linux-kernel - Re: [RFC PATCH] drm: gpu: msm: forbid mem reclaim from reset

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Message-ID: <nbk32ecg6wgdghnsr4amj5wufk4t7pavbsuqjvc6ulychjr6jh@zyyrzqbjes4i>
Date: Tue, 3 Feb 2026 12:42:18 +0900
From: Sergey Senozhatsky <senozhatsky@...omium.org>
To: Rob Clark <robin.clark@....qualcomm.com>, Sean Paul <sean@...rly.run>
Cc: Konrad Dybcio <konradybcio@...nel.org>, 
	Akhil P Oommen <akhilpo@....qualcomm.com>, linux-arm-msm@...r.kernel.org, dri-devel@...ts.freedesktop.org, 
	freedreno@...ts.freedesktop.org, linux-kernel@...r.kernel.org, Tomasz Figa <tfiga@...omium.org>, 
	Sergey Senozhatsky <senozhatsky@...omium.org>
Subject: Re: [RFC PATCH] drm: gpu: msm: forbid mem reclaim from reset

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
> 
> INFO: task ring0:155 is blocked on a mutex likely owned by task gpu-worker:154.
> task:gpu-worker state:D stack:0 pid:154 ppid:2 flags:0x00000008
> Call trace:
> __switch_to+0x108/0x208
> schedule+0x544/0x11f0
> schedule_timeout+0x1f8/0x770
> dma_fence_default_wait+0x108/0x218
> dma_fence_wait_timeout+0x6c/0x1c0
> dma_resv_wait_timeout+0xe4/0x118
> active_purge+0x34/0x98
> drm_gem_lru_scan+0x1d0/0x388
> msm_gem_shrinker_scan+0x1cc/0x2e8
> shrink_slab+0x228/0x478
> shrink_node+0x380/0x730
> try_to_free_pages+0x204/0x510
> __alloc_pages_direct_reclaim+0x90/0x158
> __alloc_pages_slowpath+0x1d4/0x4a0
> __alloc_pages+0x9f0/0xc88
> vm_area_alloc_pages+0x17c/0x260
> __vmalloc_node_range+0x1c0/0x420
> kvmalloc_node+0xe8/0x108
> msm_gpu_crashstate_capture+0x1e4/0x280
> recover_worker+0x1c0/0x638
> kthread_worker_fn+0x150/0x2d8
> kthread+0x114/0x138
> 
> So no one can make any further progress.
> 
> Forbid recover/fault worker to enter memory reclaim (under
> gpu->lock) to address this deadlock scenario.

Gentle ping.