On Thu, 15 Oct 2026 19:22:32 +0100
Adrián Larumbe <[email protected]> wrote:
> struct panfrost_perfcnt::state should always be updated atomically, both
> in the dump ioctl and the reset sequence.
>
> Fixes: 9944dd07f3cf ("drm/panfrost: Fix races between perfcnt and reset
> sequence")
> Signed-off-by: Adrián Larumbe <[email protected]>
Reviewed-by: Boris Brezillon <[email protected]>
> ---
> drivers/gpu/drm/panfrost/panfrost_perfcnt.c | 15 +++++++--------
> 1 file changed, 7 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/gpu/drm/panfrost/panfrost_perfcnt.c
> b/drivers/gpu/drm/panfrost/panfrost_perfcnt.c
> index b26da057a1a0..d50b6cc2ecfa 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_perfcnt.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_perfcnt.c
> @@ -148,18 +148,17 @@ static int panfrost_perfcnt_dump_locked(struct
> panfrost_device *pfdev, u32 *stat
> */
> ret =
> wait_for_completion_interruptible_timeout(&pfdev->perfcnt->dump_comp,
> msecs_to_jiffies(1000));
> -
> if (!ret)
> ret = -ETIMEDOUT;
>
> - /* We need to restore perfcnt state so the next successful dump can
> relay it to UM */
> - if (ret < 0) {
> - perfcnt->state |= *state;
> - *state = 0;
> - return ret;
> - }
> -
> scoped_guard(rwsem_read, &pfdev->reset.lock) {
> + /* Restore perfcnt state so the next successful dump can relay
> it to UM */
> + if (ret < 0) {
> + perfcnt->state |= *state;
> + *state = 0;
> + return ret;
> + }
> +
> *state |= perfcnt->state;
>
> /* UM must re-enable their session before requesting new dumps.
> */
>
