Re: [PATCH 1/2] tracing: Check total refcount before releasing bufs in profile_enable failure

[Paul Mackerras]

Frederic Weisbecker writes:

> When we call the profile_enable() callback of an event, we release the
> shared perf event tracing buffers unconditionnaly in the failure path.
> This is wrong because there may be other users of these. Then check the
> total refcount before doing this.

[snip]

> -	kfree(trace_profile_buf_nmi);
>  fail_buf_nmi:
> -	kfree(trace_profile_buf);
> +	if (!total_profile_count) {

A small problem here: total_profile_count will be 1, not 0, in the
case where we need to free...

> +		kfree(trace_profile_buf_nmi);
> +		kfree(trace_profile_buf);
> +		trace_profile_buf_nmi = NULL;
> +		trace_profile_buf = NULL;
> +	}
>  fail_buf:
> -	total_profile_count--;

since we don't decrement total_profile_count until here.

Paul.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/