* [for-linus][PATCH 1/3] tracing: branch: Fix inverted check on stat tracer registration
2026-04-29 20:14 [for-linus][PATCH 0/3] tracing: Fixes for v7.1 Steven Rostedt
@ 2026-04-29 20:14 ` Steven Rostedt
2026-04-29 20:14 ` [for-linus][PATCH 2/3] tracepoint: Fix typo in tracepoint.h comment Steven Rostedt
2026-04-29 20:14 ` [for-linus][PATCH 3/3] tracing/probes: Limit size of event probe to 3K Steven Rostedt
2 siblings, 0 replies; 4+ messages in thread
From: Steven Rostedt @ 2026-04-29 20:14 UTC (permalink / raw)
To: linux-kernel
Cc: Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Andrew Morton,
Ingo Molnar, Frederic Weisbecker, Breno Leitao
From: Breno Leitao <leitao@debian.org>
init_annotated_branch_stats() and all_annotated_branch_stats() check the
return value of register_stat_tracer() with "if (!ret)", but
register_stat_tracer() returns 0 on success and a negative errno on
failure. The inverted check causes the warning to be printed on every
successful registration, e.g.:
Warning: could not register annotated branches stats
while leaving real failures silent. The initcall also returned a
hard-coded 1 instead of the actual error.
Invert the check and propagate ret so that the warning fires on real
errors and the initcall reports the correct status.
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: https://patch.msgid.link/20260420-tracing-v1-1-d8f4cd0d6af1@debian.org
Fixes: 002bb86d8d42 ("tracing/ftrace: separate events tracing and stats tracing engine")
Signed-off-by: Breno Leitao <leitao@debian.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
kernel/trace/trace_branch.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c
index 6809b370e991..d1564db95a8f 100644
--- a/kernel/trace/trace_branch.c
+++ b/kernel/trace/trace_branch.c
@@ -373,10 +373,10 @@ __init static int init_annotated_branch_stats(void)
int ret;
ret = register_stat_tracer(&annotated_branch_stats);
- if (!ret) {
+ if (ret) {
printk(KERN_WARNING "Warning: could not register "
"annotated branches stats\n");
- return 1;
+ return ret;
}
return 0;
}
@@ -438,10 +438,10 @@ __init static int all_annotated_branch_stats(void)
int ret;
ret = register_stat_tracer(&all_branch_stats);
- if (!ret) {
+ if (ret) {
printk(KERN_WARNING "Warning: could not register "
"all branches stats\n");
- return 1;
+ return ret;
}
return 0;
}
--
2.53.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* [for-linus][PATCH 3/3] tracing/probes: Limit size of event probe to 3K
2026-04-29 20:14 [for-linus][PATCH 0/3] tracing: Fixes for v7.1 Steven Rostedt
2026-04-29 20:14 ` [for-linus][PATCH 1/3] tracing: branch: Fix inverted check on stat tracer registration Steven Rostedt
2026-04-29 20:14 ` [for-linus][PATCH 2/3] tracepoint: Fix typo in tracepoint.h comment Steven Rostedt
@ 2026-04-29 20:14 ` Steven Rostedt
2 siblings, 0 replies; 4+ messages in thread
From: Steven Rostedt @ 2026-04-29 20:14 UTC (permalink / raw)
To: linux-kernel
Cc: Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Andrew Morton,
stable
From: Steven Rostedt <rostedt@goodmis.org>
There currently isn't a max limit an event probe can be. One could make an
event greater than PAGE_SIZE, which makes the event useless because if
it's bigger than the max event that can be recorded into the ring buffer,
then it will never be recorded.
A event probe should never need to be greater than 3K, so make that the
max size. As long as the max is less than the max that can be recorded
onto the ring buffer, it should be fine.
Cc: stable@vger.kernel.org
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Fixes: 93ccae7a22274 ("tracing/kprobes: Support basic types on dynamic events")
Link: https://patch.msgid.link/20260428122302.706610ba@gandalf.local.home
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
kernel/trace/trace_probe.c | 6 ++++++
kernel/trace/trace_probe.h | 4 +++-
2 files changed, 9 insertions(+), 1 deletion(-)
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index e1c73065dae5..e0d3a0da26af 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -1523,6 +1523,12 @@ static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size,
parg->offset = *size;
*size += parg->type->size * (parg->count ?: 1);
+ if (*size > MAX_PROBE_EVENT_SIZE) {
+ ret = -E2BIG;
+ trace_probe_log_err(ctx->offset, EVENT_TOO_BIG);
+ goto fail;
+ }
+
if (parg->count) {
len = strlen(parg->type->fmttype) + 6;
parg->fmt = kmalloc(len, GFP_KERNEL);
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
index 9fc56c937130..262d8707a3df 100644
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -38,6 +38,7 @@
#define MAX_BTF_ARGS_LEN 128
#define MAX_DENTRY_ARGS_LEN 256
#define MAX_STRING_SIZE PATH_MAX
+#define MAX_PROBE_EVENT_SIZE 3072
/* Reserved field names */
#define FIELD_STRING_IP "__probe_ip"
@@ -561,7 +562,8 @@ extern int traceprobe_define_arg_fields(struct trace_event_call *event_call,
C(BAD_TYPE4STR, "This type does not fit for string."),\
C(NEED_STRING_TYPE, "$comm and immediate-string only accepts string type"),\
C(TOO_MANY_ARGS, "Too many arguments are specified"), \
- C(TOO_MANY_EARGS, "Too many entry arguments specified"),
+ C(TOO_MANY_EARGS, "Too many entry arguments specified"), \
+ C(EVENT_TOO_BIG, "Event too big (too many fields?)"),
#undef C
#define C(a, b) TP_ERR_##a
--
2.53.0
^ permalink raw reply related [flat|nested] 4+ messages in thread