In 'struct trace_event_call', the 'module' pointer and the 'refcnt'
atomic variable share the same memory space in a union. For dynamic
events, the union member is 'refcnt', which acts as an active
reference counter.
When a dynamic event (such as kprobe, uprobe, fprobe, eprobe, or
wprobe) has a non-zero reference count (e.g. due to active event
triggers or perf attachments), its 'call->module' evaluates to a
small non-zero integer instead of NULL.
When filtering or setting events for a specific module (e.g., writing
':mod:<module>' to 'set_event'), the code in
'__ftrace_set_clr_event_nolock()' and 'update_event_fields()' reads
'call->module' directly without checking whether the event is dynamic.
This causes the kernel to treat the small integer (refcnt) as a
'struct module' pointer, leading to a NULL/invalid pointer dereference
(Oops) when dereferencing the module name.
Fix this by ensuring that the 'TRACE_EVENT_FL_DYNAMIC' flag is checked
before treating 'call->module' as a valid pointer in these code paths.
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/178425670947.84440.11344393611899824907.stgit@devnote2
Fixes: 4c86bc531e ("tracing: Add :mod: command to enabled module events")
Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
A global subprogram argument tagged __arg_nonnull is set up as a
non-nullable PTR_TO_MEM. However the verifier does not check against a
scalar NULL, leading to real NULL pointer dereference. Reject it as
well.
Fixes: 94e1c70a34 ("bpf: support 'arg:xxx' btf_decl_tag-based hints for global subprog args")
Signed-off-by: Amery Hung <ameryhung@gmail.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://patch.msgid.link/20260723221815.367797-1-ameryhung@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
The mmiotrace tracer was added May 12th 2008. At that time, resources
created in pipe_open() could not be freed because there was not
pipe_close function pointer of the tracer. The pipe_close function pointer
was added in December 7th, 2009, but the mmiotrace tracer was not updated.
mmio_pipe_open() allocates a header_iter and takes a pci_dev reference
when trace_pipe is opened. mmio_close() frees them, but it was only
wired to the tracer's .close callback.
tracing_release_pipe() invokes .pipe_close, not .close, when the
trace_pipe file is released. As a result, closing trace_pipe with the
mmiotrace tracer active leaked the header_iter allocation and left a
stale pci_dev reference.
Set .pipe_close to mmio_close, matching how function_graph wires both
callbacks to the same handler.
Note, if the trace_pipe is read to completion, it will clean up the
resources, but if one were to run:
# head -n 1 /sys/kernel/tracing/trace_pipe
VERSION 20070824
Over and over again, it would trigger a massive leak.
Cc: stable@vger.kernel.org
Fixes: c521efd170 ("tracing: Add pipe_close interface)
Link: https://patch.msgid.link/20260715143604.14481-1-gaikwad.dcg@gmail.com
Signed-off-by: deepakraog <gaikwad.dcg@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
remote_events_dir_enable_write() ignores the return value from
trace_remote_enable_event(). If a remote rejects an event state change,
the write therefore reports success even though the affected event remains
in its previous state.
Keep trying all events, but retain and return the first error. This matches
__ftrace_set_clr_event_nolock(), which permits partial updates while
notifying userspace when an operation fails.
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260715074455.3897-1-liu.yun@linux.dev
Fixes: 775cb093bc ("tracing: Add events/ root files to trace remotes")
Assisted-by: Codex:gpt-5.6-sol
Signed-off-by: Jackie Liu <liuyun01@kylinos.cn>
Reviewed-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
page_va[] is annotated __counted_by(nr_page_va), so nr_page_va must
cover an index before that element is accessed. The allocation loop
writes page_va[id] while nr_page_va is still id and increments it only
afterwards, so every write is one element past the declared count.
The store is out of bounds with respect to the annotation: a build with
CONFIG_UBSAN_BOUNDS on a toolchain that honours __counted_by
(clang >= 20.1, gcc >= 15.1) flags it as an array-index overflow.
Increment nr_page_va before writing the element it now covers. A failed
allocation then leaves the slot counted but NULL; the error path frees
it with free_page(0), which is a no-op.
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260713072823.2668323-1-fuad.tabba@linux.dev
Fixes: 96e43537af ("tracing: Introduce trace remotes")
Signed-off-by: Fuad Tabba <fuad.tabba@linux.dev>
Reviewed-by: Vincent Donnefort <vdonnefort@google.com>
Tested-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Commit b0473dcd4b ("smp: Improve smp_call_function_single()
CSD-lock diagnostics") changed smp_call_function_single() so that,
when CSD lock debugging is enabled, async !wait calls use the
destination CPU csd_data. That improves diagnostics, but it also removes
the single-writer property that made the old csd_lock() safe: multiple
CPUs can now prepare the same destination CPU CSD concurrently.
csd_lock() currently waits for CSD_FLAG_LOCK to clear and then sets the
bit with a non-atomic read-modify-write. Two senders can both see an
unlocked CSD, set the bit, overwrite the callback fields, and enqueue
the same llist node. Re-adding a node that is already the queue head can
make node->next point to itself, leaving the target CPU stuck walking
call_single_queue. Later synchronous work, such as a TLB shootdown, can
then remain queued and trigger soft-lockup warnings or panics.
Keep the single csd_lock() implementation, but when CSD lock debugging is
enabled, acquire CSD_FLAG_LOCK with try_cmpxchg_acquire(). This makes the
destination CPU CSD a real atomic lock in the only configuration where it
can be shared by multiple remote senders, while preserving the existing
non-debug fast path.
Fixes: b0473dcd4b ("smp: Improve smp_call_function_single() CSD-lock diagnostics")
Signed-off-by: Chuyi Zhou <zhouchuyi@bytedance.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260716004539.13983-2-paulmck@kernel.org
Commit b0473dcd4b ("smp: Improve smp_call_function_single()
CSD-lock diagnostics") made smp_call_function_single() use the destination
CPU's csd_data when CSD lock debugging is enabled. That lets the debug code
associate a stuck CSD lock with the target CPU, but it also means the CPU
argument is used in per_cpu_ptr() before generic_exec_single() has a chance
to validate it.
This becomes unsafe when smp_call_function_any() cannot find an online CPU
in the supplied mask. In that case the selected CPU can be nr_cpu_ids, and
the !wait path calls get_single_csd_data(cpu) before generic_exec_single()
returns -ENXIO. With csdlock_debug_enabled set, that indexes the per-CPU
offset array with an invalid CPU number.
Use the destination CPU's csd_data only when the CPU number is within
nr_cpu_ids. For invalid CPU numbers, fall back to the local CPU's csd_data
and let generic_exec_single() perform the existing validation and return
-ENXIO.
Fixes: b0473dcd4b ("smp: Improve smp_call_function_single() CSD-lock diagnostics")
Signed-off-by: Chuyi Zhou <zhouchuyi@bytedance.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Acked-by: Muchun Song <muchun.song@linux.dev>
Link: https://patch.msgid.link/20260716004539.13983-1-paulmck@kernel.org
Pull liveupdate fix from Mike Rapoport:
- Fix validation of LIVEUPDATE_SESSION_GET_NAME ioctl argument caused
by a wrong resolution of a merge conflict during the last merge
window
* tag 'liveupdate-fixes-2026-07-22' of git://git.kernel.org/pub/scm/linux/kernel/git/liveupdate/linux:
liveupdate: fix GET_NAME ioctl argument validation
SCX's built-in idle CPU tracking is imperfect and can be out-of-sync
with the actual idle state of CPUs, especially immediately after
enabling SCX due to scx_idle_enable() marking all online CPUs idle.
scx_select_cpu_dfl() skips marking the selected CPU as busy if
the selected CPU is the waker CPU in the SCX_WAKE_SYNC case.
If the waker CPU was marked idle by SCX, it will still be marked idle
after CPU selection and potentially even after switching to the wakee.
In the allowed_cpus selftest, this can manifest as the test failing with
the following message in dmesg:
allowed_cpus.bpf.c:21: CPU 0 should be marked as busy
This patch explicitly marks the waker CPU as busy. With this patch,
the test failure no longer reproduces. There are still some pretty
unlikely races that could make the test fail (e.g. pick_task_idle()
marking the selected CPU idle between selection and validation), but
these can't be fixed easily.
Signed-off-by: Kuba Piecuch <jpiecuch@google.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Commit 16a03c71bb ("cpufreq: schedutil: Merge initialization code of
sg_cpu in single loop") merged the per-CPU initialization and the
utilization-hook registration into a single loop in sugov_start().
For a shared cpufreq policy this re-introduces the race originally fixed
by commit ab2f7cf141 ("cpufreq: schedutil: Fix sugov_start() versus
sugov_update_shared() race").
The scheduler's util path reaches the hook under RCU-sched and never takes
policy->rwsem, so the rwsem held across sugov_start() cannot serialize the
two. Once the first CPU's hook is published, sugov_update_shared() may run
and, via sugov_next_freq_shared(), read/write each sibling sugov_cpu
(iowait_boost, util, bw_min, ...) concurrently with the memset() still
initializing them, with no lock common to both sides: the update side holds
sg_policy->update_lock while the init side holds only policy->rwsem, which
the scheduler's util path never takes.
The walk only accesses scalar members, never a pointer like ->sg_policy,
so it does not crash today; it merely uses stale (or zero on first start)
values that skew the frequency selection and tracepoints. It is still a
genuine data race, and a latent crash once any pointer member is
dereferenced there.
Restore the two-phase approach: initialize all per-CPU structures first,
and only then publish the per-CPU utilization update hooks.
Fixes: 16a03c71bb ("cpufreq: schedutil: Merge initialization code of sg_cpu in single loop")
Cc: stable@vger.kernel.org
Signed-off-by: Zhongqiu Han <zhongqiu.han@oss.qualcomm.com>
Reviewed-by: Christian Loehle <christian.loehle@arm.com>
Link: https://patch.msgid.link/20260716115159.848403-1-zhongqiu.han@oss.qualcomm.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
eprobe_dyn_event_match() checks if the target event system in argv[0]
matches ep->event_system using strncmp(ep->event_system, argv[0], len).
However, if ep->event_system is longer than len (e.g. "eprobes" vs
"ep/event"), strncmp() still returns 0 because the first len characters
match.
Check that ep->event_system[len] is '\0' to ensure exact system name
matching.
Link: https://lore.kernel.org/all/178454235856.290363.14872590900774231133.stgit@devnote2/
Fixes: 7d5fda1c84 ("tracing: Fix event probe removal from dynamic events")
Cc: stable@vger.kernel.org
Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
In __set_print_fmt(), LEN_OR_ZERO is defined as (len ? len - pos : 0).
If len is non-zero but smaller than pos, len - pos evaluates to a negative
integer. When passed as a size argument to snprintf(), this negative value
is cast to a large unsigned size_t, bypassing buffer size limits.
Ensure len > pos before subtracting to avoid integer underflow.
Link: https://lore.kernel.org/all/178454234934.290363.15247317871499514139.stgit@devnote2/
Fixes: 5bf652aaf4 ("tracing/probes: Integrate duplicate set_print_fmt()")
Cc: stable@vger.kernel.org
Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
If trace_probe_log.argc is 0 in __trace_probe_log_err(), the loop
constructing the command string will not execute and p will remain equal to
command. Writing to *(p - 1) will cause an out-of-bounds access before
command. This should not happen, but better to be treated.
Reject if trace_probe_log.argc is 0.
Link: https://lore.kernel.org/all/178454233992.290363.18323091580600697731.stgit@devnote2/
Fixes: ab105a4fb8 ("tracing: Use tracing error_log with probe events")
Cc: stable@vger.kernel.org
Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
In trace_probe_match_command_args(), a stack buffer buf[MAX_ARGSTR_LEN + 1]
(256 bytes) is used to format "<name>=<comm>". However, since name can
be up to 32 bytes (MAX_ARG_NAME_LEN) and comm up to 255 bytes
(MAX_ARGSTR_LEN), the formatted string can exceed 256 bytes and get
truncated by snprintf(), causing spurious argument matching failures.
Instead of formatting into a temporary buffer on stack, compare the
argument name, the '=' delimiter, and the comm expression directly.
Link: https://lore.kernel.org/all/178454233010.290363.10428767141343428804.stgit@devnote2/
Fixes: eb5bf81330 ("tracing/kprobe: Add per-probe delete from event")
Cc: stable@vger.kernel.org
Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Root enable and scx_post_fork() enable a task only if it's on the ext class.
Tasks on other classes, possible under an SCX_OPS_SWITCH_PARTIAL root, are
left READY and enabled by switching_to_scx() when they switch over. The sub
enable-commit pass and the sub-disable re-home loop enable unconditionally,
so a fair-class READY task in the subtree becomes ENABLED while not on
sched_ext. A later switch to SCHED_EXT then trips the task state validation
WARN (ENABLED with the previous state not READY) and calls ops.enable() a
second time.
Gate scx_enable_task() on the task's class in both loops.
Fixes: 337ec00b1d ("sched_ext: Implement cgroup sub-sched enabling and disabling")
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Andrea Righi <arighi@nvidia.com>
A sub-scheduler enable can fail before scx_link_sched() links the sched into
the hierarchy, e.g. when the parent is already being disabled, and cleanup
still runs the full scx_sub_disable().
That is racy against root disable: drain_descendants() is the only ordering
between a sub's disable-time task walk and root disable's all-task teardown,
and an unlinked sub is invisible to it. Root's teardown can thus run between
the never-linked sub's drain and its walk, exiting every task to no
scheduler.
The walk then trips the membership WARN and re-homes the exited tasks onto
the dying hierarchy, a use-after-free.
Skip the cgroup ownership reset and the task walk if @sch was never linked,
indicated by the empty ->sibling as unlinking only happens later in the same
function. The membership WARN remains valid: a linked sub is always waited
on by an ancestor's drain.
Fixes: 337ec00b1d ("sched_ext: Implement cgroup sub-sched enabling and disabling")
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Andrea Righi <arighi@nvidia.com>
scx_cgroup_lock() write-locks scx_cgroup_ops_rwsem and then takes
cgroup_lock(), which can deadlock through kernfs:
scx enable/disable cgroup rmdir cpu.weight write
------------------ ------------ ----------------
cgroup_lock()
percpu_down_write(rwsem)
cgroup_lock()
kernfs_get_active()
percpu_down_read(rwsem)
kernfs_drain()
The enable path waits for the rmdir to release cgroup_mutex. The rmdir,
deactivating the cpu controller's files, waits in kernfs_drain() for the
write's active reference. The write, in scx_group_set_weight(), waits for
the rwsem behind the pending writer.
Take cgroup_lock() first. The set_* paths take no cgroup locks inside the
read side, so a pending write-lock then only waits for read sections that
always run to completion, and no dependency from the rwsem back to
cgroup_mutex remains.
Fixes: a5bd6ba30b ("sched_ext: Use cgroup_lock/unlock() to synchronize against cgroup operations")
Cc: stable@vger.kernel.org # v6.18+
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Andrea Righi <arighi@nvidia.com>
The p->scx.disallow revert assumes the root enable path, where the switching
loop reads the reverted policy right afterwards and leaves the task off SCX.
The sub-scheduler disable path also reaches it when re-initializing the
returned tasks on a root parent. Nothing reads the policy there: the task is
enabled on root anyway and keeps running on the ext class with a silently
rewritten policy.
Kill the sched instead, matching the fork and non-root branches, and update
the disallow documentation, which equated !fork with the load path and
pointed at a stale debugfs path for nr_rejected.
Fixes: 337ec00b1d ("sched_ext: Implement cgroup sub-sched enabling and disabling")
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Andrea Righi <arighi@nvidia.com>
Pull bpf fixes from Kumar Kartikeya Dwivedi:
- Fix a UAF in socket clone early bailout paths (Matt Bobrowski)
- Reject unhashed UDP sockets on sockmap update to prevent refcount
leaks (Michal Luczaj)
- Account for receive queue data in FIONREAD on sockmap sockets without
a verdict program (Mattia Meleleo)
- Reject negative constant offsets for verifier buffer pointers (Sun
Jian)
- Fix for tracing of kfuncs with implicit arguments (Ihor Solodrai)
* tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
selftests/bpf: Cover tracing implicit kfunc args
bpf: Fix tracing of kfuncs with implicit args
selftests/bpf: Cover negative buffer pointer offsets
bpf: Reject negative const offsets for buffer pointers
selftests/bpf: Test FIONREAD on a sockmap socket without a verdict program
bpf, sockmap: Account for receive queue in FIONREAD without a verdict program
selftests/bpf: Fail unbound UDP on sockmap update
selftests/bpf: Adapt sockmap update error handling
bpf, sockmap: Reject unhashed UDP sockets on sockmap update
selftests/bpf: Ensure UDP sockets are bound
bpf: Fix UAF in sock clone early bailouts
A kfunc marked with KF_IMPLICIT_ARGS flag takes implicit arguments
(such as bpf_prog_aux) that the verifier injects at load time.
resolve_btfids strips those from the kfunc's BTF-visible prototype and
keeps the real kernel ABI in a counterpart _impl prototype [1].
fentry/fexit/fmod_ret/fsession programs may attach to the BPF kernel
functions, including those with implicit args. However
bpf_check_attach_target() and bpf_check_attach_btf_id_multi() extract
the struct btf_func_model from the wrong BTF prototype of the
kfunc. The btf_func_model is later read to construct the trampoline,
which then causes the injected implicit argument to be clobbered and
the kfunc dereferencing garbage.
Add btf_attach_func_proto() to resolve the real ABI prototype of the
kfunc the way the call site does: by looking up the _impl prototype
for a KF_IMPLICIT_ARGS kfunc. Use it at both attach-target model
construction sites.
To enable this, make two supporting changes:
* pass bpf_verifier_log instead of bpf_verifier_env to
find_kfunc_impl_proto(), so it can be reused from the attach path
* add btf_kfunc_check_flag() to test a flag across all of a kfunc's
hook sets, because a program attaching to a kfunc is not in the
kfunc's call-set
KF_IMPLICIT_ARGS must be consistent across the sets, so
btf_kfunc_check_flag() returns -EINVAL on inconsistency.
btf_kfunc_check_flag() reads the kfunc's flags from the target's
kfunc_set_tab. For a module BTF that table is stable only after the
module is live, so take a module reference around the read, mirroring
how the kfunc call path gates the same lookup with btf_try_get_module().
The remaining call sites of btf_distill_func_proto() are safe as
is. The BPF_TRACE_ITER case distills a registered iterator's
prototype, and bpf_struct_ops_desc_init() distills the
function-pointer members of a struct_ops type. Neither is a kfunc, and
so can't have implicit arguments.
[1] https://lore.kernel.org/all/20260120222638.3976562-1-ihor.solodrai@linux.dev/
Fixes: 64e1360524 ("bpf: Verifier support for KF_IMPLICIT_ARGS")
Reported-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Link: https://github.com/sched-ext/scx/issues/3687#issuecomment-4906694106
Link: https://patch.msgid.link/20260713235223.1639022-2-ihor.solodrai@linux.dev
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
LIVEUPDATE_SESSION_GET_NAME was developed in the liveupdate/next branch
while the session type validation change was carried in liveupdate-fixes.
When the conflict between the two branches was resolved, the GET_NAME
operation descriptor picked up the structure and last member from
RETRIEVE_FD.
This makes both its known size and minimum size 16 bytes rather than 72.
A zero-initialized request still succeeds because luo_session_get_name()
writes the full name before luo_ucmd_respond() copies the full GET_NAME
response to userspace. However, copy_struct_from_user() treats the
output-only name field as unknown trailing data and rejects the request
with -E2BIG if any byte in that field is nonzero.
Use the GET_NAME structure and its name field in the descriptor.
Link: https://lore.kernel.org/all/ahWlYXNjGUbkKoHy@sirena.org.uk/
Assisted-by: Codex:gpt-5.6-sol
Reviewed-by: Pratyush Yadav (Google) <pratyush@kernel.org>
Signed-off-by: Jackie Liu <liuyun01@kylinos.cn>
Link: https://patch.msgid.link/20260716012607.22020-1-liu.yun@linux.dev
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
psi_schedule_rtpoll_work() is called locklessly from the scheduler hotpath
and can race psi_trigger_destroy() taking down the last rtpoll trigger under
rtpoll_trigger_lock:
psi_schedule_rtpoll_work() psi_trigger_destroy()
rcu_read_lock();
task = rcu_dereference(rtpoll_task);
rcu_assign_pointer(rtpoll_task, NULL);
timer_delete(&rtpoll_timer);
mod_timer(&rtpoll_timer, ...);
rcu_read_unlock();
synchronize_rcu();
kthread_stop(task_to_destroy);
The group can then be freed with the re-armed timer still pending, and
poll_timer_fn() runs on freed memory.
461daba06b ("psi: eliminate kthread_worker from psi trigger scheduling
mechanism") deleted the timer synchronously after the synchronize_rcu(),
which prevented this but raced trigger creation instead: the deletion could
cancel the timer that a new trigger set armed during the grace period and,
as creation also reinitialized the timer at the time, corrupt it.
8f91efd870 ("psi: Fix race between psi_trigger_create/destroy") moved the
initialization into group_init() and the deletion into the locked section,
trading the creation races for the window above.
Neither placement in the destruction path works. A pending timer firing
while the group is alive is harmless though. poll_timer_fn() just wakes the
rtpoll waitqueue and doesn't re-arm itself. Bind the timer to the group's
lifetime instead and shut it down in psi_cgroup_free(). Nothing can arm it
by then. timer_shutdown_sync() because the timer is never armed again.
Fixes: 8f91efd870 ("psi: Fix race between psi_trigger_create/destroy")
Cc: stable@vger.kernel.org # v5.10+
Reported-by: Sashiko AI <sashiko-bot@kernel.org>
Closes: https://lore.kernel.org/all/20260711000434.36C4A1F000E9@smtp.kernel.org/
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Tested-by: Matt Fleming <mfleming@cloudflare.com>
Acked-by: Suren Baghdasaryan <surenb@google.com>
a5b98009f1 ("sched/psi: fix race between file release and pressure write")
made pressure_write() hold cgroup_mutex across psi_trigger_create(), which
forks the psimon kthread for the first rtpoll trigger. As kthread creation
depends on the whole fork path, the commit inadvertently created a lot of
unwanted locking dependencies from cgroup_mutex.
sched_ext got hit by one: its enable path blocks forks and then grabs
cgroup_mutex, so a pressure write racing a scheduler enable deadlocks, with
every other fork piling up behind.
Fix it by splitting trigger creation so that the worker is forked with
cgroup_mutex dropped and the kernfs active reference left broken. The latter
matters because rmdir and cgroup.pressure writes drain active references
under cgroup_mutex. Publishing the trigger last keeps error reporting
synchronous and preserves the of->priv lifetime rules.
The trigger registered in the first stage pins the group's rtpoll machinery
across the unlocked window, leaving only creation races to resolve. The
catch-up poll on installation covers scheduling attempts dropped while there
was no worker.
v2: Retagged sched/psi (was cgroup).
Fixes: a5b98009f1 ("sched/psi: fix race between file release and pressure write")
Cc: stable@vger.kernel.org
Cc: Edward Adam Davis <eadavis@qq.com>
Cc: Chen Ridong <chenridong@huaweicloud.com>
Reported-by: Matt Fleming <mfleming@cloudflare.com>
Closes: https://lore.kernel.org/all/20260710100441.2653477-1-matt@readmodwrite.com/
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Tested-by: Matt Fleming <mfleming@cloudflare.com>
Acked-by: Suren Baghdasaryan <surenb@google.com>
The verifier rejects variable offsets for PTR_TO_TP_BUFFER and PTR_TO_BUF
accesses, but it currently accepts a constant negative offset produced by
pointer arithmetic.
Commit 022ac07508 ("bpf: use reg->var_off instead of reg->off for
pointers") moved constant pointer offsets from reg->off to reg->var_off.
However, __check_buffer_access() continued to check only the instruction
offset. An access with reg->var_off equal to -8 and an instruction offset
of zero therefore passes verification.
For writable raw tracepoints, the access end is also calculated from the
unsigned reg->var_off.value. An eight-byte access starting at -8 wraps
the calculated end to zero, allowing the program to load and attach
without increasing max_tp_access.
After ensuring that reg->var_off is constant, calculate the effective
access start using signed arithmetic and reject it when it is negative.
Use the validated start to calculate the access end for both
PTR_TO_TP_BUFFER and PTR_TO_BUF.
Fixes: 022ac07508 ("bpf: use reg->var_off instead of reg->off for pointers")
Signed-off-by: Sun Jian <sun.jian.kdev@gmail.com>
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
Cc: stable@vger.kernel.org # 5.2.0
Link: https://patch.msgid.link/20260714093846.18159-2-sun.jian.kdev@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Pull cgroup fixes from Tejun Heo:
- A cpuset that never set its memory nodes could divide by zero when a
task's mempolicy rebinds on CPU hotplug. Rebind against the effective
nodes, which are always populated
- Documentation fixes for memory.stat, io.stat, and the misc and v1
RDMA controllers
* tag 'cgroup-for-7.2-rc3-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
Docs/admin-guide/cgroup-v2: note blkcg_debug_stats gates io.latency stats
Docs/admin-guide/cgroup-v1: document rdma.peak, rdma.events and rdma.events.local
Docs/admin-guide/cgroup-v2: drop stale misc interface file count
cgroup/cpuset: rebind mm mempolicy to effective_mems, not mems_allowed
Docs/admin-guide/cgroup-v2: fix memory.stat doc details
Pull sched_ext fixes from Tejun Heo:
- Lifecycle fixes for the new sub-scheduler support: two
use-after-frees and an enable-failure path that left a
half-initialized sub-scheduler linked.
- Two dispatch-path locking bugs: a spurious scheduler abort from a
migration race, and a lockdep splat from stale runqueue-lock
tracking.
- Callback and task-state fixes: stale scheduler-owned state on a task
leaving SCX, a weight callback running after disable, and a bogus
warning on core-scheduling forced idle.
- On nohz_full, finite-slice tasks could miss the tick that expires
their slice. Enable it when such a task is picked, with a selftest.
- Smaller fixes: userspace CPU-mask helpers, ratelimited deprecation
warnings, docs and a sparse annotation.
* tag 'sched_ext-for-7.2-rc3-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext:
sched_ext: Skip ops.set_weight() for disabled tasks
tools/sched_ext: scx - Fix cmask_subset(), cmask_equal() and cmask_weight()
sched_ext: Fix premature ops->priv publication in scx_alloc_and_add_sched()
sched_ext: Record an error on errno-only sub-enable failure
selftests/sched_ext: Verify nohz_full tick behavior
sched_ext: Enable tick for finite slices on nohz_full
sched_ext: Preserve rq tracking across local DSQ dispatch
sched_ext: Documentation: Fix ops table header reference
sched_ext: Don't warn on core-sched forced idle in put_prev_task_scx()
sched_ext: Pin parent scx_sched across a child sub-scheduler's lifetime
sched_ext: Annotate ksyncs with __rcu in alloc/free_kick_syncs()
sched_ext: Check remote rq eligibility under task's rq lock
sched_ext: Reset dsq_vtime and slice when a task leaves SCX
sched_ext: Avoid flooding the log with deprecation warnings
Pull tracing fixes from Steven Rostedt:
- Free field in error path of synthetic event parse
In __create_synth_event() the field was allocated but was not freed
in the error path
- Fix ring_buffer_event_length() on 8 byte aligned architectures
On architectures with CONFIG_HAVE_64BIT_ALIGNED_ACCESS set to y, the
ring_buffer_event_length() may return the wrong size. This is because
archs with that config set will always use the "big event meta
header" as that is 8 bytes keeping the payload 8 bytes aligned, even
when a 4 byte header could hold the size of the event
But ring_buffer_event_length() doesn't take this into account and
only subtracts 4 bytes for the meta header in the length when it
should have subtracted 8 bytes
- Have osnoise wait for a full rcu synchronization on unregister
osnoise_unregister_instance() used to call synchronize_rcu() before
freeing its copy of the instance but was switched to kfree_rcu(). The
osniose tracer has code that traverses the instances that it uses,
and inst is just a pointer to that instance. By using kfree_rcu()
instead of synchronize_rcu(), the instance that the inst pointer is
pointing to can be freed while the osnoise code is still referencing
it
That is, a rmdir on an instance first unregisters the tracer. When
the unregister finishes, the rmdir expects that the tracer is
finished with the instance that it is using. By putting back the
synchronize_rcu() in osnoise_unregister_instance() the unregistering
of osnoise will now return when all the users of the instance have
finished
- Remove an unused setting of "ret" in tracing_set_tracer()
- Fix ring_buffer_read_page() copying events
The commit that changed ring_buffer_read_page() to show dropped
events from the buffer itself, split the "commit" variable between
the commit value (with flags) and "size" that holds the size of the
sub-buffer. A cut and paste error changed the test of the reading
from checking the size of the buffer to the size of the event causing
reads to only read one event at a time
- Make tracepoint_printk a static variable
When the tracing sysctl knobs were move from sysctl.c to trace.c, the
variable tracepoint_printk no longer needed to be global. Make it
static
- Fix some typos
- Fix NULL pointer dereference in func_set_flag()
The flags update of the function tracer first checks if the value of
the flag is the same and exits if they are, and then it checks if the
current tracer is the function tracer and exits if it isn't. The
problem is that these checks need to be in a reversed order, as if
the tracer isn't the function tracer, then the flag being checked may
not exist. Reverse the order of these checks
- Fix ufs core trace events to not dereference a pointer in TP_printk()
The TP_printk() part of the TRACE_EVENT() macro is called when the
user reads the "trace" file. This can be seconds, minutes, hours,
days, weeks, and even months after the data was recorded into the
ring buffer. Thus, saving a pointer to an object into the ring buffer
and then dereferencing it from TP_printk() can cause harm as the
object the pointer is pointing to may no longer exist
Fix all the trace events in ufs core to save the device name in the
ring buffer instead of dereferencing the device descriptor from
TP_printk()
- Prevent out-of-bound reads in glob matching of trace events
The filter logic of events allows simple glob logic to add wild cards
to filter on strings. But some events have fields that may not have a
terminating 'nul' character. This may cause the glob matching to go
beyond the string. Change the logic to always pass in the length of
the field that is being matched
- Add no-rcu-check version of trace_##event##_enabled()
The trace_##event##_enabled() usually wraps trace events to do extra
work that is only needed when the trace event is enabled. But this
can hide events that are placed in locations where RCU is not
watching, and can make lockdep not see these bugs when the event is
not enabled
The trace_##event##_enabled() was updated to always test to make sure
RCU is watching to catch locations that may call events without RCU
being active
This caused a false positive for the irq_disabled() and related
events. As that use trace_irq_disabled_enabled() to force RCU to be
watching when the event is enabled via the ct_irq_enter() function,
calls the event, and then calls ct_irq_exit() to put RCU back to its
original state
The trace_irq_disabled_enabled() should not trigger a warning when
RCU is not watching because the code within its block handles the
case properly. Make a __trace_##event##_enabled() version for this
event to use that doesn't check RCU is watching as it handles the
case when it isn't
- Fix use-after-free in user_event_mm_dup()
When the enabler is removed from the link list, it is freed
immediately. But it is protected via RCU and needs to be freed after
an RCU grace period. Use queue_rcu_work() so that the event_mutex can
also be taken as user_event_put() takes the mutex on the last
reference is released
- Free type string in error path of parse_synth_field()
There's an error path in parse_synth_field() where the allocated type
string is not freed
- Add selftest that tests deferred event teardown
- Fix leak in error path of trace_remote_alloc_buffer()
If page allocation fails, the desc->nr_cpus is not incremented for
the current CPU and the allocations done for it are not freed
- Fix allocation length in trace_remote_alloc_buffer()
The logic to calculate the struct_len was doing a double count and
setting the value too large. Calculate the size upfront to fix the
error and simplify the logic
- Fix sparse CPU masks in ring_buffer_desc()
If there are sparse CPUs (gaps in the numbering), the
ring_buffer_desc() will fail as it tests the CPU number against the
number of CPUs that are used
* tag 'trace-v7.2-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
ring-buffer: Allow sparse CPU masks in ring_buffer_desc()
tracing/remotes: Fix struct_len in trace_remote_alloc_buffer()
tracing/remotes: Fix leak in trace_remote_alloc_buffer() error path
selftests/user_events: Wait for deferred event teardown after unregister
tracing/synthetic: Free type string on error path
tracing/user_events: Fix use-after-free in user_event_mm_dup()
tracing: Add a no-rcu-check version of trace_##event##_enabled()
tracing: Prevent out-of-bounds read in glob matching
ufs: core: tracing: Do not dereference pointers in TP_printk()
tracing: Fix NULL pointer dereference in func_set_flag()
samples: ftrace: Fix typos in benchmark comment
tracing: Make tracepoint_printk static as not exported
ring-buffer: Fix ring_buffer_read_page() copying only one event per page
tracing: Remove unused ret assignment in tracing_set_tracer()
tracing/osnoise: Call synchronize_rcu() when unregistering
ring-buffer: Fix event length with forced 8-byte alignment
tracing/synthetic: Free pending field on error path
Pull perf events fixes from Ingo Molnar:
- Fix SVM #GP on AMD CPUs that LBR but not BRS (Sandipan Das)
- Fix UAF bug in the perf AUX code (Lee Jia Jie)
- Fix address leakage in the AMD LBR code (Sandipan Das)
- Fix address leakage in the AMD BRS code (Sandipan Das)
* tag 'perf-urgent-2026-07-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/x86/amd/brs: Fix kernel address leakage
perf/x86/amd/lbr: Fix kernel address leakage
perf/aux: Fix page UAF in map_range()
perf/x86/amd/core: Avoid enabling BRS from the SVM reload path
Pull timer fix from Ingo Molnar:
- Fix a subtle posix-cpu-timers vs. exec() race, which
unearthed other races in the area (Thomas Gleixner)
* tag 'timers-urgent-2026-07-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
posix-cpu-timers: Prevent UAF caused by non-leader exec() race
Pull audit fixes from Paul Moore:
"Two relatively small audit patches to fix potential data races with
the main audit backlog queue as well as possible integer overflows
when logging data as hex strings"
* tag 'audit-pr-20260710' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit:
audit: fix potential integer overflow in audit_log_n_hex()
audit: Fix data races of skb_queue_len() readers on audit_queue
If page allocation fails in trace_remote_alloc_buffer(), desc->nr_cpus
is not yet incremented for the current CPU. As a consequence, on error,
half-allocated rb_desc will not be freed in trace_remote_free_buffer().
Increment desc->nr_cpus as soon as the first allocation for the current
CPU has succeeded.
Link: https://patch.msgid.link/20260709160017.1729517-2-vdonnefort@google.com
Fixes: 96e43537af ("tracing: Introduce trace remotes")
Reported-by: Sashiko <sashiko-bot@kernel.org>
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
When switching a task's sched_class away from sched_ext, we get the
following sequence of events in __sched_setscheduler():
sched_change_begin()
switched_from_scx()
scx_disable_task(p)
ops.disable(p)
__setscheduler_params()
set_load_weight()
reweight_task_scx(p)
ops.set_weight(p)
p->sched_class = next_class;
sched_change_end()
...
Notably, ops.set_weight() is called _after_ ops.disable().
This violates the expected semantics of the callbacks, the expectation
being that ops.disable() can only be followed by ops.exit_task() or
ops.enable().
Skipping the weight adjustment for disabled tasks should be harmless
since the weight will be recalculated in scx_enable_task() if the task
ever rejoins SCX.
Fixes: 637b068282 ("sched: Fold sched_class::switch{ing,ed}_{to,from}() into the change pattern")
Cc: stable@vger.kernel.org # v6.19+
Signed-off-by: Kuba Piecuch <jpiecuch@google.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
map_range() reads rb->aux_pages[], rb->aux_nr_pages and rb->aux_pgoff via
perf_mmap_to_page() while holding only event->mmap_mutex. Those fields are
serialized by rb->aux_mutex, and mmap_mutex is per event.
Thus, two events sharing one rb via PERF_EVENT_IOC_SET_OUTPUT can race
rb_alloc_aux() with map_range(), leading to a page-UAF scenario as follows:
CPU 0 CPU 1
===== =====
rb_alloc_aux() map_range()
[1]: allocate rb->aux_pages[0]
[2]: rb->aux_nr_pages++
[3]: perf_mmap_to_page()
returns rb->aux_pages[0]
[4]: map it as VM_PFNMAP
[5]: rb->aux_pgoff = 1
munmap the page
[6]: free rb->aux_pages[0]
Pages mapped as VM_PFNMAP have no refcount protection, so CPU 1 holds a
mapping to a freed physical frame.
Fix this by taking rb->aux_mutex across the page walk in map_range().
Fixes: b709eb872e ("perf: map pages in advance")
Signed-off-by: Lee Jia Jie <jiajie.lee@starlabs.sg>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: stable@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
scx_alloc_and_add_sched() publishes @sch through ops->priv before allocating
the cgroup path. If that allocation fails, the unwind path clears ops->priv
and frees @sch immediately. scx_prog_sched() callers can dereference
ops->priv from RCU context the moment it is set, so freeing without a grace
period can use-after-free a concurrent kfunc caller.
Move the publication below the cgroup path allocation so that every failure
path after publication frees @sch through kobject_put(), whose release path
defers the freeing by a grace period.
Fixes: 105dcd005b ("sched_ext: Introduce scx_prog_sched()")
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Andrea Righi <arighi@nvidia.com>
scx_sub_enable_workfn() has several failure paths that only return an errno
(e.g. -ENOMEM from an allocation) and jump to err_disable without calling
scx_error(). scx_flush_disable_work() runs the disable, and thus ops.exit(),
only when an error has been recorded, so an errno-only failure leaves the
half-initialized sub-scheduler linked.
Record an error at the err_disable sink so every errno-only failure runs the
disable path.
Fixes: ebeca1f930 ("sched_ext: Introduce cgroup sub-sched support")
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Andrea Righi <arighi@nvidia.com>
set_next_task_scx() updates the tick dependency before __schedule()
updates rq->curr. When switching from a non-EXT task, such as idle, to
an EXT task with a finite slice, sched_update_tick_dependency() checks
the outgoing task and can allow the tick to remain stopped.
The dependency can also be lost without a slice-type transition. After a
finite-slice task leaves the CPU idle, the enqueue path can clear the
dependency against the idle rq->curr. SCX_RQ_CAN_STOP_TICK still records
a finite slice, so another finite task skips the transition block and
can run without the ticks needed to expire its slice.
The reverse mismatch can also happen when the last finite-slice EXT task
is dequeued: sub_nr_running() updates the dependency before rq->curr
changes, so the outgoing task state can keep the dependency set after
the CPU goes idle.
Fix this by unconditionally enabling the scheduler tick whenever a
finite-slice EXT task is selected on a nohz_full CPU. Moreover, when the
last runnable EXT task leaves, ignore the outgoing EXT slice state so
the generic scheduler can correctly re-evaluate and clear the tick
dependency.
Fixes: 22a920209a ("sched_ext: Implement tickless support")
Signed-off-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
The function calculates new_len as len << 1 for hex encoding. This
has two overflow risks: the shift itself can overflow when len is
large, and the result can be truncated when assigned to new_len
(declared as int) from the size_t calculation.
Fix by using check_shl_overflow() to catch shift overflow and
changing new_len and loop counter i to size_t to prevent truncation.
Cc: stable@vger.kernel.org
Fixes: 168b717395 ("AUDIT: Clean up logging of untrusted strings")
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Ricardo Robaina <rrobaina@redhat.com>
[PM: remove vertical whitspace noise]
Signed-off-by: Paul Moore <paul@paul-moore.com>
dispatch_to_local_dsq() can run from scx_bpf_dsq_move_to_local() while
ops.dispatch() has recorded the current rq. Moving a task to a local DSQ
may switch to the source or destination rq before synchronously invoking
ops.dequeue() through the following path:
SCX_CALL_OP(dispatch, rq)
ops.dispatch()
scx_bpf_dsq_move_to_local()
scx_flush_dispatch_buf()
finish_dispatch()
dispatch_to_local_dsq()
scx_dispatch_enqueue()
local_dsq_post_enq()
call_task_dequeue()
SCX_CALL_OP_TASK(dequeue, locked_rq, ...)
The nested callback saves the recorded rq and restores it on return. If
the rq tracking does not follow the lock switch, update_locked_rq() can
trigger the following lockdep assertion while restoring an rq which is
no longer held:
WARNING: kernel/sched/sched.h:1641 at call_task_dequeue+0x160/0x170
Call Trace:
scx_dispatch_enqueue+0x2b0/0x460
dispatch_to_local_dsq+0x138/0x230
scx_flush_dispatch_buf+0x1af/0x220
scx_bpf_dsq_move_to_local___v2+0xe2/0x1c0
bpf__sched_ext_ops_dispatch+0x4b/0xa7
do_pick_task_scx+0x3b6/0x910
__pick_next_task+0x105/0x1f0
__schedule+0x3e7/0x1980
Introduce switch_rq_lock() to update the tracking state together with
each rq lock handoff. Use it in dispatch_to_local_dsq(),
move_remote_task_to_local_dsq() and the in-balance paths of
scx_dsq_move(), ensuring that scx_locked_rq() consistently refers to the
rq whose lock is actually held throughout the lock dance.
Fixes: 7fb39e4eb4 ("sched_ext: Save and restore scx_locked_rq across SCX_CALL_OP")
Cc: stable@vger.kernel.org # 7.1+
Signed-off-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
user_event_mm_dup() walks the parent mm's enabler list locklessly under
rcu_read_lock() during fork() (from copy_process()); it does not take
event_mutex:
rcu_read_lock();
list_for_each_entry_rcu(enabler, &old_mm->enablers, mm_enablers_link)
enabler->event = user_event_get(orig->event);
user_event_enabler_destroy() removes an enabler from that list with
list_del_rcu() and then, without waiting for a grace period, drops the
enabler's user_event reference with user_event_put() and frees the enabler
with kfree(). A reader that loaded the enabler before the list_del_rcu()
can still be walking it, which leads to two use-after-frees:
- kfree(enabler) frees the enabler while that reader dereferences
enabler->event.
- user_event_put() may drop the last reference to the user_event, which
is then freed (via delayed_destroy_user_event() on a work queue), while
the same reader does user_event_get(orig->event) on it.
Both are reachable by an unprivileged task that can open user_events_data:
one multithreaded process that registers an enabler and then concurrently
unregisters it and calls fork() triggers the race. KASAN reports a
slab-use-after-free in user_event_mm_dup() during clone(), with a
"refcount_t: addition on 0" warning when the user_event is freed.
The enabler use-after-free was found first; the user_event one was reported
by XIAO WU, and the earlier enabler-only fix did not address it.
Defer both the user_event_put() and the kfree(enabler) to a work item
queued with queue_rcu_work(), so they run only after an RCU grace period,
once all readers walking the enabler list have finished. The put must run
in process context because user_event_put() takes event_mutex on the last
reference, so a work queue is used rather than call_rcu(). The now-unlocked
put lets the locked argument of user_event_enabler_destroy() be removed;
all callers are updated.
Fixes: 7235759084 ("tracing/user_events: Use remote writes for event enablement")
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260707165912.2560537-2-michael.bommarito@gmail.com
Reported-by: XIAO WU <xiaowu.417@qq.com>
Closes: https://lore.kernel.org/all/tencent_89647CE40DC452B891C65C94D1B271DE8E07@qq.com/
Suggested-by: Beau Belgrave <beaub@linux.microsoft.com>
Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Michael Bommarito <michael.bommarito@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Tracepoints require that RCU is watching. To prevent them from being used
in places that RCU is not watching, the trace_##event() macro always
calls rcu_is_watching() even when the event is not enabled and warns if
RCU is not watching. This is to make sure a warning is triggered even if
the tracepoint is never enabled (as it is only a bug when it is).
It was noticed that tracepoints could be hidden within
trace_#event#_enabled() calls, which are used to do extra work for the
tracepoint only if the tracepoint is enabled. But this also can hide the
fact that a tracepoint is placed in a location that can be called when RCU
is not watching.
Commit 9764e731ef ("tracepoint: Add lockdep rcu_is_watching() check to
trace_##name##_enabled()") added a check to the trace_##event##_enabled()
macro to make sure RCU is watching when it is called to make sure not to
hide the bug of a tracepoint being called when RCU is not watching.
There is one case in the irq_disable tracepoint where it is within a
trace_irq_disable_enabled() block, but it checks if RCU is watching, and
if it isn't, it makes a call to ct_irq_enter() that makes RCU watch again.
But because trace_irq_disable_enabled() now checks if RCU is watching and
will trigger if it isn't. This is a false warning as the code within
the block handles this case.
Add a new internal macro __trace_##event##_enabled() that doesn't check if
RCU is watching, and convert the irq_enable/disable tracepoints over to
it.
Link: https://patch.msgid.link/20260701132744.6a7fc68b@robin
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Closes: https://lore.kernel.org/all/CAMuHMdXud_RpWag_hFqa2ByBGRxg6KnxGL1ObCWZrpTsk3TfAw@mail.gmail.com/
Fixes: 9764e731ef ("tracepoint: Add lockdep rcu_is_watching() check to trace_##name##_enabled()")
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
String event fields are not necessarily NUL-terminated, so the filter
predicate functions (filter_pred_string(), filter_pred_strloc() and
filter_pred_strrelloc()) pass the field length to the regex match
callbacks, and the length-aware matchers honour it.
regex_match_glob() was the exception: it ignored the length and called
glob_match(), which scans the string until it hits a NUL byte. Some
string fields are not NUL-terminated. One example is the dynamic char
array of the xfs_* namespace tracepoints, which is copied without a
trailing NUL. For such a field, glob matching reads past the end of
the event field, causing a KASAN slab-out-of-bounds read in
glob_match(), reached via regex_match_glob() and filter_match_preds()
from the xfs_lookup tracepoint.
Add a length-bounded glob_match_len() and use it from regex_match_glob()
so glob matching always stops at the field boundary. The matching loop
is factored into a shared helper so glob_match() keeps its behaviour.
Fixes: 60f1d5e3ba ("ftrace: Support full glob matching")
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/da1aaf125fc3b63320b0c540fd6afa7c3d5b4f1a.1782836943.git.hhhuang@smu.edu.sg
Reported-by: Yuan Tan <yuantan098@gmail.com>
Reported-by: Yifan Wu <yifanwucs@gmail.com>
Reported-by: Juefei Pu <tomapufckgml@gmail.com>
Reported-by: Zhengchuan Liang <zcliangcn@gmail.com>
Reported-by: Xin Liu <bird@lzu.edu.cn>
Assisted-by: Codex:GPT-5.4
Signed-off-by: Huihui Huang <hhhuang@smu.edu.sg>
Signed-off-by: Ren Wei <n05ec@lzu.edu.cn>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
func_set_flag() dereferences tr->current_trace_flags before verifying
that the current tracer is actually the function tracer. When the active
tracer has been switched away from "function" (e.g., to "wakeup_rt"),
tr->current_trace_flags can be NULL, leading to a NULL pointer
dereference and kernel crash.
The call chain that triggers this is:
trace_options_write()
-> __set_tracer_option()
-> trace->set_flag() /* func_set_flag */
In func_set_flag(), the first operation is:
if (!!set == !!(tr->current_trace_flags->val & bit))
This dereferences tr->current_trace_flags unconditionally. The safety
check that guards against a non-function tracer:
if (tr->current_trace != &function_trace)
return 0;
is placed *after* the dereference, which is too late.
This was observed with the following crash dump:
BUG: unable to handle page fault at 0000000000000000
RIP: func_set_flag+0xd
Call Trace:
__set_tracer_option+0x27
trace_options_write+0x75
vfs_write+0x12a
ksys_write+0x66
do_syscall_64+0x5b
RIP: ffffffff914c973d RSP: ff67ec88b01dfdf0 RFLAGS: 00010202
RAX: 0000000000000000 RBX: ff3a826e80354580 RCX: 0000000000000001
RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffffffff93918080
The disassembly confirms the fault:
func_set_flag+0: mov 0x1f08(%rdi), %rax ; RAX = tr->current_trace_flags = NULL
func_set_flag+13: mov (%rax), %eax ; page fault: dereference NULL
At the time of the crash:
tr->current_trace_flags = 0x0 (NULL)
tr->current_trace = wakeup_rt_tracer (not function_trace)
The scenario is that a process opens a function tracer option file (such
as "func_stack_trace"), then the current tracer is switched to another
tracer (e.g., "wakeup_rt"), which sets current_trace_flags to NULL. When
the process subsequently writes to the option file, func_set_flag() is
invoked and crashes on the NULL dereference.
Fix this by moving the current_trace check before the
current_trace_flags dereference, so that func_set_flag() returns early
when the function tracer is not active.
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260624061715.1445655-1-xiangzao@linux.alibaba.com
Fixes: 76680d0d28 ("tracing: Have function tracer define options per instance")
Signed-off-by: Yuanhe Shu <xiangzao@linux.alibaba.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Commit 8928e4a3be ("ring-buffer: Show persistent buffer dropped events
in trace_pipe file") split the "commit" variable in
ring_buffer_read_page() into "commit" (raw) and "size" (masked page
size), but the inner copy loop's terminator was changed to compare rpos
against "event_size" instead of "size".
rpos is the cumulative read offset within the page; event_size is the
length of the single event just copied. The loop thus breaks after the
first event, so only one event is copied per call. This regresses the
per-event memcpy path (partial reads, the active commit page, and
mapped/remote buffers) used by splice/trace_pipe_raw and mmap consumers
into a one-event-at-a-time read.
Compare rpos against the page size as the original code did.
Link: https://patch.msgid.link/20260616175538.111628-1-devnexen@gmail.com
Fixes: 8928e4a3be ("ring-buffer: Show persistent buffer dropped events in trace_pipe file")
Signed-off-by: David Carlier <devnexen@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
In tracing_set_tracer(), the assignment 'ret = 0' following the
__tracing_resize_ring_buffer() error check is a dead store. After
this point, all subsequent code paths either return with a constant
value (-EINVAL, 0, -EBUSY) or reassign ret before reading it
(tracing_arm_snapshot_locked, tracer_init).
Remove the unnecessary assignment.
No functional change.
Link: https://patch.msgid.link/6a2a37c4.f0a9eb5a.2fc603.7724@mx.google.com
Signed-off-by: Wayen.Yan <win847@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
