andrea Righi <arighi@nvidia.com>
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Return MAX_JIFFY_OFFSET for all the values truncated when val (u64) is
passed to msecs_to_jiffies (u32). This aligns with how very large
millisecond values get translated into MAX_JIFFY_OFFSET.
Fixes: b96b5c6708ea ("sysctl: Replace do_proc_do{int,ulong,uint}vec with do_proc_vec")
Suggested-by: Kuniyuki Iwashima <kuniyu@google.com>
Signed-off-by: Joel Granados <joel.granados@kernel.org>
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Add the range check back to do_proc_ulong_conv_ms_jiffies that commit
b96b5c6708ea ("sysctl: Replace do_proc_do{int,ulong,uint}vec with
do_proc_vec") incorrectly removed. Append "_minmax" to the end of
do_proc_ulong_conv_ms_jiffies so it is clear that there should be a
range check.
Fixes: b96b5c6708ea ("sysctl: Replace do_proc_do{int,ulong,uint}vec with do_proc_vec")
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Signed-off-by: Joel Granados <joel.granados@kernel.org>
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Add the range check to do_proc_int_conv_ms_jiffies_minmax that commit
d174174c6776 ("sysctl: replace SYSCTL_INT_CONV_CUSTOM macro with
functions") incorrectly removed.
Fixes: d174174c6776 ("sysctl: replace SYSCTL_INT_CONV_CUSTOM macro with functions")
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Signed-off-by: Joel Granados <joel.granados@kernel.org>
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The commit 260fbcb92bbea ("cgroup: Move dying_tasks cleanup from
cgroup_task_release() to cgroup_task_free()") extended the lifetime of
tasks on the dying_tasks list.
The iterators have provision to go through dying_tasks because of
dying threadgroup leaders or explicit CSS_TASK_ITER_WITH_DEAD, however,
it was expected that such tasks can obtain a new reference (that is
possible before cgroup_task_release()/put_task_struct_rcu_user()).
The tasks after cgroup_task_release() and before cgroup_task_free()
are subject to race when they may or may not have ->usage count > 0.
The race window is between css_task_iter_next() invocations
when css_set_lock is released and we may arrive at a new ->task_pos.
The iterator should not attempt to resurrect tasks whose ->usage count
dropped to zero. (When that happens, __put_task_struct_rcu_cb() is
already imminent and the returned task_struct would could be used
after free.)
As for the fix, we cannot simply check the signal->live count of a task
on the dying list because that won't distinguish regular zombies waiting
to be reaped from RCU remnant tasks that are going to be free'd.
Therefore add an extra check to rule out ->usage==0 tasks from any
iteration.
The repeat: loop in css_task_iter_advance() doesn't consider ->usage
count, so add a new loop to css_task_iter_next() to skip de-used tasks
on the dying_list.
Rough illustration of the possible race
R (reader of cgroup.procs) T (thread) L (group leader)
--------------------------------- -------------------------------- --------------------------------
L exits, signal->live > 0
cgroup_task_dead(L)
css_set_skip_task_iters() // skips only cset->tasks
list_add_tail(&L->cg_list, &cset->dying_tasks)
css_task_iter_next()
take css_set_lock
css_task_iter_advance()
leader && signal->live != 0
=> it->task_pos = &L->cg_list
release css_set_lock
T exits
--signal->live == 0
cgroup_task_dead(T) // css_set_lock
release_task(T)
cgroup_task_release(T)
release_task(L) // zap_leader
cgroup_task_release(L)
put_task_struct_rcu_user(L)
...RCU...
put_task_struct(L)
L->usage = 0
/* L still on dying_tasks */
...RCU...
__put_task_struct(L)
css_task_iter_next() // another iteration
take css_set_lock
it->task_pos = &L->cg_list
get_task_struct(L)
=> addition on 0
drop css_set_lock
cgroup_task_free(L)
css_set_skip_task_iters() // dying skip comes too late
free_task(L)
cgroup_procs_show()
task_pid_vnr(L)
Fixes: 260fbcb92bbea ("cgroup: Move dying_tasks cleanup from cgroup_task_release() to cgroup_task_free()")
Cc: stable@vger.kernel.org # v6.19+
Link: https://lists.debian.org/debian-kernel/2026/08/msg00220.html
Reported-by: Noah Elias Feldt <N.Feldt@mittwald.de>
Reported-by: Salvatore Bonaccorso <carnil@debian.org>
Tested-by: Salvatore Bonaccorso <carnil@debian.org>
Signed-off-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing fixes from Steven Rostedt:
- Don't destroy user event fields when removal fails
User event fields are destroyed before the event is removed from
visibility. But that can fail leaving the still visible event with no
fields. Move the destroying of the fields to after the event is
successfully removed from visibility.
- Initialize function graph state is fork before calling
copy_exec_state()
For non-CLONE_VM forks, copy_exec_state() allocates a new
task_exec_state. If that allocation fails, ftrace_graph_exit_task()
will free the tasks ret_stack pointer. Since that pointer is still
using the parent's ret_stack, it mistakenly frees the parent's
pointer too.
Call ftrace_graph_init() on the task first which will NULL out the
new tasks's ret_stack and if the copy fails, it will not free
anything.
- Remove FGRAPH_MAX_INDEX
The macro FGRAPH_MAX_INDEX was added but never used. Remove it.
- Save ent_size in function graph printing of nested functions
The function graph tracer needs to look at the next event to see if
the next event is the return of the current function entry. If it is,
it prints a single line:
ktime_get();
Otherwise it prints it like a nested function:
tick_nohz_irq_exit() {
ktime_get();
kcpustat_irq_exit();
}
In order to look at the next event, it must save the current event so
that it has the information to print from it. It saves the event in
the iterator descriptor called "ent". What it doesn't save is the
ent_size of the event which is now used to know if the function graph
arguments are to be printed. The peek doesn't save the size so the
size used happens to be that of the size of the last event that was
seen.
Save the entry event size in the iterator descriptor so that the
correct size is used.
- Fix several errors with freeing data in the histogram code
The histogram code had a lot of leaked or or incorrect accounting
when failures happen. Correct them.
- Fix histogram regression of .percent and .graph modifiers
Up until 6.3 histogram values could have "percent" or "graph"
modifiers that changed how they were printed. But a change that added
restricting histograms values from being strings, stack traces and
other modifiers inadvertently prevented them from using the percent
and graph modifiers, which were legal use cases for values.
Put back the percent and graph modifiers.
- Fix various typos in the comments
- Set the trace_clock before initializing a histogram with clock
argument
The histogram API allows the user to specific which trace clock to
use via a "clock=" string. The histogram is set up first before the
clock is checked. If the passed in clock is not valid, it exits
without fully fixing up the histogram leaving it on the list and a
use-after-free can trigger.
Update the clock argument first and if it fails then exit gracefully
before the histogram trigger is placed on any lists.
- Restore :mod: trailer after parsing in ftrace_set_clr_event
The function ftrace_set_clr_event() modifies the parse string and
needs to put it back to what was passed in. It searches for ":mod:"
via a strsep() but fails to put back the first ':' in the string.
Add back the ':' in the passed in string.
- Take trace_array reference when opening a tracer options file
The options files are dynamically created and some tracers add their
own options. When a tracer adds their own list of options, the
trace_array holding them has an array to hold the list of options for
each tracer. This array increases in size via a krealloc(), and the
new entry gets a newly allocated array to hold the options of the new
tracer being added.
The element in each entry of the tracer's option array holds a
pointer back to the trace_array, a pointer to the tracer it is
associated to, a pointer to the flags of the option.
The issue is that these arrays are freed when the trace_array is
freed when its instance it represents is removed from the instances
directory. There's a race that an open of one of these options files
can happen when the instance is being removed.
Add a new helper function to be called by the open function of the
options file to iterate all existing trace_arrays under a lock and
find the one that has the given option element in one of it's tracer
arrays. If found, then update the associated trace_array's reference
counter to keep it from being freed. If not found, have the open call
return -ENODEV.
- Disable interrupts when acquiring the lock in rb_wake_up_waiters()
The function rb_wake_up_waiters() assumes it will be called in
interrupt context and does not disable irqs when taking
cpu_buffer->reader_lock, which can be called in hard interrupt
context. The issue is in PREEMPT_RT, this function is called in
thread context leaving this lock open to a deadlock.
Take the lock with interrupts disabled.
- Use rcu_assign_pointer() for tmp_ops filter hash
The tmp_ops used in update_ftrace_direct_mod() assigns its
filter_hash field directly, but that field is annotated as __rcu and
sparse complains. Assign it with rcu_assign_pointer()
- Fix use-after-free in enable_trigger_private_data_free()
The trace_event_call is accessed through the event_trigger_data's
trace_event_file pointer to put the trace_event_call on freeing. The
issue is that the trace_event_file data may have been freed already
causing a use-after-free. Add a field to the event_trigger_data that
points directly to the trace_event_call so that it can decrement its
reference directly without needing to go through the
trace_event_file.
- Fix accounting of buffer data remote headers
trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount
the number of pages is needed for the asked for size as it doesn't
take into account the meta data on each page. Add a helper function
to do the calculation properly and use that in these functions.
- Catch nr_page_va overflow in ring_buffer_desc sizing
The number of pages per remote ring buffer is capped by
ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to
overflow that field would silently allocate a descriptor smaller than
what was asked for.
- Do not resize the subbuf order if any per_cpu buffer is disabled
The mmapping of ring buffers disables resizing the subbuffers, but it
is done per-cpu whereas the subbuf size change is done for all the
per_cpu buffers under the buffer->mutex. It could change the size of
some while the mapping is happening on others. Have the resize of the
subbuf order check all the per_cpu buffers under the lock to see if
any of them is disabled before starting and causing an inconsistency
between buffers that are being mapped.
* tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits)
ring-buffer: Check resize_disabled before publishing the new subbuf order
tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing
tracing/remotes: Account for ring buffer page header in size calculation
tracing: Don't dereference trace_event_file in deferred trigger free
ftrace: Use rcu_assign_pointer() for tmp_ops filter hash
ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters()
tracing: Take trace_array reference when opening a tracer options file
tracing: Fix ring_buffer_read_page_size() kernel-doc
tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event()
tracing: Fix memory corruption from a "STACKTRACE" histogram key
tracing: Fix memory corruption from the histogram stacktrace modifier
tracing: Undo the registration when enabling the histogram trigger fails
tracing: Take the reference before publishing the named histogram trigger
tracing: Set the trace clock before registering the histogram trigger
tracing: Fix typo "preceeded" in comment
tracing: Fix typo "availabe" in comment
tracing: Let histogram values keep the percent and graph modifiers
tracing: Keep the entry count when the histogram stats allocation fails
tracing: Free histogram the field rejected for a bad modifier
tracing: Free histogram the var ref when its initialization fails
...
|
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ring_buffer_subbuf_order_set() stores the new order and only then walks
the CPUs, returning -EBUSY if any of them has resizing disabled. A user
mapped buffer has resizing disabled, and __rb_map_vma() reads
buffer->subbuf_order without buffer->mutex, so an mmap of an already
mapped CPU racing the failing order change sizes the mapping with the
new order and inserts pages past the sub-buffer into the VMA.
Check the CPUs before storing the new order.
Cc: stable@vger.kernel.org
Fixes: 117c39200d9d ("ring-buffer: Introducing ring-buffer mapping functions")
Link: https://patch.msgid.link/20260912103938.1127021-1-devnexen@gmail.com
Signed-off-by: David Carlier <devnexen@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
|
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The number of pages per remote ring buffer is capped by
ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to
overflow that field would silently allocate a descriptor smaller than
what was asked for.
Return SIZE_MAX from trace_buffer_desc_size() on nr_page_va overflow.
Link: https://patch.msgid.link/20260911193937.602202-3-vdonnefort@google.com
Fixes: 2e67fabd8b77 ("ring-buffer: Introduce ring-buffer remotes")
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
|
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trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount the
required pages because every ring buffer page contains a header
(BUF_PAGE_HDR_SIZE). Account for that header to ensure allocated remote
ring buffers aren't smaller than requested by the user.
The newly introduced helper __calc_nr_pages_ring_buffer_desc() can
return a value that overflows the descriptor nr_pages field (32 bits).
Link: https://patch.msgid.link/20260911193937.602202-2-vdonnefort@google.com
Fixes: 2e67fabd8b77 ("ring-buffer: Introduce ring-buffer remotes")
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
|
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer fixes from Ingo Molnar:
- Fix clockevents replacement race when a broadcast
device is replaced which may trigger a BUG() crash
(朱恺乾 - Zhu Kaiqian)
- Fix potential timerqueue ordering bug when rearming
a queued timer with nonzero slack (Andrea Parri)
* tag 'timers-urgent-2026-09-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
hrtimer: Use hard expiry when updating timers on the same base
tick/broadcast: Plug clockevents replacement race
|
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar:
- Fix EEVDF se->max_slice value on enqueueing (Vincent Guittot)
- Fix EEVDF augmented rb-trees re-balancing with multiple
fields (Vincent Guittot)
- In proxy scheduling, account cgroup CPU time to the execution
context, not the scheduling context (Hui Su)
- Likewise, call wq_worker_tick() for the execution context,
not the scheduling context (Hui Su)
* tag 'sched-urgent-2026-09-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/core: Call wq_worker_tick() for the execution context
sched: Account cgroup CPU time to the execution context
sched/eevdf: Fix rb augmented with multi fields
sched/eevdf: Fix augmented max_slice
|
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scx_alloc_and_add_sched() publishes ops->priv before
scx_root_enable_workfn() switches the state to SCX_ENABLING. An error
claimed via scx_bpf_error_bstr() from an associated BPF program in that
window is consumed by scx_disable_workfn(), which takes the pre-enable
shortcut in scx_root_disable(). The shortcut returns without any teardown
and restores SCX_DISABLED with an unconditional scx_set_enable_state() xchg
racing the enable workfn's own transition. The enable then completes with
the claim consumed: the scheduler stays up but can never be disabled again,
and bpf_scx_unreg() frees it while still in use, resulting in a
use-after-free. Both WARN_ON_ONCE()s fire back to back:
WARNING: kernel/sched/ext/ext.c:7522 at
scx_root_enable_workfn+0xeec/0x1be0, CPU#3: scx_enable_help/276
WARNING: kernel/sched/ext/ext.c:6398 at scx_root_disable+0xb50/0xdb8,
CPU#0: sched_ext_helpe/664
scx_root_enable_workfn() switches to SCX_ENABLING before the scheduler
allocation, so ops->priv is never visible while SCX_DISABLED. The allocation
failure path restores SCX_DISABLED.
Fixes: 105dcd005be2 ("sched_ext: Introduce scx_prog_sched()")
Cc: stable@vger.kernel.org
Signed-off-by: fangqiurong <fangqiurong@kylinos.cn>
Signed-off-by: Tejun Heo <tj@kernel.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf events fixes from Ingo Molnar
- Fix sched_cb_list corruption on PMU callbacks that
invoke list_del() during perf_event_overflow()
calls (Thomas Richter)
- Fix PEBS pt_regs->flags snapshot data that
regressed with the introduction of adaptive
PEBS v4 support (Dapeng Mi)
- Fix possible drain_pebs() re-entry bug when
intel_pmu_drain_pebs_buffer() is called from
process context (Dapeng Mi)
* tag 'perf-urgent-2026-09-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/x86/intel: Prevent drain_pebs() reentry
perf/x86/intel: Correct pt_regs->flags update for PEBS path
perf/core: Allow list_del during perf_event_overflow()
|
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The enable_event trigger defers trace_event_put_ref() to the
trigger free kthread, but the trace_event_file can already be freed
when the instance is removed.
Keep the trace_event_call directly in enable_trigger_data so the
deferred free does not access the freed trace_event_file.
Cc: stable@vger.kernel.org
Fixes: e091351b3881 ("tracing: Delay module ref count for "enable_event" trigger")
Reported-by: Alexander Gordeev <agordeev@linux.ibm.com>
Closes: https://lore.kernel.org/all/20260828134340.2501683A24-agordeev@linux.ibm.com/
Link: https://patch.msgid.link/20260911155650.354844-1-aliamemis@disroot.org
Signed-off-by: Ali Ahmet Memiş <aliamemis@disroot.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
|
|
tmp_ops.func_hash->filter_hash is annotated __rcu, but
update_ftrace_direct_mod() assigns hash to it directly. Sparse reports an
address-space mismatch.
Use rcu_assign_pointer() for the assignment.
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260911142512.19344-1-leon.hwang@linux.dev
Fixes: 50b35c9e50a8 ("ftrace: Use hash argument for tmp_ops in update_ftrace_direct_mod")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202609110704.Q3M5vCDV-lkp@intel.com/
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
|
|
rb_wake_up_waiters() is a irq_work callback which is initialized with
init_irq_work(). As such it will be invoked in thread context on
PREEMPT_RT. Invoking the callback in IRQ context on PREEMPT_RT is not an
option due its usage of wake_up_all(). Since this callback may run in
thread context, it needs to acquire ring_buffer_per_cpu::reader_lock with
disabling interrupts and may not assume that they are disabled.
Use raw_spinlock_irqsave() to acquire ring_buffer_per_cpu::reader_lock.
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260911102152.YEtwkBj9@linutronix.de
Fixes: 68282dd930ea3 ("ring-buffer: Fix resetting of shortest_full")
Reviewed-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
|
|
When a tracer option file is opened, it is passed a descriptor that points
to an element on the trace_array's topts array. This element has
information to find the trace array and other information. It uses this
element to take a reference of the trace_array so that the trace_array
does not get removed while this file is opened.
Unfortunately, there's a race condition where the element itself could be
freed by the removal of the instance the trace_array represents causing a
use-after-free as this element that is used to find the trace_array to
increment its reference counter is also freed when the instance is
removed.
To solve this, add a trace_array_tracer_options_get() helper function that
will take the address of the element that is passed to the open function
by the inode->i_private pointer and search all the trace_arrays under a
lock to find the one that the element's address is in the range of the
trace_arrays topts array elements. When a match happens, that trace_array's
reference would be increased.
Note, there's a race where if an admin was deleting and creating trace
instances at the same time and the memory of the old trace_array's array
matched the memory of the new trace_array that it could in theory open the
option from the wrong trace array. But we do not care because it would be
stupid to perform that kind of action. As long as the only thing that can
happen is that the option from the wrong trace array is used and doesn't
crash the kernel it will only make the user confused. But if they are
doing something stupid like this, they are already confused, so no harm
done.
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260910221209.62dad8d3@robin
Fixes: 7e2cfbd2d3c86 ("tracing: Have option files inc the trace array ref count")
Reported-by: sashiko-bot@kernel.org
Closes: https://lore.kernel.org/linux-trace-kernel/20260902121918.5a9e9d1b@gandalf.local.home/
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
|
|
ring_buffer_read_page_size() takes a parameter named rpage, but its
kernel-doc describes page. As a result, kernel-doc reports rpage as
undescribed and page as an excess parameter description.
Rename the documentation entry to match the function.
Link: https://patch.msgid.link/20260909062917.89482-1-kmehltretter@gmail.com
Fixes: dae8dda341d2 ("tracing: Fix subbuf resize races with trace_pipe_raw readers")
Assisted-by: LLM
Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com>
Reviewed-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
|
|
While ftrace_set_clr_event() modifies its input buffer during parsing,
before returning to the caller the buffer is supposed to be restored
to its original state.
This works correctly for the colon between the subsystem and event
but not the colon at the beginning of :mod:.
Restore the colon, so the :mod: trailer is not stripped after
ftrace_set_clr_event().
Cc: stable@vger.kernel.org
Fixes: 4c86bc531e60 ("tracing: Add :mod: command to enabled module events")
Link: https://patch.msgid.link/20260908-tracing-cli-event-filter-v2-1-05396a3fb663@linutronix.de
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
|
|
"cpu", "CPU", "stacktrace" and "STACKTRACE" are generic fields, defined
with an offset and a size of zero so that the filter code can match them
by name. parse_field() maps them onto their common_* equivalents for
backward compatibility, but unlike the common_* names it hands the
placeholder back to the caller instead of NULL.
create_hist_field() takes a non-NULL field as a promise that the record
carries a stacktrace and picks HIST_FIELD_FN_STACK, so the __data_loc
word is read from offset 0, that is from common_type, and its low 16
bits are followed as an offset into the record. What is found there
becomes the length of an unbounded memcpy. Pick an event whose id is
small enough that the offset stays inside its own record and the length
is a kernel text address:
# cd /sys/kernel/tracing
# echo 'hist:keys=STACKTRACE' > events/ftrace/print/trigger
# echo hello > trace_marker
Oops: general protection fault, probably for non-canonical address
RIP: 0010:rb_next+0x23/0x60
</IRQ>
RIP: 0010:memcpy+0xc/0x30
event_hist_trigger+0x2e7/0x12c0
Kernel panic - not syncing: Fatal exception in interrupt
Leave the field NULL, which is what the comment above the branch says
the code does and what common_stacktrace already does. FILTER_CPU and
FILTER_COMM are left alone, their create_hist_field() branches never
look at the field.
Cc: stable@vger.kernel.org
Fixes: 4b512860bdbd ("tracing: Rename stacktrace field to common_stacktrace")
Link: https://patch.msgid.link/20260907155045.692664-3-donggeunyoo.kernel@gmail.com
Signed-off-by: Donggeun Yoo <donggeunyoo.kernel@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
|
|
parse_field() sets HIST_FIELD_FL_STACKTRACE from the ".stacktrace"
modifier before it looks the field name up, and nothing afterwards
checks that the name resolved to a field which holds a stacktrace.
create_hist_field() picks HIST_FIELD_FN_STACK on the strength of the
field pointer alone, which reads a __data_loc word from the record and
follows its low 16 bits as an offset into the same record.
event_hist_trigger() takes the first word there as an entry count and
copies that many longs into a 31 entry array:
n_entries = *stack;
memcpy(entries, ++stack, n_entries * sizeof(unsigned long));
Neither end of that copy is bounded, and the count is whatever the event
holds at the offset, so any field will do:
# cd /sys/kernel/tracing/events/sched/sched_process_fork
# echo 'hist:keys=parent_pid.stacktrace' > trigger
# (true)
BUG: kernel NULL pointer dereference, address: 0000000000000008
RIP: 0010:rb_insert_color+0x18/0x130
timerqueue_linked_add+0x7e/0xd0
enqueue_hrtimer+0x39/0xb0
__hrtimer_run_queues+0x10f/0x1f0
</IRQ>
RIP: 0010:memcpy+0xc/0x30
event_hist_trigger+0x165/0x690
The timer interrupt landed on the rbtree the copy had already run over.
No debug options are needed for this; KASAN reports the same write as an
out-of-bounds read of 13835058055416381440 bytes.
Documentation/trace/histogram.rst already states the rule, "must be a
long[] type", so enforce it once the name has been resolved. Names which
resolve to no field at all, "hitcount.stacktrace" and the common_*
pseudo-fields, are refused for the same reason: they hold no stacktrace
to read.
Cc: stable@vger.kernel.org
Fixes: cc5fc8bfc961 ("tracing/histogram: Add stacktrace type")
Link: https://patch.msgid.link/20260907155045.692664-2-donggeunyoo.kernel@gmail.com
Signed-off-by: Donggeun Yoo <donggeunyoo.kernel@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
|
|
Commit 6f86bdeab633 ("tracing: Fix bad hist from corrupting named_triggers
list") described how a trigger that is registered but not on file->triggers
ends up freed while still on the global named_triggers list, and moved the
registration down so that hist_trigger_enable() follows it immediately. One
path still gets there. hist_trigger_enable() adds the trigger and takes it
straight back out when the event cannot be enabled:
list_add_tail_rcu(&data->list, &file->triggers);
update_cond_flag(file);
if (trace_event_trigger_enable_disable(file, 1) < 0) {
list_del_rcu(&data->list);
update_cond_flag(file);
ret--;
}
so the list walk in hist_unregister_trigger() matches nothing, test stays
NULL, and the ->free() that would call del_named_trigger() is skipped.
out_unreg falls through to out_free, which frees the trigger anyway:
BUG: KASAN: slab-use-after-free in find_named_trigger+0xac/0xc0
Read of size 8 at addr ffff8880091d3160 by task init/1
find_named_trigger+0xac/0xc0
hist_register_trigger+0xc1/0xa00
event_hist_trigger_parse+0x3146/0x6af0
event_trigger_write+0xce/0x160
Freed by task 69:
kfree+0x154/0x420
trigger_kthread_fn+0xfd/0x160
Leave the trigger where hist_unregister_trigger() can find it and let that
undo the registration, which is the only code that knows all of what
cmd_ops->init() took: the named list entry, the hist_pad reference, the
reference on the trigger a named histogram is shared with, and the copied
cmd_ops. It also pairs the failed trace_event_trigger_enable_disable(),
whose sm_ref and buffered event reference are otherwise left behind.
Since ->free() releases trigger_data and, for a trigger that does not share
its histogram, hist_data with it, out_unreg can no longer fall through to
out_free. For a trigger that does share, hist_register_trigger() has
already destroyed the caller's hist_data, so the fall-through was reading
freed memory there as well.
Move the enable_timestamps check in hist_unregister_trigger() above the
->free() call for the same reason: hist_data does not outlive it once the
trigger being removed is the one that owns it.
Cc: stable@vger.kernel.org
Fixes: 067fe038e70f ("tracing: Add variable reference handling to hist triggers")
Reported-by: Sashiko AI <sashiko-bot@kernel.org>
Closes: https://lore.kernel.org/linux-trace-kernel/20260907092944.3950E1F00A3D@smtp.kernel.org/
Link: https://patch.msgid.link/20260907124420.607097-3-donggeunyoo.kernel@gmail.com
Signed-off-by: Donggeun Yoo <donggeunyoo.kernel@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
|
|
event_hist_trigger_named_init() puts the trigger on the global
named_triggers list and only then takes the reference on the trigger it
shares its histogram with:
data->ref++;
save_named_trigger(data->named_data->name, data);
ret = event_hist_trigger_init(data->named_data);
if (ret < 0) {
kfree(data->cmd_ops);
data->cmd_ops = &trigger_hist_cmd;
}
return ret;
event_hist_trigger_init() fails when alloc_hist_pad() cannot allocate, and
nothing takes the trigger back off the list on the way out.
event_hist_trigger_parse() frees it, and the next lookup by name reads the
freed object:
BUG: KASAN: slab-use-after-free in find_named_trigger+0xac/0xc0
Read of size 8 at addr ffff888009346860 by task init/1
find_named_trigger+0xac/0xc0
hist_register_trigger+0xc1/0xa00
event_hist_trigger_parse+0x3146/0x6af0
event_trigger_write+0xce/0x160
Freed by task 67:
kfree+0x154/0x420
trigger_kthread_fn+0xfd/0x160
Do the reference first and publish once it has succeeded, so that nothing
which can fail runs after the trigger becomes findable.
Cc: stable@vger.kernel.org
Fixes: 7ab0fc61ce73 ("tracing: Move histogram trigger variables from stack to per CPU structure")
Reported-by: Sashiko AI <sashiko-bot@kernel.org>
Closes: https://lore.kernel.org/linux-trace-kernel/20260907092944.3950E1F00A3D@smtp.kernel.org/
Link: https://patch.msgid.link/20260907124420.607097-2-donggeunyoo.kernel@gmail.com
Signed-off-by: Donggeun Yoo <donggeunyoo.kernel@gmail.com>
Acked-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
|
|
hist_register_trigger() puts the trigger on the global named_triggers
list in cmd_ops->init(), and only then sets the trace clock:
if (data->cmd_ops->init) {
ret = data->cmd_ops->init(data);
if (ret < 0)
goto out;
}
if (hist_data->enable_timestamps) {
ret = tracing_set_clock(file->tr, hist_data->attrs->clock);
if (ret) {
hist_err(tr, HIST_ERR_SET_CLOCK_FAIL, errpos(clock));
goto out;
}
The clock string is not checked anywhere before that call, so a named
trigger using common_timestamp with an unknown clock fails after it has
already become findable. event_hist_trigger_parse() then frees it
without taking it off the list, and the next lookup by name reads the
freed object:
~# cd /sys/kernel/tracing/events/sched/sched_switch
~# echo 'hist:name=foo:keys=common_pid:ts=common_timestamp:clock=bogus' > trigger
bash: echo: write error: Invalid argument
~# echo 'hist:name=foo:keys=common_pid' > trigger
BUG: KASAN: slab-use-after-free in find_named_trigger+0xac/0xc0
Read of size 8 at addr ffff88800915d760 by task init/1
find_named_trigger+0xac/0xc0
hist_register_trigger+0xc1/0x900
event_hist_trigger_parse+0x3146/0x6af0
event_trigger_write+0xce/0x160
Freed by task 63:
kfree+0x154/0x420
trigger_kthread_fn+0xfd/0x160
Set the clock before the trigger is registered, so that nothing which
can fail runs after it is published, the way commit 6f86bdeab633
("tracing: Fix bad hist from corrupting named_triggers list") moved the
registration below the rest of the setup.
tracing_set_filter_buffering() is reference counted, so the init failure
path has to drop the reference that the clock block now takes first.
Cc: stable@vger.kernel.org
Fixes: a4072fe85ba3 ("tracing: Add a clock attribute for hist triggers")
Link: https://patch.msgid.link/20260907091415.554535-1-donggeunyoo.kernel@gmail.com
Signed-off-by: Donggeun Yoo <donggeunyoo.kernel@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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Correct "availabe" to "available", reported by scripts/checkpatch.pl using
the misspelling list in scripts/spelling.txt. Only touches comments, no
code changes.
Link: https://patch.msgid.link/20260907062608.13924-1-hemanth.selam@gmail.com
Assisted-by: Cursor:claude-opus-5
Signed-off-by: Hemanth Selam <hemanth.selam@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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The .percent and .graph modifiers exist only for histogram values, but a
value carrying either of them has been rejected since v6.3. The example
in Documentation/trace/histogram.rst,
# echo 'hist:keys=prev_comm:vals=hitcount.percent:nohitcount' > \
events/sched/sched_switch/trigger
returns -EINVAL.
parse_field() sets the two flags only when the field is neither a key nor
a variable, that is, only on a value:
} else if (strncmp(modifier, "percent", 7) == 0) {
if (*flags & (HIST_FIELD_FL_VAR | HIST_FIELD_FL_KEY))
goto error;
*flags |= HIST_FIELD_FL_PERCENT;
__create_val_field() then rejects a value for carrying them, so no field
can reach hist_trigger_print_val(), where both are implemented.
commit e0213434fe3e ("tracing: Do not let histogram values have some
modifiers") added the check after a value with .buckets oopsed in
hist_field_name(). That happens because .buckets and .log2 make
create_hist_field() build a nested field in operands[0] which
hist_field_name() then walks into. The percent and graph flags do not
create an operand and are not read by hist_field_name(); they are only
used when printing a value.
Stop rejecting the two flags on a value. The check for variables is left
alone, where they are unreachable anyway because parse_field() rejects a
variable carrying them first.
With the two flags removed, the trigger above installs and prints as
documented:
{ prev_comm: rcu_preempt } hitcount (%): 0.00
{ prev_comm: init } hitcount (%): 99.98
Totals:
Hits: 237896
Cc: stable@vger.kernel.org
Fixes: e0213434fe3e ("tracing: Do not let histogram values have some modifiers")
Link: https://patch.msgid.link/20260907052113.430818-1-donggeunyoo.kernel@gmail.com
Signed-off-by: Donggeun Yoo <donggeunyoo.kernel@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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print_entries() uses n_entries both as the number of sort entries and as
its own return value, so the -ENOMEM it stores when the stats allocation
fails overwrites the count that the cleanup still needs:
n_entries = tracing_map_sort_entries(map, ...);
if (n_entries < 0)
return n_entries;
...
if (!stats) {
n_entries = -ENOMEM;
goto out;
}
...
out:
tracing_map_destroy_sort_entries(sort_entries, n_entries);
tracing_map_destroy_sort_entries() takes an unsigned int and loops up to
it, so -ENOMEM arrives as 4294967284. It walks an array of at most
map->max_elts pointers and calls destroy_sort_entry(), which dereferences
and frees, on whatever lies past the end.
Reading the hist file of a trigger with a .percent value, with that
allocation forced to fail:
BUG: KASAN: vmalloc-out-of-bounds in tracing_map_destroy_sort_entries+0xa0/0xb0
Read of size 8 at addr ffffc90000045000 by task init/1
tracing_map_destroy_sort_entries+0xa0/0xb0
hist_show+0x6f7/0x1df0
seq_read_iter+0x2b8/0x1190
vfs_read+0x176/0xa40
The buggy address belongs to a 4-page vmalloc region starting at
ffffc90000041000 allocated at tracing_map_sort_entries+0x5c/0xd50
A few pages further the fault is fatal. The registers at the oops confirm
the bound: the loop's end pointer less the array start, over the pointer
size, is 4294967284.
Return the error in a separate variable and leave n_entries holding the
count, the way tracing_map_sort_entries() does on its own error path.
The stats block is only entered for a value carrying .percent or .graph,
which __create_val_field() has rejected since v6.3, so this cannot be
reached in mainline as it stands. It becomes reachable again with
"tracing: hist: let values keep the percent and graph modifiers", so it
should be applied first.
Cc: stable@vger.kernel.org
Fixes: abaa5258ce5e ("tracing: Add .percent suffix option to histogram values")
Link: https://patch.msgid.link/20260907060323.480728-1-donggeunyoo.kernel@gmail.com
Reported-by: sashiko-bot@kernel.org
Closes: https://lore.kernel.org/all/20260907053113.1CED91F00A3A@smtp.kernel.org/
Signed-off-by: Donggeun Yoo <donggeunyoo.kernel@gmail.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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Writing a hist trigger whose value or variable carries a modifier that is
not allowed there leaks the fields that were built for it.
__create_val_field() takes the field from parse_expr() and stores it in
hist_data->fields[] only after the modifier checks have run:
hist_field = parse_expr(hist_data, file, field_str, flags, var_name,
&n_subexprs);
...
if (hist_field->flags & HIST_FIELD_FL_VAR) {
if (hist_field->flags & (...))
goto err;
} else {
if (hist_field->flags & (...))
goto err;
}
hist_data->fields[val_idx] = hist_field;
Both checks jump past that store, and the err label returns without
freeing anything. The error unwinds to create_hist_data(), which calls
destroy_hist_data() -> destroy_hist_fields(), and that reaches a field
only by walking fields[]. A field that never got there is unreachable.
commit e0213434fe3e ("tracing: Do not let histogram values have some
modifiers") set ret to -EINVAL and fell through to the store, which left
the field owned by fields[] and freed along with the rest of hist_data.
Splitting the check into a value case and a variable case replaced that
fall-through with a goto that skips it.
With CONFIG_DEBUG_KMEMLEAK, 200 writes of
# echo 'hist:keys=prev_pid:vals=next_pid.log2' > \
events/sched/sched_switch/trigger
each correctly rejected with -EINVAL, leave 332 unreferenced objects
(63744 bytes) reported at create_hist_field(); 200 install and remove
cycles of a valid trigger leave none. A '.log2' field is two
allocations, since create_hist_field() puts the plain field in
operands[0] of the log2 field, and both are reported.
Use destroy_hist_field() rather than __destroy_hist_field() so that
operands[0] is freed as well. It returns early for HIST_FIELD_FL_VAR_REF,
which is what an operand owned by hist_data->var_refs[] needs; the
rejected field itself is never a var ref, because a var ref never carries
a modifier flag.
Cc: stable@vger.kernel.org
Fixes: e30fbc618e97 ("tracing/histograms: Allow variables to have some modifiers")
Link: https://patch.msgid.link/20260907034948.240387-1-donggeunyoo.kernel@gmail.com
Signed-off-by: Donggeun Yoo <donggeunyoo.kernel@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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create_var_ref() allocates a VAR_REF hist_field and then calls
init_var_ref() to fill it in. When that fails the field is leaked.
commit 656fe2ba85e8 ("tracing: Use hist trigger's var_ref array to destroy
var_refs") made destroy_hist_field() return early for
HIST_FIELD_FL_VAR_REF, since var refs are freed by walking the trigger's
var_refs[] array instead. create_var_ref() adds the field to that array
only after init_var_ref() has succeeded, so on this path the field is in
neither place and nothing frees it. The call was correct when it was
written, before var refs were taken out of destroy_hist_field().
init_var_ref() cannot free it either. The caller owns the field, so
init_var_ref() undoes only its own string allocations and leaves the
field alone. Freeing it there would leave create_var_ref() passing freed
memory to destroy_hist_field(), which reads its flags.
Call __destroy_hist_field(), which frees the field without consulting
the flag.
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260906133352.3815019-1-donggeunyoo.kernel@gmail.com
Fixes: 656fe2ba85e8 ("tracing: Use hist trigger's var_ref array to destroy var_refs")
Signed-off-by: Donggeun Yoo <donggeunyoo.kernel@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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Using the same variable three or more times in one hist trigger leaks the
variable reference and its strings when the trigger is removed.
commit 656fe2ba85e8 ("tracing: Use hist trigger's var_ref array to destroy
var_refs") made a trigger's var_refs[] array the only owner of a var ref:
destroy_hist_field() returns early for HIST_FIELD_FL_VAR_REF, so the field
expressions never destroy one. One entry, freed once, no count needed.
commit 8bcebc77e85f ("tracing: Fix histogram code when expression has same
var as value") then made repeated references share one object and added a
count of them. Only the increment side exists, since those expressions
still return early and never drop a reference, so __destroy_hist_field()
sees how many references were created rather than how many are left. It
frees when the decremented count is 0 or 1, so two references work and
three or more leak.
Sharing kept one array entry per object, and create_var_ref() searches and
appends within a single trigger, so nothing outside it holds the object.
Removing a trigger whose variables are still referenced is already refused
by check_var_refs() with -EBUSY. Drop the count and free unconditionally.
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260906124025.3550596-1-donggeunyoo.kernel@gmail.com
Fixes: 8bcebc77e85f ("tracing: Fix histogram code when expression has same var as value")
Signed-off-by: Donggeun Yoo <donggeunyoo.kernel@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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When a graph entry does not fit in the trace_seq, print_graph_entry()
saves it in the iterator's fgraph_data and reprints it on the next read.
The entry has already been consumed from the ring buffer by then, so the
copy is all that is left of it.
The copy is sized with iter->ent_size, which no longer describes the
saved entry but whatever entry the iterator has moved on to. The
argument count is derived from the same field, so a 72 byte entry saved
and then reprinted ahead of a 48 byte return entry loses its arguments.
Record the size next to the failure flag, so that the two are always set
together, and restore it before reprinting.
Cc: stable@vger.kernel.org
Fixes: ff5c9c576e75 ("ftrace: Add support for function argument to graph tracer")
Link: https://patch.msgid.link/20260906034406.1335316-1-donggeunyoo.kernel@gmail.com
Signed-off-by: Donggeun Yoo <donggeunyoo.kernel@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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FGRAPH_MAX_INDEX has no user, and it expands to FGRAPH_INDEX_SIZE and
FGRAPH_RET_INDEX, neither of which is defined anywhere in the tree. It
was added in that form by commit 91c46b0aa917 ("function_graph:
Implement fgraph_reserve_data() and fgraph_retrieve_data()"), which
introduced the current data word layout under new names, so anything
referencing it would have failed to build ever since.
Remove it.
Link: https://patch.msgid.link/20260905211922.1196366-1-donggeunyoo.kernel@gmail.com
Signed-off-by: Donggeun Yoo <donggeunyoo.kernel@gmail.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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dup_task_struct() copies the parent's task_struct, including ret_stack.
ftrace_graph_init_task() clears the copied function graph state, but it
currently runs after copy_exec_state().
For non-CLONE_VM forks, copy_exec_state() allocates a new task_exec_state.
If that allocation fails, copy_process() reaches bad_fork_free and
free_task() calls ftrace_graph_exit_task(). Since the child still carries
the parent's ret_stack pointer, the unwind frees the parent's active
function graph return stack. The parent subsequently accesses freed memory
from function_graph_enter_regs().
KASAN reports:
[ 22.190920] ==================================================================
[ 22.195899] BUG: KASAN: slab-use-after-free in function_graph_enter_regs+0xa76/0xb90
[ 22.200747] Write of size 8 at addr ff110000054dc0a8 by task repro/1
[ 22.205134]
[ 22.210770] CPU: 0 UID: 0 PID: 1 Comm: repro Not tainted 7.2.0-07732-g9328b3b03bdc-dirty #3 PREEMPT(lazy)
[ 22.212576] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[ 22.213750] Call Trace:
[ 22.215271] <TASK>
[ 22.216242] ? ftrace_stub_direct_tramp+0x10/0x10
[ 22.217774] dump_stack_lvl+0x4e/0x70
[ 22.220531] print_report+0x157/0x4b4
[ 22.223202] ? fixup_red_left+0x9/0x30
[ 22.224407] ? complete_report_info+0x83/0x110
[ 22.226679] ? function_graph_enter_regs+0xa76/0xb90
[ 22.228084] kasan_report+0xce/0x100
[ 22.230109] ? function_graph_enter_regs+0xa76/0xb90
[ 22.232860] ? stack_trace_save+0x4/0xd0
[ 22.234156] function_graph_enter_regs+0xa76/0xb90
[ 22.236090] ? kasan_save_stack+0x30/0x50
[ 22.237752] ? __pfx_function_graph_enter_regs+0x10/0x10
[ 22.238694] ? ring_buffer_lock_reserve+0x345/0xf80
[ 22.239628] ? stack_trace_save+0x4/0xd0
[ 22.242121] ? stack_trace_save+0x4/0xd0
[ 22.243588] ftrace_graph_func+0xda/0x160
[ 22.245362] ? ftrace_stub_direct_tramp+0x10/0x10
[ 22.246520] 0xffffffffa0000095
[ 22.250528] ? stack_trace_save+0x9/0xd0
[ 22.251757] ? ring_buffer_unlock_commit+0x11d/0x5c0
[ 22.253152] stack_trace_save+0x9/0xd0
[ 22.254264] kasan_save_stack+0x30/0x50
[ 22.273631] kasan_save_track+0x14/0x30
[ 22.276763] kasan_save_free_info+0x3b/0x70
[ 22.278296] __kasan_slab_free+0x43/0x70
[ 22.280157] kmem_cache_free+0xbf/0x3b0
[ 22.282963] ? ftrace_stub_direct_tramp+0x10/0x10
[ 22.284001] free_task+0xa2/0x160
[ 22.285699] ? ftrace_stub_direct_tramp+0x10/0x10
[ 22.286752] copy_process+0x2aae/0x7bc0
Initialize the child function graph state immediately after
dup_task_struct(), before the first fallible operation.
Cc: stable@vger.kernel.org
Fixes: 6b1c66c9cca9 ("exec_state: relocate dumpable information")
Reviewed-by: Bradley Morgan <include@grrlz.net>
Link: https://patch.msgid.link/20260822195321.962383-2-Jeremy.Jean@oss.cyber.gouv.fr
Assisted-by: Codex:gpt-5
Signed-off-by: Jérémy Jean <Jeremy.Jean@oss.cyber.gouv.fr>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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destroy_user_event() destroys the event's fields before attempting to
remove the trace event call. If user_event_set_call_visible() fails,
e.g. because the event is still enabled and trace_remove_event_call()
returns -EBUSY, the event is left registered with an irreversibly
destroyed field list. Any subsequent interaction with the event then
operates on an empty field list while it is still fully visible in
tracefs.
Move the field destruction after the call removal, and splice the
field list back onto the event when the removal fails so the event
remains in a consistent state.
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260904115223.2976446-1-bsdhenrymartin@gmail.com
Fixes: 7f5a08c79df35 ("user_events: Add minimal support for trace_event into ftrace")
Signed-off-by: Henry Martin <bsdhenrymartin@gmail.com>
Reviewed-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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Rearming a queued timer with nonzero slack can leave the timerqueue out
of order. remove_and_enqueue_same_base() checks the new soft expiry
against its neighbours' hard expiries, then stores the new hard expiry
in the node without requeueing it.
For example, with A at 10 and B at 20, rearming A at 11 with slack 30
passes the neighbour check but leaves A's hard expiry of 41 before B's
20. The same function also caches the soft expiry in base->expires_next
when updating or inserting the first timer, giving next-event selection
an earlier deadline than the queue head's hard expiry.
Set the timer expiry before handling the queue. Use its stored hard
expiry for the in-place ordering check and both updates to
base->expires_next.
The early update is safe because remove_and_enqueue_same_base() runs
with base->cpu_base->lock held. The lock keeps the queue stable while
hrtimer_can_update_in_place() checks the new expiry against both
neighbours. If the check fails, timerqueue_linked_del() removes the node
without comparing expiry values before it is reinserted.
Fixes: eddffab8282e3 ("hrtimer: Keep track of first expiring timer per clock base")
Fixes: 343f2f4dc5425 ("hrtimer: Try to modify timers in place")
Signed-off-by: Andrea Parri <parri.andrea@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Assisted-by: LLM
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260910143442.2018-1-parri.andrea@gmail.com
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git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl
Pull sysctl fix from Joel Granados:
"This fell through the cracks during the latest merge window. There are
no more CONFIG_PROC_SYSCTL uses after this fix:
- Replace CONFIG_PROC_SYSCTL with CONFIG_SYSCTL
CONFIG_SYSCTL is the config string that controls sysctl subsys"
* tag 'sysctl-7.03-fixes-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl:
syscall_user_dispatch: Use CONFIG_SYSCTL for sysctl guard
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