Re: [PATCH 1/2] remoteproc: core: Attach rproc asynchronously in rproc_add() path

Stephan Gerhold
2026-04-10T14:28:14Z

+Cc Bartosz, Dmitry

On Thu, Apr 09, 2026 at 01:46:21AM -0700, Jingyi Wang wrote:
> For rproc with state RPROC_DETACHED and auto_boot enabled, the attach
> callback will be called in the rproc_add()->rproc_trigger_auto_boot()->
> rproc_boot() path, the failure in this path will cause the rproc_add()
> fail and the resource release, which will cause issue like rproc recovery
> or falling back to firmware load fail. Add attach_work for rproc and call
> it asynchronously in rproc_add() path like what rproc_start() do.
>
> Signed-off-by: Jingyi Wang <jingyi.wang@oss.qualcomm.com>
> ---
> drivers/remoteproc/remoteproc_core.c | 20 ++++++++++++--------
> include/linux/remoteproc.h | 1 +
> 2 files changed, 13 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
> index b087ed21858a..f02db1113fae 100644
> --- a/drivers/remoteproc/remoteproc_core.c
> +++ b/drivers/remoteproc/remoteproc_core.c
> @@ -1673,18 +1673,21 @@ static void rproc_auto_boot_callback(const struct firmware *fw, void *context)
> release_firmware(fw);
> }
>
> +static void rproc_attach_work(struct work_struct *work)
> +{
> + struct rproc *rproc = container_of(work, struct rproc, attach_work);
> +
> + rproc_boot(rproc);
> +}
> +
> static int rproc_trigger_auto_boot(struct rproc *rproc)
> {
> int ret;
>
> - /*
> - * Since the remote processor is in a detached state, it has already
> - * been booted by another entity. As such there is no point in waiting
> - * for a firmware image to be loaded, we can simply initiate the process
> - * of attaching to it immediately.
> - */
> - if (rproc->state == RPROC_DETACHED)
> - return rproc_boot(rproc);
> + if (rproc->state == RPROC_DETACHED) {
> + schedule_work(&rproc->attach_work);
> + return 0;
> + }

I think the change itself is reasonable to make "auto-attach" behavior
consistent with "auto-boot". The commit message is a bit misleading
though:

- You're really doing two separate functional changes here:

(1) Ignore the return value of rproc_boot() during auto-boot attach,
to keep the remoteproc registered and available in sysfs even if
attaching fails.
(2) Run the rproc_boot() in the background using schedule_work().
[To improve boot performance? To work around some locking issues?]

- The actual issue you are seeing sounds like a use-after-free in the
remoteproc core error cleanup path. I think this one is still
present, we should really have a call to
cancel_work_sync(&rproc->crash_handler) as Dmitry wrote in the
previous discussion [1].

Thanks,
Stephan

[1]: https://lore.kernel.org/all/ce24a2sgg4b6wymoxwgl2ve6np2nxn2wuxfqxfpmvqqrpvgouf@xihd6ziqwu4m/