linux-stable.git/kernel/trace, branch v6.18.42 Linux kernel stable tree ftrace: Add global mutex to serialize trace_parser access 2026-08-03T09:22:02+00:00 Tengda Wu wutengda@huaweicloud.com 2026-07-25T02:47:21+00:00 65bf73bee1a4f3722208ae46afc0fa5de76b9a0a commit 7720b63bcef3f54c7fe288774b720a227d54a306 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 7720b63bcef3f54c7fe288774b720a227d54a306 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tracing/probes: Prevent out-of-bounds write in __trace_probe_log_err() 2026-08-03T09:22:00+00:00 Masami Hiramatsu (Google) mhiramat@kernel.org 2026-07-20T10:12:20+00:00 9025946adec9a97d6cd599c718be0056fa182020 commit a9d6fb284039a5d3858a1d9f9a0d7e46cfb7c2d4 upstream. 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: ab105a4fb894 ("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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit a9d6fb284039a5d3858a1d9f9a0d7e46cfb7c2d4 upstream.

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: ab105a4fb894 ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tracing/probes: Fix potential underflow in LEN_OR_ZERO macro 2026-08-03T09:22:00+00:00 Masami Hiramatsu (Google) mhiramat@kernel.org 2026-07-20T10:12:29+00:00 3b3be8653c594d394c0c2763140d865477c4bd8b commit 8ce20bfba48902e1382187cd1a852f7cf3a1e739 upstream. 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: 5bf652aaf46c ("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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 8ce20bfba48902e1382187cd1a852f7cf3a1e739 upstream.

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: 5bf652aaf46c ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tracing/probes: Avoid temporary buffer truncation in trace_probe_match_command_args() 2026-08-03T09:22:00+00:00 Masami Hiramatsu (Google) mhiramat@kernel.org 2026-07-20T10:12:10+00:00 949ac1aeb37b87e93660dcf89459f018f0c62ee2 commit 15f197856d68882af9416fc97516bb55079b7677 upstream. 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: eb5bf81330a7 ("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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 15f197856d68882af9416fc97516bb55079b7677 upstream.

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: eb5bf81330a7 ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tracing/eprobe: Fix exact system name matching in eprobe_dyn_event_match() 2026-08-03T09:22:00+00:00 Masami Hiramatsu (Google) mhiramat@kernel.org 2026-07-20T10:12:38+00:00 6b5098d7458117fb67b188fbac07a5ce6546ffe2 commit f418d68d71fd4a0a9cef92377bc8c4c3334b5b53 upstream. 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: 7d5fda1c841f ("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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit f418d68d71fd4a0a9cef92377bc8c4c3334b5b53 upstream.

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: 7d5fda1c841f ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tracing: Fix union collision of module and refcnt for dynamic events 2026-08-03T09:22:00+00:00 Masami Hiramatsu (Google) mhiramat@kernel.org 2026-07-17T02:51:49+00:00 b6a4575f22925da7e6aa00171e9fc0e5029c0bc9 commit b4eb07bde606c2096b24252be589e735eff6d413 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit b4eb07bde606c2096b24252be589e735eff6d413 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tracing: Fix resource leak on mmiotrace trace_pipe close 2026-08-03T09:22:00+00:00 deepakraog gaikwad.dcg@gmail.com 2026-07-15T14:36:04+00:00 cf5a82bef623b969a609f2b7e392d06dbae34aa6 commit c1d87e724ae55e781b7cc7ccafb34d9e668582b2 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit c1d87e724ae55e781b7cc7ccafb34d9e668582b2 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tracing: Fix mmiotrace possible NULL dereferencing of hiter->dev 2026-08-03T09:22:00+00:00 Steven Rostedt rostedt@goodmis.org 2026-07-22T01:11:43+00:00 8464427e1c177809a9488a97dfa2807d9dcf323b commit 144f29e85702234b23d2a62abf723e6a17eb5427 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 144f29e85702234b23d2a62abf723e6a17eb5427 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tracing: Fix context switch counter truncation 2026-08-03T09:22:00+00:00 Usama Arif usama.arif@linux.dev 2026-07-17T17:32:52+00:00 1f2e7cd0ff9766983650dfa9b3e4d231ccd1ce37 commit 8f76afb9b114bee1c1251e0e52553e9dc7c59f20 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 8f76afb9b114bee1c1251e0e52553e9dc7c59f20 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tracing/osnoise: Call synchronize_rcu() when unregistering 2026-07-24T14:17:16+00:00 Crystal Wood crwood@redhat.com 2026-06-09T04:54:30+00:00 fad36954b29592ce463254179c3043697678481f commit fe58f457ad8d0a2bef4e053cfecca4b5cd266b1a upstream. 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: a6ed2aee54644 ("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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit fe58f457ad8d0a2bef4e053cfecca4b5cd266b1a upstream.

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: a6ed2aee54644 ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>