linux.git/kernel/trace, branch v7.2-rc5 Linux kernel source tree Merge tag 'trace-v7.2-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace 2026-07-26T16:15:59+00:00 Linus Torvalds torvalds@linux-foundation.org 2026-07-26T16:15:59+00:00 864be1277d3e6bfb1201def9a32d46f542d8debd Pull tracing fixes from Steven Rostedt: - Move rb_desc->nr_page_va before updating dynamic array The rb_descr->page_va is a dynamic array counted by nr_page_va. But the updating of the page_va[] is done before the nr_page_va is incremented causing a build with CONFIG_UBSAN_BOUNDS to flag it as an overflow. Move the increment of the counted by value before the array element is updated. - Propagate errors from remote event bulk updates The return value of trace_remote_enable_event() was not being checked by remote_events_dir_enable_write() where it would silently fail. Have it check the return value and propagate that back up to user space. - Fix resource leak on mmiotrace trace_pipe close The mmiotrace tracer was created in 2008 before the trace_pipe had a close callback to allow tracers to do clean up from trace_pipe open. The trace_pipe close cleanup callback was added in 2009 but the mmiotrace tracer was not updated. It had a hack to do the cleanup in the read call, where it may leak if user space did not read the entire buffer. Add a callback to mmiotrace trace_pipe close do to the cleanup properly. - Fix a possible NULL pointer dereference in the mmiotrace tracer If the mmio_pipe_open() fails to find a PCI device, it will set the hiter->dev pointer to NULL. The read function will blindly dereference that pointer. Fix the read call to check to see if that pointer is populated before dereferencing it. - Fix union collision of module and refcnt for dynamic events In 'struct trace_event_call', the 'module' pointer and the 'refcnt' atomic variable share the same memory space in a union. The filter on module logic only checked if the 'module' was set to determine if the event belonged to the module. As dynamic events are always builtin, it doesn't need the 'module' field of the structure and used a refcount. But the module filtering logic would then mistaken these dynamic events as a module and call module_name(event->module) on it. Add a check to see if the event is a dynamic event and if so, do not check it for being part of the given module. - Reset the top level buffer in selftests before running instances The ftracetest selftest initializes each instance before executing the tests. But it does not reset the top level buffer. Dynamic events are only added and removed by the top level so any left over dynamic events will not be removed by the reset in the instances. Left over dynamic events can cause the tests to incorrectly fail. Reset the top level buffer before running the instances. - Make the context_switch counter 64 bit The code to read user space for a system call trace event or for a trace_marker will disable migration, enable preemption, read user space into a per CPU buffer, disable preemption and enable migration again. It checks if the per CPU context switch counter to see if it changed, and if it did not, it would know that the per CPU buffer was not touched by another task. But the save counter was 32 bit and it would compare it to the 64 bit context_switch variable. A long running system could have the context_switch variable greater that 1<<32 in which case the compare will always fail. The compare will promote the 32 bit int saved value to 64 bit and compare it to the full 64 bit counter. Since the top 32 bits of the saved value was zero, it would never match. - Fix a use-after-free of the event_enable trigger The event_enable trigger allows for enabling one event when another event is triggered. When the trigger is removed, it must go through a synchronization phase to make sure it is not triggered again. The trigger itself is delayed by the "bulk delay" logic that was recently added. But the code that frees the event_enable data used to rely on the trigger code to do the synchronization. Now that the code uses the call RCU functions (and a workqueue), that delay no longer is there. Add a callback private_data_free() function that allows triggers to clean up data after the synchronization phase has completed. - Move the module_ref counter into the delay callback Since an event of the event_enable trigger can enable an event for a module, it ups the module ref count for that event's module. This prevents the event from trying to enable an event that no longer exists and cause a use-after-free bug. The ref counter was set back down when the trigger was removed but not after thy synchronization phase. This could lead to the module data being accessed after module was unloaded. Move the module ref decrement into the private_data_free() callback of the event_enable trigger. - Add mutex to protect parser in ftrace filtering The set_ftrace_filter file uses a parsing descriptor that is allocated at open and modified by writes. If multiple threads were to write to the descriptor at the same time, it can corrupt the parser. Add a mutex around the modifications of the parser descriptor. - Fix possible corruption in perf syscall tracing The perf system call trace events can now read user space. To do so, the reads of user space enable preemption and disables it again. During this time that preemption is enabled, the task can migrate. The perf event list head is assigned via a per CPU pointer. It is done before the user space part is called. If the user space reading migrates the task to another CPU, then the head pointer is no longer valid. Re-assign the head pointer after the reading of user space to keep it using the correct data. * tag 'trace-v7.2-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: tracing: perf: Fix stale head for perf syscall tracing ftrace: Add global mutex to serialize trace_parser access tracing: Delay module ref count for "enable_event" trigger tracing: Fix use-after-free freeing trigger private data tracing: Fix context switch counter truncation selftests/ftrace: Reset triggers at top level before instance loop tracing: Fix union collision of module and refcnt for dynamic events tracing: Fix mmiotrace possible NULL dereferencing of hiter->dev tracing: Fix resource leak on mmiotrace trace_pipe close tracing: Propagate errors from remote event bulk updates tracing/remotes: Fix page_va[] access before counter update in trace_remote_alloc_buffer() 
Pull tracing fixes from Steven Rostedt:

 - Move rb_desc->nr_page_va before updating dynamic array

   The rb_descr->page_va is a dynamic array counted by nr_page_va. But
   the updating of the page_va[] is done before the nr_page_va is
   incremented causing a build with CONFIG_UBSAN_BOUNDS to flag it as an
   overflow.

   Move the increment of the counted by value before the array element
   is updated.

 - Propagate errors from remote event bulk updates

   The return value of trace_remote_enable_event() was not being checked
   by remote_events_dir_enable_write() where it would silently fail.
   Have it check the return value and propagate that back up to user
   space.

 - Fix resource leak on mmiotrace trace_pipe close

   The mmiotrace tracer was created in 2008 before the trace_pipe had a
   close callback to allow tracers to do clean up from trace_pipe open.
   The trace_pipe close cleanup callback was added in 2009 but the
   mmiotrace tracer was not updated. It had a hack to do the cleanup in
   the read call, where it may leak if user space did not read the
   entire buffer.

   Add a callback to mmiotrace trace_pipe close do to the cleanup
   properly.

 - Fix a possible NULL pointer dereference in the mmiotrace tracer

   If the mmio_pipe_open() fails to find a PCI device, it will set the
   hiter->dev pointer to NULL. The read function will blindly
   dereference that pointer. Fix the read call to check to see if that
   pointer is populated before dereferencing it.

 - Fix union collision of module and refcnt for dynamic events

   In 'struct trace_event_call', the 'module' pointer and the 'refcnt'
   atomic variable share the same memory space in a union. The filter on
   module logic only checked if the 'module' was set to determine if the
   event belonged to the module. As dynamic events are always builtin,
   it doesn't need the 'module' field of the structure and used a
   refcount. But the module filtering logic would then mistaken these
   dynamic events as a module and call module_name(event->module) on it.

   Add a check to see if the event is a dynamic event and if so, do not
   check it for being part of the given module.

 - Reset the top level buffer in selftests before running instances

   The ftracetest selftest initializes each instance before executing
   the tests. But it does not reset the top level buffer. Dynamic events
   are only added and removed by the top level so any left over dynamic
   events will not be removed by the reset in the instances.

   Left over dynamic events can cause the tests to incorrectly fail.
   Reset the top level buffer before running the instances.

 - Make the context_switch counter 64 bit

   The code to read user space for a system call trace event or for a
   trace_marker will disable migration, enable preemption, read user
   space into a per CPU buffer, disable preemption and enable migration
   again. It checks if the per CPU context switch counter to see if it
   changed, and if it did not, it would know that the per CPU buffer was
   not touched by another task.

   But the save counter was 32 bit and it would compare it to the 64 bit
   context_switch variable. A long running system could have the
   context_switch variable greater that 1<<32 in which case the compare
   will always fail. The compare will promote the 32 bit int saved value
   to 64 bit and compare it to the full 64 bit counter. Since the top 32
   bits of the saved value was zero, it would never match.

 - Fix a use-after-free of the event_enable trigger

   The event_enable trigger allows for enabling one event when another
   event is triggered. When the trigger is removed, it must go through a
   synchronization phase to make sure it is not triggered again. The
   trigger itself is delayed by the "bulk delay" logic that was recently
   added. But the code that frees the event_enable data used to rely on
   the trigger code to do the synchronization. Now that the code uses
   the call RCU functions (and a workqueue), that delay no longer is
   there.

   Add a callback private_data_free() function that allows triggers to
   clean up data after the synchronization phase has completed.

 - Move the module_ref counter into the delay callback

   Since an event of the event_enable trigger can enable an event for a
   module, it ups the module ref count for that event's module. This
   prevents the event from trying to enable an event that no longer
   exists and cause a use-after-free bug.

   The ref counter was set back down when the trigger was removed but
   not after thy synchronization phase. This could lead to the module
   data being accessed after module was unloaded.

   Move the module ref decrement into the private_data_free() callback
   of the event_enable trigger.

 - Add mutex to protect parser in ftrace filtering

   The set_ftrace_filter file uses a parsing descriptor that is
   allocated at open and modified by writes. If multiple threads were to
   write to the descriptor at the same time, it can corrupt the parser.

   Add a mutex around the modifications of the parser descriptor.

 - Fix possible corruption in perf syscall tracing

   The perf system call trace events can now read user space. To do so,
   the reads of user space enable preemption and disables it again.
   During this time that preemption is enabled, the task can migrate.
   The perf event list head is assigned via a per CPU pointer. It is
   done before the user space part is called. If the user space reading
   migrates the task to another CPU, then the head pointer is no longer
   valid.

   Re-assign the head pointer after the reading of user space to keep it
   using the correct data.

* tag 'trace-v7.2-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing: perf: Fix stale head for perf syscall tracing
  ftrace: Add global mutex to serialize trace_parser access
  tracing: Delay module ref count for "enable_event" trigger
  tracing: Fix use-after-free freeing trigger private data
  tracing: Fix context switch counter truncation
  selftests/ftrace: Reset triggers at top level before instance loop
  tracing: Fix union collision of module and refcnt for dynamic events
  tracing: Fix mmiotrace possible NULL dereferencing of hiter->dev
  tracing: Fix resource leak on mmiotrace trace_pipe close
  tracing: Propagate errors from remote event bulk updates
  tracing/remotes: Fix page_va[] access before counter update in trace_remote_alloc_buffer()
tracing: perf: Fix stale head for perf syscall tracing 2026-07-25T02:57:56+00:00 Steven Rostedt rostedt@goodmis.org 2026-07-24T23:32:10+00:00 2c2b322acdcc78575b8d6afa64a085cf92e03c12 The code that can read the user space parameters of a system call may enable preemption and migrate. The head of the per CPU perf events list may be pointing to the wrong CPU event if the code migrates the task. Reassign the head pointer if the system call event called the code that may have caused a migration. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260724193210.03fae1d6@gandalf.local.home Reported-by: Sashiko <> Link: https://sashiko.dev/#/patchset/20260717173252.3431565-1-usama.arif%40linux.dev Fixes: edca33a56297d ("tracing: Fix failure to read user space from system call trace events") Signed-off-by: Steven Rostedt <rostedt@goodmis.org> 
The code that can read the user space parameters of a system call may
enable preemption and migrate. The head of the per CPU perf events list
may be pointing to the wrong CPU event if the code migrates the task.

Reassign the head pointer if the system call event called the code that
may have caused a migration.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260724193210.03fae1d6@gandalf.local.home
Reported-by: Sashiko <>
Link: https://sashiko.dev/#/patchset/20260717173252.3431565-1-usama.arif%40linux.dev
Fixes: edca33a56297d ("tracing: Fix failure to read user space from system call trace events")
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
ftrace: Add global mutex to serialize trace_parser access 2026-07-25T02:56:43+00:00 Tengda Wu wutengda@huaweicloud.com 2026-07-25T02:47:21+00:00 7720b63bcef3f54c7fe288774b720a227d54a306 In ftrace, the trace_parser structure is allocated and initialized when a trace file is opened, and is subsequently used across write and release handlers to parse user input. The affected handler paths and their specific functions are: - Open paths: ftrace_regex_open(), ftrace_graph_open() - Write paths: ftrace_regex_write(), ftrace_graph_write() - Release paths: ftrace_regex_release(), ftrace_graph_release() If userspace opens a trace file descriptor and shares it across multiple threads, concurrent write calls will race on the parser's internal state, specifically the 'idx', 'cont', and 'buffer' fields, leading to corrupted input or undefined behavior. Fix this by adding a global mutex, parser_lock, to serialize all access to trace_parser across write and release paths, preventing concurrent corruption of parser state. Fixes: e704eff3ff51 ("ftrace: Have set_graph_function handle multiple functions in one write") Fixes: 689fd8b65d66 ("tracing: trace parser support for function and graph") Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260725024721.1983675-1-wutengda@huaweicloud.com Signed-off-by: Tengda Wu <wutengda@huaweicloud.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> 
In ftrace, the trace_parser structure is allocated and initialized when
a trace file is opened, and is subsequently used across write and release
handlers to parse user input.

The affected handler paths and their specific functions are:
  - Open paths: ftrace_regex_open(), ftrace_graph_open()
  - Write paths: ftrace_regex_write(), ftrace_graph_write()
  - Release paths: ftrace_regex_release(), ftrace_graph_release()

If userspace opens a trace file descriptor and shares it across multiple
threads, concurrent write calls will race on the parser's internal state,
specifically the 'idx', 'cont', and 'buffer' fields, leading to corrupted
input or undefined behavior.

Fix this by adding a global mutex, parser_lock, to serialize all access
to trace_parser across write and release paths, preventing concurrent
corruption of parser state.

Fixes: e704eff3ff51 ("ftrace: Have set_graph_function handle multiple functions in one write")
Fixes: 689fd8b65d66 ("tracing: trace parser support for function and graph")
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260725024721.1983675-1-wutengda@huaweicloud.com
Signed-off-by: Tengda Wu <wutengda@huaweicloud.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
tracing: Delay module ref count for "enable_event" trigger 2026-07-24T22:49:51+00:00 Steven Rostedt rostedt@goodmis.org 2026-07-24T17:24:15+00:00 e091351b38818ef620d27f44f4bfd625f13afbff Triggers are now delayed from freeing, but can still be triggered until after the RCU grace period has ended. The freeing of the enable_event data is put into the private_data_free() callback, but the put of the module refcount is done immediately. It is possible that if a module is removed that has an event that would enable (or disable) it is still active, it can read the data of the module after it is removed causing a use-after-free bug. Move the trace_event_put_ref() that releases the module into the delayed callback so that the module can not be removed until any reference to its events are finished. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260724132415.1b5005db@gandalf.local.home Reported-by: Sashiko <sashiko-bot@kernel.org> Link: https://sashiko.dev/#/patchset/20260724030523.19081-1-devnexen%40gmail.com Fixes: 61d445af0a7c ("tracing: Add bulk garbage collection of freeing event_trigger_data") Signed-off-by: Steven Rostedt <rostedt@goodmis.org> 
Triggers are now delayed from freeing, but can still be triggered until
after the RCU grace period has ended. The freeing of the enable_event data
is put into the private_data_free() callback, but the put of the module
refcount is done immediately.

It is possible that if a module is removed that has an event that would
enable (or disable) it is still active, it can read the data of the module
after it is removed causing a use-after-free bug.

Move the trace_event_put_ref() that releases the module into the delayed
callback so that the module can not be removed until any reference to its
events are finished.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260724132415.1b5005db@gandalf.local.home
Reported-by: Sashiko <sashiko-bot@kernel.org>
Link: https://sashiko.dev/#/patchset/20260724030523.19081-1-devnexen%40gmail.com
Fixes: 61d445af0a7c ("tracing: Add bulk garbage collection of freeing event_trigger_data")
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
tracing: Fix use-after-free freeing trigger private data 2026-07-24T22:49:51+00:00 David Carlier devnexen@gmail.com 2026-07-24T03:05:17+00:00 79097812153b826fc156a2930ec8a90ed9edf4a2 Commit 61d445af0a7c ("tracing: Add bulk garbage collection of freeing event_trigger_data") moved the kfree() of event_trigger_data to a kthread that runs tracepoint_synchronize_unregister() before freeing. That removed the synchronization the trigger .free callbacks used to get implicitly and inline from trigger_data_free(). event_hist_trigger_free(), event_hist_trigger_named_free() and event_enable_trigger_free() free their satellite data (hist_data, cmd_ops, enable_data) right after trigger_data_free() returns. With the synchronization now deferred to the kthread, a concurrent tracepoint handler can still reach that data through the list_del_rcu()'d trigger, causing a use-after-free. The histogram teardown must stay synchronous: remove_hist_vars() and unregister_field_var_hists() have to detach a synthetic event from the histogram before the trigger-removal write returns, otherwise a following command races in and the synthetic-event removal fails with -EBUSY, as the trigger-synthetic-eprobe.tc selftest catches. Make those callbacks wait with the correct barrier - tracepoint_synchronize_unregister(), matching the free kthread - before freeing. The enable trigger has no such synchronous requirement, and a blocking synchronize there would re-serialize the path that commit deliberately deferred. Give it an optional private_data_free() callback that the free kthread runs after its grace period, and free enable_data from there. Link: https://patch.msgid.link/20260724030523.19081-1-devnexen@gmail.com Suggested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Suggested-by: Steven Rostedt <rostedt@goodmis.org> Fixes: 61d445af0a7c ("tracing: Add bulk garbage collection of freeing event_trigger_data") Signed-off-by: David Carlier <devnexen@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> 
Commit 61d445af0a7c ("tracing: Add bulk garbage collection of freeing
event_trigger_data") moved the kfree() of event_trigger_data to a kthread
that runs tracepoint_synchronize_unregister() before freeing. That removed
the synchronization the trigger .free callbacks used to get implicitly and
inline from trigger_data_free().

event_hist_trigger_free(), event_hist_trigger_named_free() and
event_enable_trigger_free() free their satellite data (hist_data, cmd_ops,
enable_data) right after trigger_data_free() returns. With the
synchronization now deferred to the kthread, a concurrent tracepoint
handler can still reach that data through the list_del_rcu()'d trigger,
causing a use-after-free.

The histogram teardown must stay synchronous: remove_hist_vars() and
unregister_field_var_hists() have to detach a synthetic event from the
histogram before the trigger-removal write returns, otherwise a following
command races in and the synthetic-event removal fails with -EBUSY, as the
trigger-synthetic-eprobe.tc selftest catches. Make those callbacks wait
with the correct barrier - tracepoint_synchronize_unregister(), matching
the free kthread - before freeing.

The enable trigger has no such synchronous requirement, and a blocking
synchronize there would re-serialize the path that commit deliberately
deferred. Give it an optional private_data_free() callback that the free
kthread runs after its grace period, and free enable_data from there.

Link: https://patch.msgid.link/20260724030523.19081-1-devnexen@gmail.com
Suggested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Fixes: 61d445af0a7c ("tracing: Add bulk garbage collection of freeing event_trigger_data")
Signed-off-by: David Carlier <devnexen@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
tracing: Fix context switch counter truncation 2026-07-24T17:43:18+00:00 Usama Arif usama.arif@linux.dev 2026-07-17T17:32:52+00:00 8f76afb9b114bee1c1251e0e52553e9dc7c59f20 trace_user_fault_read() samples nr_context_switches_cpu() before enabling preemption and retries the user copy if the counter changes. The helper returns unsigned long long because rq->nr_switches is u64, but the saved value is unsigned int. Once a CPU has performed 2^32 context switches, assigning the counter to cnt discards its upper bits. The comparison after the copy promotes cnt back to unsigned long long, but the lost bits remain zero, so it reports a change even when the task was never scheduled out. Every retry then fails the same way until the 100-try guard warns and the user copy is abandoned. This affects long-running systems and workloads with high context-switch rates. A CPU switching 1,000 times per second takes about 50 days. Store the sampled count in unsigned long long so the full value is preserved. Cc: stable@vger.kernel.org Fixes: 64cf7d058a00 ("tracing: Have trace_marker use per-cpu data to read user space") Link: https://patch.msgid.link/20260717173252.3431565-1-usama.arif@linux.dev Reported-by: Breno Leitao <leitao@debian.org> Signed-off-by: Usama Arif <usama.arif@linux.dev> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Reviewed-by: Breno Leitao <leitao@debian.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> 
trace_user_fault_read() samples nr_context_switches_cpu() before enabling
preemption and retries the user copy if the counter changes. The helper
returns unsigned long long because rq->nr_switches is u64, but the saved
value is unsigned int.

Once a CPU has performed 2^32 context switches, assigning the counter to
cnt discards its upper bits. The comparison after the copy promotes cnt
back to unsigned long long, but the lost bits remain zero, so it reports a
change even when the task was never scheduled out. Every retry then fails
the same way until the 100-try guard warns and the user copy is abandoned.

This affects long-running systems and workloads with high context-switch
rates. A CPU switching 1,000 times per second takes about 50 days.

Store the sampled count in unsigned long long so the full value is
preserved.

Cc: stable@vger.kernel.org
Fixes: 64cf7d058a00 ("tracing: Have trace_marker use per-cpu data to read user space")
Link: https://patch.msgid.link/20260717173252.3431565-1-usama.arif@linux.dev
Reported-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Usama Arif <usama.arif@linux.dev>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
tracing: Fix union collision of module and refcnt for dynamic events 2026-07-24T17:43:17+00:00 Masami Hiramatsu (Google) mhiramat@kernel.org 2026-07-17T02:51:49+00:00 b4eb07bde606c2096b24252be589e735eff6d413 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: 4c86bc531e60 ("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> 
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: 4c86bc531e60 ("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>
tracing: Fix mmiotrace possible NULL dereferencing of hiter->dev 2026-07-24T17:43:09+00:00 Steven Rostedt rostedt@goodmis.org 2026-07-22T01:11:43+00:00 144f29e85702234b23d2a62abf723e6a17eb5427 If the mmio_pipe_open() fails to find a PCI device, the hiter->dev will be assigned to NULL. The mmiotrace read() function dereferences the hiter->dev if hiter exists. Change the test of the read to not only check hiter being NULL, but also the hiter->dev before dereferencing it. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260721211143.36dbd559@gandalf.local.home Fixes: f984b51e0779 ("ftrace: add mmiotrace plugin") Reported-by: Sashiko <sashiko-bot@kernel.org> Link: https://sashiko.dev/#/patchset/20260715143604.14481-1-gaikwad.dcg%40gmail.com Signed-off-by: Steven Rostedt <rostedt@goodmis.org> 
If the mmio_pipe_open() fails to find a PCI device, the hiter->dev
will be assigned to NULL. The mmiotrace read() function dereferences the
hiter->dev if hiter exists.

Change the test of the read to not only check hiter being NULL, but also
the hiter->dev before dereferencing it.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260721211143.36dbd559@gandalf.local.home
Fixes: f984b51e0779 ("ftrace: add mmiotrace plugin")
Reported-by: Sashiko <sashiko-bot@kernel.org>
Link: https://sashiko.dev/#/patchset/20260715143604.14481-1-gaikwad.dcg%40gmail.com
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
tracing: Fix resource leak on mmiotrace trace_pipe close 2026-07-23T16:30:07+00:00 deepakraog gaikwad.dcg@gmail.com 2026-07-15T14:36:04+00:00 c1d87e724ae55e781b7cc7ccafb34d9e668582b2 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: c521efd1700a8 ("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> 
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: c521efd1700a8 ("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>
tracing: Propagate errors from remote event bulk updates 2026-07-23T16:30:07+00:00 Jackie Liu liuyun01@kylinos.cn 2026-07-15T07:44:55+00:00 655111f878a455f724e20122929cf2afa52b76e4 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: 775cb093bc50 ("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> 
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: 775cb093bc50 ("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>