From f7eae6d8d768fabd6b59779ca7da79e02c74e113 Mon Sep 17 00:00:00 2001 From: "Jonghyuk Kim(MalHyuk)" Date: Wed, 2 Sep 2026 10:27:16 +0900 Subject: [PATCH] drm/nouveau: RCU-free the scheduler-containing nouveau_sched struct nouveau_sched embeds a struct drm_gpu_scheduler (base). nouveau_sched_destroy() calls nouveau_sched_fini() (which does drm_sched_fini(&sched->base)) and then frees the object with plain kfree(sched). drm_sched_fence_get_timeline_name() returns fence->sched->name, and the scheduler fence keeps a .release callback so it is not ops-detached on signalling. A finished fence exported to userspace via drm_syncobj / sync_file therefore keeps pointing at &sched->base after nouveau_sched_destroy(), and a later get_timeline_name() -- reachable unprivileged through SYNC_IOC_FILE_INFO -- dereferences freed memory (KASAN slab-use-after-free read). Per the dma-fence lifetime contract the exporter must keep the data backing a signalled fence alive for an RCU grace period. Free the scheduler-containing object with kfree_rcu() instead of kfree(). Fixes: 5f03a507b29e ("drm/nouveau: implement 1:1 scheduler - entity relationship") Cc: stable@vger.kernel.org Signed-off-by: Jonghyuk Kim(MalHyuk) Reviewed-by: Lyude Paul Signed-off-by: Lyude Paul Link: https://patch.msgid.link/20260902012717.880724-1-malhyuk97@gmail.com --- drivers/gpu/drm/nouveau/nouveau_sched.c | 2 +- drivers/gpu/drm/nouveau/nouveau_sched.h | 1 + 2 files changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/nouveau/nouveau_sched.c b/drivers/gpu/drm/nouveau/nouveau_sched.c index 8b9f935afe09..b3f02c490ecb 100644 --- a/drivers/gpu/drm/nouveau/nouveau_sched.c +++ b/drivers/gpu/drm/nouveau/nouveau_sched.c @@ -517,7 +517,7 @@ nouveau_sched_destroy(struct nouveau_sched **psched) struct nouveau_sched *sched = *psched; nouveau_sched_fini(sched); - kfree(sched); + kfree_rcu(sched, rcu); *psched = NULL; } diff --git a/drivers/gpu/drm/nouveau/nouveau_sched.h b/drivers/gpu/drm/nouveau/nouveau_sched.h index 20cd1da8db73..51ce8dcf6285 100644 --- a/drivers/gpu/drm/nouveau/nouveau_sched.h +++ b/drivers/gpu/drm/nouveau/nouveau_sched.h @@ -98,6 +98,7 @@ void nouveau_job_free(struct nouveau_job *job); struct nouveau_sched { struct drm_gpu_scheduler base; + struct rcu_head rcu; struct drm_sched_entity entity; struct workqueue_struct *wq; struct mutex mutex;