[...] > > Could this be due to amdgpu setting sched->ready when the rings are > > finished initializing from long ago rather than when the scheduler has > > been armed? > > Yes and that is absolutely intentional. > > Either the driver is not done with it's resume yet, or it has already > started it's suspend handler. So the scheduler backends are not started > and so the ready flag is false. > > But some userspace application still tries to submit work. > > If we would now wait for this work to finish we would deadlock, so > crashing on the NULL pointer deref is actually the less worse outcome. > > Christian. Hi Christian, Today in the morning, when I woke up my workstation, I was greeted with a black screen, on which I still could move my mouse pointer. The OOPS happens at resume time, not at suspend time: ... Jän 10 07:58:14 ryzen9 kernel: [drm] scheduler comp_1.2.1 is not ready, skipping Jän 10 07:58:14 ryzen9 kernel: [drm] scheduler comp_1.3.1 is not ready, skipping Jän 10 07:58:14 ryzen9 kernel: BUG: kernel NULL pointer dereference, address: 0000000000000008 Jän 10 07:58:14 ryzen9 kernel: #PF: supervisor read access in kernel mode Jän 10 07:58:14 ryzen9 kernel: #PF: error_code(0x0000) - not-present page Jän 10 07:58:14 ryzen9 kernel: PGD 0 P4D 0 Jän 10 07:58:14 ryzen9 kernel: Oops: Oops: 0000 [#2] PREEMPT SMP NOPTI Jän 10 07:58:14 ryzen9 kernel: CPU: 2 UID: 1001 PID: 4961 Comm: chrome:cs0 Tainted: G D OE 6.12.5-200.fc41.x86_64 #1 Jän 10 07:58:14 ryzen9 kernel: Tainted: [D]=DIE, [O]=OOT_MODULE, [E]=UNSIGNED_MODULE Jän 10 07:58:14 ryzen9 kernel: Hardware name: Micro-Star International Co., Ltd. MS-7A38/B450M PRO-VDH MAX (MS-7A38), BIOS B.B0 02/03/2021 Jän 10 07:58:14 ryzen9 kernel: RIP: 0010:drm_sched_job_arm+0x23/0x60 [gpu_sched] Jän 10 07:58:14 ryzen9 kernel: Code: 90 90 90 90 90 90 90 f3 0f 1e fa 0f 1f 44 00 00 55 53 48 8b 6f 60 48 85 ed 74 3f 48 89 fb 48 89 ef e8 e1 38 00 00 48 8b 45 10 <48> 8b 50 08 48 89 53 18 8b 45 24 89 43 5c b8 01 00 00 00 f0 48 0f Jän 10 07:58:14 ryzen9 kernel: RSP: 0018:ffffa52510cf7758 EFLAGS: 00010206 ... Can we conclude that "the driver is not yet ready with it's resume"? Can you point me to where I could add instrumentation code to dig deeper? Thanks, Philipp
