Affected: Linux

In the Linux kernel, the following vulnerability has been resolved:

drm/amdgpu: fix a job->pasid access race in gpu recovery

Avoid a possible UAF in GPU recovery due to a race between the sched timeout callback and the tdr work queue.

The gpu recovery function calls drm_sched_stop() and later drm_sched_start(). drm_sched_start() restarts the tdr queue which will eventually free the job. If the tdr queue frees the job before time out callback completes, the job will be freed and we'll get a UAF when accessing the pasid. Cache it early to avoid the UAF.

Example KASAN trace: [ 493.058141] BUG: KASAN: slab-use-after-free in amdgpu_device_gpu_recover+0x968/0x990 [amdgpu] [ 493.067530] Read of size 4 at addr ffff88b0ce3f794c by task kworker/u128:1/323 [ 493.074892] [ 493.076485] CPU: 9 UID: 0 PID: 323 Comm: kworker/u128:1 Tainted: G E 6.16.0-1289896.2.zuul.bf4f11df81c1410bbe901c4373305a31 #1 PREEMPT(voluntary) [ 493.076493] Tainted: [E]=UNSIGNED_MODULE [ 493.076495] Hardware name: TYAN B8021G88V2HR-2T/S8021GM2NR-2T, BIOS V1.03.B10 04/01/2019 [ 493.076500] Workqueue: amdgpu-reset-dev drm_sched_job_timedout [gpu_sched] [ 493.076512] Call Trace: [ 493.076515] <TASK> [ 493.076518] dump_stack_lvl+0x64/0x80 [ 493.076529] print_report+0xce/0x630 [ 493.076536] ? _raw_spin_lock_irqsave+0x86/0xd0 [ 493.076541] ? __pfx__raw_spin_lock_irqsave+0x10/0x10 [ 493.076545] ? amdgpu_device_gpu_recover+0x968/0x990 [amdgpu] [ 493.077253] kasan_report+0xb8/0…