Re: [PATCH v1] tracing/remotes: Fix leak in trace_remote_alloc_buffer() error path

[Steven Rostedt <rostedt@goodmis.org>]

On Wed,  8 Jul 2026 14:32:01 +0100
Vincent Donnefort <vdonnefort@google.com> wrote:

> 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().
> 
> Include the failing CPU in desc->nr_cpus before going to the error path.
> 

Looks like Sashiko found other issues you may want to address:

  https://sashiko.dev/#/patchset/20260708133201.295072-1-vdonnefort%40google.com

-- Steve

> Fixes: 96e43537af54 ("tracing: Introduce trace remotes")
> Reported-by: Sashiko <sashiko-bot@kernel.org>
> Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
> 
> diff --git a/kernel/trace/trace_remote.c b/kernel/trace/trace_remote.c
> index 2a6cc000ec98..62d3d431c309 100644
> --- a/kernel/trace/trace_remote.c
> +++ b/kernel/trace/trace_remote.c
> @@ -1008,8 +1008,10 @@ int trace_remote_alloc_buffer(struct trace_buffer_desc *desc, size_t desc_size,
>  
>  		for (id = 0; id < nr_pages; id++) {
>  			rb_desc->page_va[id] = (unsigned long)__get_free_page(GFP_KERNEL);
> -			if (!rb_desc->page_va[id])
> +			if (!rb_desc->page_va[id]) {
> +				desc->nr_cpus++; /* Free this partially-allocated rb_desc */
>  				goto err;
> +			}
>  
>  			rb_desc->nr_page_va++;
>  		}
> 
> base-commit: 8cdeaa50eae8dad34885515f62559ee83e7e8dda