[PATCH kernel-next] tracing: Fix uninitialized variable in tracing_set_tracer()

[PATCH kernel-next] tracing: Fix uninitialized variable in tracing_set_tracer()

[Dheeraj Reddy Jonnalagadda]

Fix an issue in the tracing_set_tracer() where the variable ret could
be used uninitialized under certain conditions. Specifically, when
t->use_max_tr is true but tr->cond_snapshot is false, the code would
check the value of ret without first initializing it.

Fixes: a35873a0993b ("tracing: Add conditional snapshot")
Closes: https://scan7.scan.coverity.com/#/project-view/52337/11354?selectedIssue=1602786
Signed-off-by: Dheeraj Reddy Jonnalagadda <dheeraj.linuxdev@gmail.com>
---
 kernel/trace/trace.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index a04348ab7ccc..28f111c5b3a5 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -6079,7 +6079,7 @@ int tracing_set_tracer(struct trace_array *tr, const char *buf)
 #ifdef CONFIG_TRACER_MAX_TRACE
 	bool had_max_tr;
 #endif
-	int ret;
+	int ret = 0;
 
 	guard(mutex)(&trace_types_lock);
 
-- 
2.34.1

Re: [PATCH kernel-next] tracing: Fix uninitialized variable in tracing_set_tracer()

[Steven Rostedt]

On Tue,  7 Jan 2025 18:29:20 +0530
Dheeraj Reddy Jonnalagadda <dheeraj.linuxdev@gmail.com> wrote:

> Fix an issue in the tracing_set_tracer() where the variable ret could
> be used uninitialized under certain conditions. Specifically, when
> t->use_max_tr is true but tr->cond_snapshot is false, the code would
> check the value of ret without first initializing it.
> 
> Fixes: a35873a0993b ("tracing: Add conditional snapshot")
> Closes: https://scan7.scan.coverity.com/#/project-view/52337/11354?selectedIssue=1602786
> Signed-off-by: Dheeraj Reddy Jonnalagadda <dheeraj.linuxdev@gmail.com>
> ---
>  kernel/trace/trace.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> index a04348ab7ccc..28f111c5b3a5 100644
> --- a/kernel/trace/trace.c
> +++ b/kernel/trace/trace.c
> @@ -6079,7 +6079,7 @@ int tracing_set_tracer(struct trace_array *tr, const char *buf)
>  #ifdef CONFIG_TRACER_MAX_TRACE
>  	bool had_max_tr;
>  #endif
> -	int ret;
> +	int ret = 0;
>  
>  	guard(mutex)(&trace_types_lock);
>  

Incorrect fix. The actual fix is pending:

  https://lore.kernel.org/all/20250106111143.2f90ff65@gandalf.local.home/

-- Steve