Re: [PATCH v5 16/18] tracing/remotes: Add trace_remote cmdline options

[Vincent Donnefort <vdonnefort@google.com>]

On Wed, Aug 12, 2026 at 05:11:48PM +0000, sashiko-bot@kernel.org wrote:
> Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
> - [Medium] User-controllable command-line arguments inappropriately trigger a WARN_ON().
> --
> 
> --- Patch [16]: [PATCH v5 16/18] tracing/remotes: Add trace_remote cmdline options ---
> commit 473129b2ec6ced6d4d23093ce86b83497f7202d2
> Author: Vincent Donnefort <vdonnefort@google.com>
> 
> tracing/remotes: Add trace_remote cmdline options
> 
> This commit adds a trace_remote= boot command-line option to configure a
> trace remote upon registration. It enables configuring various options like
> buffer size, polling interval, and activating specific tracing events.
> 
> > diff --git a/kernel/trace/trace_remote.c b/kernel/trace/trace_remote.c
> > index b1c75666ab638..8764d0ed39097 100644
> > --- a/kernel/trace/trace_remote.c
> > +++ b/kernel/trace/trace_remote.c
> 
> [ ... ]
> 
> > @@ -1169,6 +1171,124 @@ static int poll_ms_show(struct seq_file *s, void *unused)
> 
> [ ... ]
> 
> > +static void trace_remote_apply_cmdline_opts(struct trace_remote *remote, char *cmdline)
> > +{
> 
> [ ... ]
> 
> > +		} else if (!strncmp(opt, "buf_size=", 9)) {
> > +			/* buf_size can only be applied if the buffer is unloaded */
> > +			if (!WARN_ON(trace_remote_loaded(remote)))
> > +				remote->trace_buffer_size = memparse(opt + 9, NULL);
> 
> [Severity: Medium]
> Should this be a pr_warn() instead of a WARN_ON()?
> 
> If the bootloader passes multiple trace_remote= parameters, and an earlier
> parameter enables events (which loads the buffer) before a later parameter
> tries to set buf_size= for the same remote, this check will fail and emit a
> warning.
> 
> Because WARN_ON() is used here, a simple typo or misordered boot command line 
> will trigger a splat and cause a kernel panic during boot on any system 
> configured with panic_on_warn.
> 
> -- 
> Sashiko AI review · https://sashiko.dev/#/patchset/20260812161340.2417322-1-vdonnefort@google.com?part=16

pr_warn() sounds good

-- 
Vincent