The patch below does not apply to the 6.12-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.
Thanks, Sasha ------------------ original commit in Linus's tree ------------------ >From efe24898485c5c831e629d9c6fb9350c35cb576f Mon Sep 17 00:00:00 2001 From: Chia-I Wu <[email protected]> Date: Thu, 4 Dec 2025 09:45:45 -0800 Subject: [PATCH] drm/panthor: fix for dma-fence safe access rules Commit 506aa8b02a8d6 ("dma-fence: Add safe access helpers and document the rules") details the dma-fence safe access rules. The most common culprit is that drm_sched_fence_get_timeline_name may race with group_free_queue. Signed-off-by: Chia-I Wu <[email protected]> Reviewed-by: Boris Brezillon <[email protected]> Reviewed-by: Liviu Dudau <[email protected]> Reviewed-by: Steven Price <[email protected]> Cc: [email protected] # v6.17+ Signed-off-by: Steven Price <[email protected]> Link: https://patch.msgid.link/[email protected] --- drivers/gpu/drm/panthor/panthor_sched.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/gpu/drm/panthor/panthor_sched.c b/drivers/gpu/drm/panthor/panthor_sched.c index a17b067a04392..0f83e778d89aa 100644 --- a/drivers/gpu/drm/panthor/panthor_sched.c +++ b/drivers/gpu/drm/panthor/panthor_sched.c @@ -23,6 +23,7 @@ #include <linux/module.h> #include <linux/platform_device.h> #include <linux/pm_runtime.h> +#include <linux/rcupdate.h> #include "panthor_devfreq.h" #include "panthor_device.h" @@ -943,6 +944,9 @@ static void group_release_work(struct work_struct *work) release_work); u32 i; + /* dma-fences may still be accessing group->queues under rcu lock. */ + synchronize_rcu(); + for (i = 0; i < group->queue_count; i++) group_free_queue(group, group->queues[i]); -- 2.51.0
