7264 Commits
Author SHA1 Message Date
Linus Torvalds 2aa6a5e889 Merge tag 'trace-v7.2-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing fixes from Steven Rostedt:

 - Reset dropped_count in mmio_reset_data()

   When mmio_reset_data() is called, it does not reset the dropped_count
   so that subsequent runs will have incorrect reporting.

 - Add NULL check for mmio_trace_array in logging functions

   The functions __trace_mmiotrace_rw() and __trace_mmiotrace_map() may
   have the 'tr' variable passed to it as NULL. But they both
   dereference it without checking if it is NULL first.

 - Check return value of __register_event() in trace_module_add_events()

   If __register_event() fails, the __add_event_to_tracers() call after
   it will create a file for it. If the module fails to load and its
   memory is freed, the file will still point to it and it will not be
   removed as the registering of the event did not complete.

   Only call __add_event_to_tracers() if the __register_event() was
   successful.

 - Fix false positive match in regex_match_full()

   The regex full matching uses a strncmp() to test against the match
   string and the value. It should not match if value is a prefix of the
   string to match. Check to make sure the length of the strings match
   before comparing.

 - Fix reader page read offset for remote buffers

   A page swapped in by __rb_get_reader_page_from_remote() retains its
   stale read offset, causing subsequent reads to skip events or read
   past valid data.

 - Fix memory leak of subbuf_ids in rb_allocate_cpu_buffer()

   Remote buffers allocate a subbuf_ids array. If the allocator function
   fails after it is allocated, it does not free it, resulting in a
   memory leak.

* tag 'trace-v7.2-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Fix subbuf_ids memory leak in rb_allocate_cpu_buffer() error path
  ring-buffer: Fix reader page read offset for remote buffers
  tracing/filters: Fix false positive match in regex_match_full()
  tracing: Check return value of __register_event() in trace_module_add_events()
  tracing/mmiotrace: Add NULL check for mmio_trace_array in logging functions
  tracing/mmiotrace: Reset dropped_count in mmio_reset_data()
2026-07-31 20:24:11 -07:00
Masami Hiramatsu (Google)andSteven Rostedt 260b20d9b7 ring-buffer: Fix subbuf_ids memory leak in rb_allocate_cpu_buffer() error path
In rb_allocate_cpu_buffer(), cpu_buffer->subbuf_ids is allocated using
kcalloc() when buffer->remote is non-NULL. If a subsequent page allocation
fails (e.g., ring_buffer_desc_page() returns NULL or rb_allocate_pages()
fails), execution jumps to fail_free_reader.

While __free(kfree) automatically frees the outer cpu_buffer structure
at scope exit, kfree(cpu_buffer) does not recursively free nested heap
pointers such as cpu_buffer->subbuf_ids, resulting in a memory leak.

Fix this by explicitly freeing cpu_buffer->subbuf_ids in the
fail_free_reader error unwinding path when cpu_buffer->remote is set.

Link: https://patch.msgid.link/178550740672.380917.6067449683620196150.stgit@devnote2
Fixes: 2e67fabd8b ("ring-buffer: Introduce ring-buffer remotes")
Assisted-by: Antigravity:gemini-3.6-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-31 19:48:27 -04:00
Vincent DonnefortandSteven Rostedt 78cd56c2a9 ring-buffer: Fix reader page read offset for remote buffers
A page swapped in by __rb_get_reader_page_from_remote() retains its
stale read offset, causing subsequent reads to skip events or read
past valid data. Fix it.

Link: https://patch.msgid.link/20260729133609.4022734-1-vdonnefort@google.com
Fixes: fbd1743ecb ("ring-buffer: Add non-consuming read for ring-buffer remotes")
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Reviewed-by: Keir Fraser <keirf@google.com>
Tested-by: Keir Fraser <keirf@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-29 19:41:14 -04:00
Masami Hiramatsu (Google)andSteven Rostedt c22c7b735f tracing/filters: Fix false positive match in regex_match_full()
regex_match_full() calls strncmp(str, r->pattern, len) where len is the
target field buffer size. When len is smaller than r->len (the filter
pattern length), strncmp() checks only len bytes of r->pattern against
str. If those len bytes match, strncmp() returns 0, resulting in a
false-positive match where a shorter string in a fixed-size field
matches a longer filter pattern.

For example, a 4-byte static string field containing "abcd" matched the
filter pattern "abcdefgh" because strncmp("abcd", "abcdefgh", 4)
returned 0. In this case, @len does NOT include '\0' because it is
fixed-size array.

Fix this by returning 0 (no match) early when len < r->len.

Fixes: 1889d20922 ("tracing/filters: Provide basic regex support")
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/178528488779.124250.5571741156199253769.stgit@devnote2
Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-29 14:32:11 -04:00
Masami Hiramatsu (Google)andSteven Rostedt ac8719969e tracing: Check return value of __register_event() in trace_module_add_events()
trace_module_add_events() ignores the return value of __register_event()
and unconditionally calls __add_event_to_tracers() for each event.

If __register_event() fails (for example, if event_init() fails), the
trace_event_call is not added to ftrace_events list, but
__add_event_to_tracers() still creates a trace_event_file pointing to it.
If module loading subsequently fails and module memory is freed, tracing
state retains a stale trace_event_call pointer in trace_event_file,
leading to a use-after-free when tracefs or tracing subsystem operations
are later executed.

Fix this by checking the return value of __register_event() and only
calling __add_event_to_tracers() if event registration succeeded.

Fixes: ae63b31e4d ("tracing: Separate out trace events from global variables")
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/178528487878.124250.14170824576025743236.stgit@devnote2
Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-29 14:32:11 -04:00
Masami Hiramatsu (Google)andSteven Rostedt 12b80cdbc5 tracing/mmiotrace: Add NULL check for mmio_trace_array in logging functions
mmio_trace_rw() and mmio_trace_mapping() retrieve mmio_trace_array into
tr and pass it to __trace_mmiotrace_rw() and __trace_mmiotrace_map().
If these functions are invoked while mmio_trace_array is NULL (e.g. before
initialization or after disabled), accessing tr->array_buffer.buffer will
result in a NULL pointer dereference crash.

Fix this by adding an explicit NULL check for tr at the beginning of
__trace_mmiotrace_rw() and __trace_mmiotrace_map().

Link: https://patch.msgid.link/178524300062.56416.8362487250709962380.stgit@devnote2
Fixes: f984b51e07 ("ftrace: add mmiotrace plugin")
Assisted-by: Antigravity:gemini-3.6-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-29 14:27:55 -04:00
Masami Hiramatsu (Google)andSteven Rostedt c786d2bdf1 tracing/mmiotrace: Reset dropped_count in mmio_reset_data()
mmio_reset_data() is called during tracer initialization, reset, and
start. While it resets overrun_detected and prev_overruns, it neglects
to reset dropped_count. Consequently, dropped event counts from prior
tracing sessions persist in dropped_count and corrupt overrun reports
in subsequent runs.

Fix this by explicitly calling atomic_set(&dropped_count, 0) in
mmio_reset_data().

Link: https://patch.msgid.link/178524299122.56416.16277704230639425172.stgit@devnote2
Fixes: 173ed24ee2 ("mmiotrace: count events lost due to not recording")
Assisted-by: Antigravity:gemini-3.6-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-29 14:27:55 -04:00
Masami Hiramatsu (Google) 8cf2f40ceb fprobe: Fix module reference count leak on error in register_fprobe()
In register_fprobe(), get_ips_from_filter() resolves target function
addresses and increments module reference counts via try_module_get() for
symbols in kernel modules. If get_ips_from_filter() fails on the second
pass and returns an error, register_fprobe() returned directly without
releasing module references acquired up to that point.

Fix this by ensuring the cleanup loop executing module_put() runs even when
get_ips_from_filter() returns a negative error.

Link: https://lore.kernel.org/all/178528125360.101985.4144133640239273153.stgit@devnote2/

Fixes: d24fa977ee ("tracing: fprobe: Fix to lock module while registering fprobe")
Assisted-by: Antigravity:gemini-3.6-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2026-07-29 22:50:02 +09:00
Raushan PatelandMasami Hiramatsu (Google) aca0cd1bf1 tracing/fprobe: Roll back on enable_trace_fprobe() failure
enable_trace_fprobe() sets the file link or the TP_FLAG_PROFILE flag and
then registers each trace_fprobe in the probe list. If
__register_trace_fprobe() fails partway through, the function returns
immediately without unregistering the trace_fprobes it already registered
or undoing the file link / flag it set, leaving the event half-enabled and
leaking the registered fprobe(s).

enable_trace_kprobe() already handles this with a rollback path. Do the
same for fprobe: on failure, unregister all probes and clear the file link
or profile flag.

Link: https://lore.kernel.org/all/20260724064208.480030-1-raushan.jhon@gmail.com/

Fixes: 334e5519c3 ("tracing/probes: Add fprobe events for tracing function entry and exit.")
Cc: stable@vger.kernel.org
Signed-off-by: Raushan Patel <raushan.jhon@gmail.com>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2026-07-29 00:27:52 +09:00
Raushan PatelandMasami Hiramatsu (Google) 00a8ce2a2a tracing/probes: Reject $arg0 in meta argument expansion
traceprobe_expand_meta_args() parses $argN with simple_strtoul() and
calls sprint_nth_btf_arg(n - 1, ...). For $arg0, n is 0 so the index is
-1. Because ctx->nr_params is signed, the "idx >= nr_params" guard in
sprint_nth_btf_arg() does not catch the negative index, and
ctx->params[-1].name_off is read out of bounds.

The normal per-argument path (parse_probe_vars()) already rejects
$arg0 via its argument-number check, but meta-argument expansion runs
before per-argument parsing and substitutes the value first, bypassing
that check.

Reject $arg0 explicitly during expansion.

Link: https://lore.kernel.org/all/20260724054435.146279-1-raushan.jhon@gmail.com/

Fixes: 18b1e870a4 ("tracing/probes: Add $arg* meta argument for all function args")
Cc: stable@vger.kernel.org
Signed-off-by: Raushan Patel <raushan.jhon@gmail.com>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2026-07-28 23:58:31 +09:00
Linus Torvalds 864be1277d Merge tag 'trace-v7.2-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
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()
2026-07-26 09:15:59 -07:00
Steven Rostedt 2c2b322acd tracing: perf: Fix stale head for perf syscall tracing
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: edca33a562 ("tracing: Fix failure to read user space from system call trace events")
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-24 22:57:56 -04:00
Tengda WuandSteven Rostedt 7720b63bce ftrace: Add global mutex to serialize trace_parser access
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: e704eff3ff ("ftrace: Have set_graph_function handle multiple functions in one write")
Fixes: 689fd8b65d ("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>
2026-07-24 22:56:43 -04:00
Steven Rostedt e091351b38 tracing: Delay module ref count for "enable_event" trigger
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: 61d445af0a ("tracing: Add bulk garbage collection of freeing event_trigger_data")
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-24 18:49:51 -04:00
David CarlierandSteven Rostedt 7909781215 tracing: Fix use-after-free freeing trigger private data
Commit 61d445af0a ("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: 61d445af0a ("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>
2026-07-24 18:49:51 -04:00
Usama ArifandSteven Rostedt 8f76afb9b1 tracing: Fix context switch counter truncation
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: 64cf7d058a ("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>
2026-07-24 13:43:18 -04:00
Masami Hiramatsu (Google)andSteven Rostedt b4eb07bde6 tracing: 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. 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>
2026-07-24 13:43:17 -04:00
Steven Rostedt 144f29e857 tracing: Fix mmiotrace possible NULL dereferencing of hiter->dev
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: f984b51e07 ("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>
2026-07-24 13:43:09 -04:00
deepakraogandSteven Rostedt c1d87e724a tracing: Fix resource leak on mmiotrace trace_pipe close
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>
2026-07-23 12:30:07 -04:00
Jackie LiuandSteven Rostedt 655111f878 tracing: Propagate errors from remote event bulk updates
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>
2026-07-23 12:30:07 -04:00
Fuad TabbaandSteven Rostedt 94b83ff0c0 tracing/remotes: Fix page_va[] access before counter update in trace_remote_alloc_buffer()
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>
2026-07-22 16:53:29 -04:00
Masami Hiramatsu (Google) f418d68d71 tracing/eprobe: Fix exact system name matching in eprobe_dyn_event_match()
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>
2026-07-21 10:23:21 +09:00
Masami Hiramatsu (Google) 8ce20bfba4 tracing/probes: Fix potential underflow in LEN_OR_ZERO macro
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>
2026-07-21 10:23:17 +09:00
Masami Hiramatsu (Google) a9d6fb2840 tracing/probes: Prevent out-of-bounds write in __trace_probe_log_err()
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>
2026-07-21 10:23:13 +09:00
Masami Hiramatsu (Google) 15f197856d tracing/probes: Avoid temporary buffer truncation in trace_probe_match_command_args()
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>
2026-07-21 10:23:10 +09:00
Vincent DonnefortandSteven Rostedt 601ddaceb8 ring-buffer: Allow sparse CPU masks in ring_buffer_desc()
No user currently relies on sparse CPU masks, but the descriptor logic already
supports them via linear fallback. Remove the arbitrary limitation.

Link: https://patch.msgid.link/20260709160017.1729517-4-vdonnefort@google.com
Fixes: 2e67fabd8b ("ring-buffer: Introduce ring-buffer remotes")
Reported-by: Sashiko <sashiko-bot@kernel.org>
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-10 14:04:26 -04:00
Vincent DonnefortandSteven Rostedt d471d4f86e tracing/remotes: Fix struct_len in trace_remote_alloc_buffer()
Pre-calculate desc->struct_len up-front in trace_remote_alloc_buffer()
with trace_buffer_desc_size() to fix double-counting.

While at it, use the accessor __first_ring_buffer_desc().

Link: https://patch.msgid.link/20260709160017.1729517-3-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>
2026-07-10 14:04:26 -04:00
Vincent DonnefortandSteven Rostedt ec082d0b97 tracing/remotes: Fix leak in trace_remote_alloc_buffer() error path
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>
2026-07-10 14:04:26 -04:00
Yu PengandSteven Rostedt 05074bb90a tracing/synthetic: Free type string on error path
parse_synth_field() builds a "__data_loc ..." type string before
assigning it to field->type. If the seq_buf check fails, the common
cleanup cannot free the temporary string. Free it before leaving.

Link: https://patch.msgid.link/20260603062533.1096320-2-pengyu@kylinos.cn
Signed-off-by: Yu Peng <pengyu@kylinos.cn>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-07 13:59:55 -04:00
Michael BommaritoandSteven Rostedt 50fd6dd755 tracing/user_events: Fix use-after-free in user_event_mm_dup()
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>
2026-07-07 13:59:35 -04:00
Steven Rostedt 1e67bb60bb tracing: Add a no-rcu-check version of trace_##event##_enabled()
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>
2026-07-07 10:42:29 -04:00
Huihui HuangandSteven Rostedt 0a6070839b tracing: Prevent out-of-bounds read in glob matching
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>
2026-07-07 10:42:28 -04:00
Yuanhe ShuandSteven Rostedt c3e9460467 tracing: Fix NULL pointer dereference in func_set_flag()
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>
2026-07-07 10:42:28 -04:00
Ben DooksandSteven Rostedt d5c6785f94 tracing: Make tracepoint_printk static as not exported
The tracepoint_printk symbol is not exported, so make it
static to remove the following sparse warning:

kernel/trace/trace.c:90:5: warning: symbol 'tracepoint_printk' was not declared. Should it be static?

Fixes: dd293df639 ("tracing: Move trace sysctls into trace.c")
Link: https://patch.msgid.link/20260617105822.904164-1-ben.dooks@codethink.co.uk
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-07 10:39:12 -04:00
David CarlierandSteven Rostedt af05b4e062 ring-buffer: Fix ring_buffer_read_page() copying only one event per page
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>
2026-07-07 10:38:03 -04:00
Wayen.YanandSteven Rostedt a20b08de86 tracing: Remove unused ret assignment in tracing_set_tracer()
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>
2026-07-06 15:00:01 -04:00
Crystal WoodandSteven Rostedt fe58f457ad tracing/osnoise: Call synchronize_rcu() when unregistering
This ensures that any RCU readers traversing the instance list
have finished, before releasing the reference on the tracer that
the instance points to.

Cc: stable@vger.kernel.org
Fixes: a6ed2aee54 ("tracing: Switch to kvfree_rcu() API")
Link: https://patch.msgid.link/20260609045430.1589786-1-crwood@redhat.com
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Crystal Wood <crwood@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-06 14:56:18 -04:00
Hui WangandSteven Rostedt c37e0a4b79 ring-buffer: Fix event length with forced 8-byte alignment
When RB_FORCE_8BYTE_ALIGNMENT is true, rb_calculate_event_length()
reserves the space of event->array[0] for placing the data length and
rb_update_event() stores the data length in event->array[0]
accordingly. As a result the whole event length will add extra 4 bytes
for sizeof(event.array[0]) unconditionally.

But ring_buffer_event_length() only subtracts the
sizeof(event->array[0]) for events larger than RB_MAX_SMALL_DATA +
sizeof(event->array[0]). As a result, small events on architectures
with RB_FORCE_8BYTE_ALIGNMENT=true report a data length that is 4
bytes larger than expected.

To fix it, add the RB_FORCE_8BYTE_ALIGNMENT as a condition to subtract
the size of that length field whenever RB_FORCE_8BYTE_ALIGNMENT is
true.

This issue is observed in a riscv64 kernel with
CONFIG_HAVE_64BIT_ALIGNED_ACCESS set to y, when we run ftrace selftest
trace_marker_raw.tc, we get the weird log: for cases where the id is
1..100, the number of data field is 8*N, but once id exceeds 100, the
number of data field becomes 8*N+4:
 # 1 buf: 58 00 00 00 80 5e d1 63 (number of data field is 8*1)
 ...
 # a buf: 58 ...                  (number of data field is 8*2)
 ...
 # 64 buf: 58 ...                 (number of data field is 8*13)
 # 65 buf: 58 ...                 (number of data field is 8*13+4)

After applying this change, the number of data field keeps being 8*N+4
consistently.

Link: https://patch.msgid.link/20260607072431.125633-2-hui.wang@canonical.com
Fixes: 2271048d1b ("ring-buffer: Do 8 byte alignment for 64 bit that can not handle 4 byte align")
Signed-off-by: Hui Wang <hui.wang@canonical.com>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-06 14:52:14 -04:00
Yu PengandSteven Rostedt 15d9968b68 tracing/synthetic: Free pending field on error path
Some __create_synth_event() error paths run after parse_synth_field()
succeeds but before the field is stored in fields[]. The common cleanup
then misses the field. Free it before freeing argv.

Link: https://patch.msgid.link/20260603062533.1096320-1-pengyu@kylinos.cn
Signed-off-by: Yu Peng <pengyu@kylinos.cn>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-06 13:04:19 -04:00
Linus Torvalds 665159e246 Merge tag 'probes-fixes-v7.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull probes fixes from Masami Hiramatsu:
 "fprobe fixes and spelling typos:

   - Fix NULL pointer dereference in fprobe_fgraph_entry(). Prevent
     general protection faults by checking shadow-stack reservation
     bounds. Skip mid-flight registered fprobes that were not counted
     during sizing.

  eprobe: fix string pointer extraction

   - Correct the casting of string pointers read from the ringbuffer to
     prevent truncation of base event pointer variables when
     dereferencing FILTER_PTR_STRING fields.

  tracing/probes: clean up argument parsing and BTF helper logic

   - Make the $ prefix mandatory for comm access: Require the $ prefix
     for special fetcharg variables like $comm and $COMM, preventing
     naming conflicts with regular BTF-based event fields.

   - Fix double addition of offset for @+FOFFSET: Clear the temporary
     offset variable after setting the FETCH_OP_FOFFS instruction to
     avoid applying the offset multiple times.

   - Remove WARN_ON_ONCE from parse_btf_arg: Prevent triggering a kernel
     warning via user-space input when creating a kprobe event on a raw
     address.

   - Fix typo in a log message: Correct a spelling error ("$-valiable")
     in trace probe log messages.

  samples/trace_events: improve error checking

   - Validate the thread pointer returned from kthread_run() in the
     trace events sample code to properly handle thread creation
     failures"

* tag 'probes-fixes-v7.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing/probes: Make the $ prefix mandatory for comm access
  tracing/fprobe: Fix NULL pointer dereference in fprobe_fgraph_entry()
  tracing/probes: Fix double addition of offset for @+FOFFSET
  tracing: eprobe: read the complete FILTER_PTR_STRING pointer
  tracing/events: Fix to check the simple_tsk_fn creation
  tracing/probes: Remove WARN_ON_ONCE from parse_btf_arg
  tracing: probes: fix typo in a log message
2026-06-30 17:50:44 -10:00
Masami Hiramatsu (Google) a369299c3f tracing/probes: Make the $ prefix mandatory for comm access
Since $comm or $COMM are not event field but special fetcharg
variables to access current->comm, It should not be accessed
without '$' prefix even with typecast.

Link: https://lore.kernel.org/all/178231209724.732967.12049805699091810641.stgit@devnote2/

Fixes: 69efd863a7 ("tracing/eprobes: Allow use of BTF names to dereference pointers")
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2026-06-30 23:58:20 +09:00
Sechang LimandMasami Hiramatsu (Google) 367c49d6e2 tracing/fprobe: Fix NULL pointer dereference in fprobe_fgraph_entry()
fprobe_fgraph_entry() sizes a shadow-stack reservation in one walk of
the per-ip fprobe list and fills it in a second walk, both under
rcu_read_lock() only. A fprobe registered on an already-live ip can
become visible between the two walks, so the fill walk processes an
exit_handler the sizing walk did not count and used runs past
reserved_words. If the sizing walk counted nothing, fgraph_data is NULL
and the first write_fprobe_header() faults:

  Oops: general protection fault, probably for non-canonical address ...
  KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
  RIP: 0010:fprobe_fgraph_entry+0xa38/0xf10 kernel/trace/fprobe.c:167
  Call Trace:
   <TASK>
   function_graph_enter_regs+0x44c/0xa10 kernel/trace/fgraph.c:677
   ftrace_graph_func+0xc5/0x140 arch/x86/kernel/ftrace.c:671
   __kernel_text_address+0x9/0x40 kernel/extable.c:78
   arch_stack_walk+0x117/0x170 arch/x86/kernel/stacktrace.c:26
   kmem_cache_free+0x188/0x580 mm/slub.c:6378
   tcp_data_queue+0x18d/0x6550 net/ipv4/tcp_input.c:5590
   [...]
   </TASK>

The list cannot be frozen across the two walks, so skip a node that does
not fit the reservation and count it as missed.

Link: https://lore.kernel.org/all/20260619184425.3824774-1-rhkrqnwk98@gmail.com/

Fixes: 4346ba1604 ("fprobe: Rewrite fprobe on function-graph tracer")
Signed-off-by: Sechang Lim <rhkrqnwk98@gmail.com>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2026-06-30 23:58:19 +09:00
Masami Hiramatsu (Google) 9a667b7750 tracing/probes: Fix double addition of offset for @+FOFFSET
Since commit 533059281e ("tracing: probeevent: Introduce new argument
 fetching code") wrongly use @offset local variable during the parsing,
the offset value is added twice when dereferencing.
Reset the @offset after setting it in FETCH_OP_FOFFS.

Link: https://lore.kernel.org/all/178217905962.643090.1978577464942171332.stgit@devnote2/

Fixes: 533059281e ("tracing: probeevent: Introduce new argument fetching code")
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: stable@vger.kernel.org
2026-06-30 23:58:19 +09:00
Martin KaiserandMasami Hiramatsu (Google) 206b25c090 tracing: eprobe: read the complete FILTER_PTR_STRING pointer
For a char * element in an event, the FILTER_PTR_STRING filter type is
used. When the event occurs, a pointer is stored in the ringbuffer.

If an eprobe references such a char * element of a "base event", the
stored pointer is truncated when it's read from the ringbuffer.

$ cd /sys/kernel/tracing
$ echo 'e rcu.rcu_utilization $s:x64 $s:string' > dynamic_events
$ echo 1 > tracing_on
$ echo 1 > events/eprobes/enable
$ sleep 1
$ echo 0 > events/eprobes/enable
$ cat trace
   <idle>-0  ...: (rcu.rcu_utilization) arg1=0x4f arg2=(fault)
   <idle>-0  ...: (rcu.rcu_utilization) arg1=0x2 arg2=(fault)

The problem is in get_event_field

	val = (unsigned long)(*(char *)addr);

addr points to the position in the ringbuffer where the pointer was
stored. The assignment reads only the lowest byte of the pointer.

Fix the cast to read the whole pointer. The output of the test above
is now

<idle>-0 ... arg1=0xffffffff81c7d3f3 arg2="Start scheduler-tick"
<idle>-0 ... arg1=0xffffffff81c57340 arg2="End scheduler-tick"

Link: https://lore.kernel.org/all/20260620145339.3234726-1-martin@kaiser.cx/

Fixes: f04dec9346 ("tracing/eprobes: Fix reading of string fields")
Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2026-06-30 23:58:19 +09:00
Masami Hiramatsu (Google) 251a8fe1b9 tracing/probes: Remove WARN_ON_ONCE from parse_btf_arg
Sashiko found that user can cause this WARN_ON_ONCE() easily
with adding a kprobe event based on a raw address with BTF
parameter.

Since this is not an unexpected condition, remove the
WARN_ON_ONCE().

Link: https://lore.kernel.org/all/178177265367.2059927.13789953014706792126.stgit@mhiramat.tok.corp.google.com/

Link: https://sashiko.dev/#/patchset/178165816303.269421.7302603996990753309.stgit%40devnote2

Reported-by: Sashiko <sashiko-bot@kernel.org>
Fixes: b576e09701 ("tracing/probes: Support function parameters if BTF is available")
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2026-06-30 23:58:19 +09:00
Martin KaiserandMasami Hiramatsu (Google) 72c8646956 tracing: probes: fix typo in a log message
Fix a typo ("Invalid $-variable") in a log message.

Link: https://lore.kernel.org/all/20260507081041.885781-4-martin@kaiser.cx/

Fixes: ab105a4fb8 ("tracing: Use tracing error_log with probe events")
Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2026-06-25 08:34:45 +09:00
Jiri OlsaandAlexei Starovoitov d5dc200c3a bpf: Add missing access_ok call to copy_user_syms
As reported by sashiko we use __get_user without prior access_ok call on the
user space pointer. Adding the missing call for the whole pointer array.

Plus removing the err check in the error path, because it's not needed and
also we can return -ENOMEM directly from the first kvmalloc_array fail path.

Cc: stable@vger.kernel.org
[1] https://lore.kernel.org/bpf/20260611115503.AC16D1F00893@smtp.kernel.org/
Fixes: 0236fec57a ("bpf: Resolve symbols with ftrace_lookup_symbols for kprobe multi link")
Reported-by: Sashiko <sashiko-bot@kernel.org>
Closes: https://lore.kernel.org/bpf/20260611115503.AC16D1F00893@smtp.kernel.org/
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Link: https://lore.kernel.org/r/20260616083056.405652-1-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-06-21 18:01:33 -07:00
Linus Torvalds 9ecfb2f728 Merge tag 'trace-ring-buffer-v7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull ring-buffer updates from Steven Rostedt

 - Do not invalidate entire buffer for invalid sub-buffers

   For the persistent ring buffer, if one sub-buffer is found to be
   invalid, it invalidates the entire per CPU ring buffer. This can lose
   a lot of valuable data if there's some corruption with the writes to
   the buffer not syncing properly on a hard crash. Instead, if a
   sub-buffer is found to be invalid, simply zero it out and mark it for
   "missed events".

   When the persistent ring buffer is read and a sub-buffer that was
   cleared due to being invalid on boot up is discovered, the output
   will show "[LOST EVENTS]" to let the user know that events were
   missing at that location. Displaying the events from valid buffers
   can still be useful.

 - Add a test to be able to test corrupted sub-buffers

   If a persistent ring buffer is created as "ptraingtest" and the new
   config that adds the test is enabled, when a panic happens, the
   kernel will randomly corrupt one of the per CPU ring buffers. On boot
   up, the sub-buffers with the corruption should be cleared and
   flagged. When reading this buffer, the missed events should should
   [LOST EVENTS].

 - Add commit number in the sub-buffer meta debug info

   The commit is used to know the content of a meta page. Add it to the
   buffer_meta file that is shown for each per CPU buffer.

 - Clean up the persistent ring buffer validation code

   Add some helper functions and make variable names more consistent.

* tag 'trace-ring-buffer-v7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Better comment the use of RB_MISSED_EVENTS
  ring-buffer: Show persistent buffer dropped events in trace_pipe file
  ring-buffer: Show persistent buffer dropped events in trace file
  ring-buffer: Have dropped subbuffers be persistent across reboots
  ring-buffer: Cleanup buffer_data_page related code
  ring-buffer: Cleanup persistent ring buffer validation
  ring-buffer: Show commit numbers in buffer_meta file
  ring-buffer: Add persistent ring buffer invalid-page inject test
  ring-buffer: Skip invalid sub-buffers when rewinding persistent ring buffer
  ring-buffer: Skip invalid sub-buffers when validating persistent ring buffer
2026-06-18 21:23:22 -07:00
Linus Torvalds 23b5d045ae Merge tag 'trace-v7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing updates from Steven Rostedt:

 - Remove a redundant IS_ERR() check

   trace_pipe_open() already checks for IS_ERR() and does it again in
   the return path. Remove the return check.

 - Export seq_buf_putmem_hex() to allow kunit tests against them

   To add Kunit tests on seq_buf_putmem_hex(), it needs to be exported.

 - Replace strcat() and strcpy() with seq_buf() logic

   The code for synthetic events uses a series of strcat() and strcpy()
   which can be error prone. Replace them with seq_buf() logic that does
   all the necessary bound checking.

 - Add a lockdep rcu_is_watching() to trace_##event##_enabled() call

   The trace_##event##_enabled() is a static branch that is true if the
   "event" is enabled. But this can hide bugs if this logic is in a
   location where RCU is disabled and not "watching". It would only
   trigger if lockdep is enabled and the event is enabled.

   Add a "rcu_is_watching()" warning if lockdep is enabled in that
   helper function to trigger regardless if the event is enabled or not.

 - Remove the local variable in the trace_printk() macro

   For name space integrity, remove the _______STR variable in the
   trace_printk() macro for using the sizeof() macro directly.

 - Use guard()s for the trace_recursion_record.c file

 - Fix typo in a comment of eventfs_callback() kerneldoc

 - Use trace_call__##event() in events within trace_##event##_enabled()

   A couple of events are called within an if block guarded by
   trace_##event##_enabled(). That is a static key that is only enabled
   when the event is enabled. The trace_call_##event() calls the
   tracepoint code directly without adding a redundant static key for
   that check.

 - Allow perf to read synthetic events

   Currently, perf does not have the ability to enable a synthetic
   event. If it does, it will either cause a kernel warning or error
   with "No such device". Synthetic events are not much different than
   kprobes and perf can handle fine with a few modifications.

 - Replace printk(KERN_WARNING ...) with pr_warn()

 - Replace krealloc() on an array with krealloc_array()

 - Fix README file path name for synthetic events

 - Change tracing_map tracing_map_array to use a flexible array

   Instead of allocating a separate pointer to hold the pages field of
   tracing_map_array, allocate the pages field as a flexible array when
   allocating the structure.

 - Fold trace_iterator_increment() into trace_find_next_entry_inc()

   The function trace_iterator_increment() was only used by
   trace_find_next_entry_inc(). It's not big enough to be a helper
   function for one user. Fold it into its caller.

 - Make field_var_str field a flexible array of hist_elt_data

   Instead of allocating a separate pointer for the field_var_str array
   of the hist_elt_data structure, allocate it as a flexible array when
   allocating the structure.

 - Disable KCOV for trace_irqsoff.c

   Like trace_preemptirq.c, trace_irqsoff.c has code that will crash
   when KCOV is enabled on ARM. The irqsoff tracing can be called on ARM
   because the irqsoff tracing code can be run from early interrupt code
   and produce coverage unrelated to syscall inputs.

 - Fix warning in __unregister_ftrace_function() called by perf

   Perf calls unregister_ftrace_function() without checking if its
   ftrace_ops has already been unregistered. There's an error path where
   on clean up it will unregister the ftrace_ops even if it wasn't
   registered and causes a warning.

* tag 'trace-v7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  perf/ftrace: Fix WARNING in __unregister_ftrace_function
  tracing: Disable KCOV instrumentation for trace_irqsoff.o
  tracing: Turn hist_elt_data field_var_str into a flexible array
  tracing: Move trace_iterator_increment() into trace_find_next_entry_inc()
  tracing: Simplify pages allocation for tracing_map logic
  tracing: Fix README path for synthetic_events
  tracing: Use krealloc_array() for trace option array growth
  tracing/branch: Use pr_warn() instead of printk(KERN_WARNING)
  tracing: Allow perf to read synthetic events
  HID: Use trace_call__##name() at guarded tracepoint call sites
  cpufreq: amd-pstate: Use trace_call__##name() at guarded tracepoint call site
  tracefs: Fix typo in a comment of eventfs_callback() kerneldoc
  tracing: Switch trace_recursion_record.c code over to use guard()
  tracing: Remove local variable for argument detection from trace_printk()
  tracepoint: Add lockdep rcu_is_watching() check to trace_##name##_enabled()
  tracing: Bound synthetic-field strings with seq_buf
  seq_buf: Export seq_buf_putmem_hex() and add KUnit tests
  tracing: Remove redundant IS_ERR() check in trace_pipe_open()
2026-06-18 20:53:00 -07:00
Linus Torvalds 9c87e61e3c Merge tag 'bpf-next-7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Pull bpf updates from Alexei Starovoitov:
 "Major changes:

   - Recover from BPF arena page faults using a scratch page and add
     ptep_try_set() for lockless empty-slot installs on x86 and arm64.

     This allows BPF kfuncs to access arena pointers directly.

     The 'arena_direct_access' stable branch was created for this work
     and was pulled into sched-ext and bpf-next trees (Tejun Heo, Kumar
     Kartikeya Dwivedi)

   - Lift old restriction and support 6+ arguments in BPF programs and
     kfuncs on x86 and arm64 (Yonghong Song, Puranjay Mohan)

  Other features and fixes:

   - Add 24-bit BTF vlen and reclaim unused bits in the BTF UAPI to ease
     addition of new BTF kinds (Alan Maguire)

   - Raise the maximum BPF call chain depth from 8 to 16 frames (Alexei
     Starovoitov)

   - Refactor object relationship tracking in the verifier and fix a
     dynptr use-after-free bug (Amery Hung)

   - Harden the signed program loader and reject exclusive maps as inner
     maps (Daniel Borkmann)

   - Replace the verifier min/max bounds fields with a circular number
     (cnum) representation and improve 32->64 bit range refinements
     (Eduard Zingerman)

   - Introduce the arena library and runtime (libarena) with a buddy
     allocator, rbtree and SPMC queue data structures, ASAN support and
     a parallel test harness. Allow subprograms to return arena pointers
     and switch to a BTF type-tag based __arena annotation (Emil
     Tsalapatis)

   - Cache build IDs in the sleepable stackmap path and avoid faultable
     build ID reads under mm locks (Ihor Solodrai)

   - Introduce the tracing_multi link to attach a single BPF program to
     many kernel functions at once. Allow specifying the uprobe_multi
     target via FD (Jiri Olsa)

   - Extend the bpf_list family of kfuncs with bpf_list_add/del(), and
     bpf_list_is_first/is_last/empty() (Kaitao Cheng)

   - Extend the BPF syscall with common attributes support for
     prog_load, btf_load and map_create (Leon Hwang)

   - Wrap rhashtable as BPF map (Mykyta Yatsenko, Herbert Xu)

   - Add sleepable support for tracepoint programs and fix deadlocks in
     LRU map due to NMI reentry (Mykyta Yatsenko)

   - Fix OOB access in bpf_flow_keys, fix nullness analysis of inner
     arrays, enforce write checks for global subprograms (Nuoqi Gui)

   - Report the maximum combined stack depth and print a breakdown of
     instructions processed per subprogram (Paul Chaignon)

   - Add an XDP load-balancer benchmark and arm64 JIT support for stack
     arguments (Puranjay Mohan)

   - Add kfuncs to traverse over wakeup_sources (Samuel Wu)

   - Allow sleepable BPF programs to use LPM trie maps directly (Vlad
     Poenaru)

   - Many more fixes and cleanups across the verifier, BTF, sockmap,
     devmap, bpffs, security hooks, s390/riscv/loongarch JITs,
     rqspinlock, libbpf, bpftool, selftests"

* tag 'bpf-next-7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (336 commits)
  selftests/bpf: Work around llvm stack overflow in crypto progs
  selftests/bpf: add test for bpf_msg_pop_data() overflow
  bpf, sockmap: fix integer overflow in bpf_msg_pop_data() bounds check
  sockmap: Fix use-after-free in udp_bpf_recvmsg()
  bpf, sockmap: keep sk_msg copy state in sync
  bpf, sockmap: Fix wrong rsge offset in bpf_msg_push_data()
  bpf, sockmap: reject overflowing copy + len in bpf_msg_push_data()
  selftsets/bpf: Retry map update on helper_fill_hashmap()
  selftests/bpf: Add test for sleepable lsm_cgroup rejection
  selftests/bpf: Add test to verify the fix for bpf_setsockopt() helper
  bpf: Fix bpf_get/setsockopt to tos for ipv4-mapped ipv6 socket
  selftests/bpf: Avoid static LLVM linking for cross builds
  selftests/bpf: Use common CFLAGS for urandom_read
  selftests/bpf: Initialize operation name before use
  tools/bpf: build: Append extra cflags
  libbpf: Initialize CFLAGS before including Makefile.include
  bpftool: Append extra host flags
  bpftool: Avoid adding EXTRA_CFLAGS to HOST_CFLAGS
  bpftool: Pass host flags to bootstrap libbpf
  selftests/bpf: correct CONFIG_PPC64 macro name in comment
  ...
2026-06-17 09:18:14 +01:00