On (26/03/27 09:08), Rob Clark wrote: > On Thu, Mar 26, 2026 at 5:18 PM Akhil P Oommen <[email protected]> > wrote: > > > > On 3/26/2026 7:24 AM, Sergey Senozhatsky wrote: > > > On (26/01/27 16:33), Sergey Senozhatsky wrote: > > >> We sometimes get into a situtation where GPU hangcheck fails to > > >> recover GPU: > > >> > > >> [..] > > >> msm_dpu ae01000.display-controller: [drm:hangcheck_handler] *ERROR* > > >> (IPv4: 1): hangcheck detected gpu lockup rb 0! > > >> msm_dpu ae01000.display-controller: [drm:hangcheck_handler] *ERROR* > > >> (IPv4: 1): completed fence: 7840161 > > >> msm_dpu ae01000.display-controller: [drm:hangcheck_handler] *ERROR* > > >> (IPv4: 1): submitted fence: 7840162 > > >> msm_dpu ae01000.display-controller: [drm:hangcheck_handler] *ERROR* > > >> (IPv4: 1): hangcheck detected gpu lockup rb 0! > > >> msm_dpu ae01000.display-controller: [drm:hangcheck_handler] *ERROR* > > >> (IPv4: 1): completed fence: 7840162 > > >> msm_dpu ae01000.display-controller: [drm:hangcheck_handler] *ERROR* > > >> (IPv4: 1): submitted fence: 7840163 > > >> [..] > > >> > > >> The problem is that msm_job worker is blocked on gpu->lock > > >> > > >> INFO: task ring0:155 blocked for more than 122 seconds. > > >> Not tainted 6.6.99-08727-gaac38b365d2c #1 > > >> task:ring0 state:D stack:0 pid:155 ppid:2 flags:0x00000008 > > >> Call trace: > > >> __switch_to+0x108/0x208 > > >> schedule+0x544/0x11f0 > > >> schedule_preempt_disabled+0x30/0x50 > > >> __mutex_lock_common+0x410/0x850 > > >> __mutex_lock_slowpath+0x28/0x40 > > >> mutex_lock+0x5c/0x90 > > >> msm_job_run+0x9c/0x140 > > >> drm_sched_main+0x514/0x938 > > >> kthread+0x114/0x138 > > >> ret_from_fork+0x10/0x20 > > >> > > >> which is owned by recover worker, which is waiting for DMA fences > > >> from a memory reclaim path, under the very same gpu->lock > > > > I am still thinking if there is a better way to handle this. Btw, Rob > > had a few fixes related to this area recently. Do you think those would > > help in this scenario? > > For some reason I was thinking we used GFP_ATOMIC or similar in the > gpu snapshot path.. but we don't :-( > > It does look like we handle allocation failures. So this is probably > a better option than fixing up GFP flags everywhere. > > Reviewed-by: Rob Clark <[email protected]>
Thanks! > > (and apologies for overlooking this patch earlier) No worries.
