Re: [PATCH AUTOSEL 6.0 38/44] drm/amdgpu: Unlock bo_list_mutex after error handling

[Sasha Levin <sashal@kernel.org>]

On Mon, Nov 21, 2022 at 12:07:40PM +0100, Christian König wrote:
>Am 21.11.22 um 10:57 schrieb Michel Dänzer:
>>On 11/19/22 03:11, Sasha Levin wrote:
>>>From: Philip Yang <Philip.Yang@amd.com>
>>>
>>>[ Upstream commit 64f65135c41a75f933d3bca236417ad8e9eb75de ]
>>>
>>>Get below kernel WARNING backtrace when pressing ctrl-C to kill kfdtest
>>>application.
>>>
>>>If amdgpu_cs_parser_bos returns error after taking bo_list_mutex, as
>>>caller amdgpu_cs_ioctl will not unlock bo_list_mutex, this generates the
>>>kernel WARNING.
>>>
>>>Add unlock bo_list_mutex after amdgpu_cs_parser_bos error handling to
>>>cleanup bo_list userptr bo.
>>>
>>>  WARNING: kfdtest/2930 still has locks held!
>>>  1 lock held by kfdtest/2930:
>>>   (&list->bo_list_mutex){+.+.}-{3:3}, at: amdgpu_cs_ioctl+0xce5/0x1f10 [amdgpu]
>>>   stack backtrace:
>>>    dump_stack_lvl+0x44/0x57
>>>    get_signal+0x79f/0xd00
>>>    arch_do_signal_or_restart+0x36/0x7b0
>>>    exit_to_user_mode_prepare+0xfd/0x1b0
>>>    syscall_exit_to_user_mode+0x19/0x40
>>>    do_syscall_64+0x40/0x80
>>>
>>>Signed-off-by: Philip Yang <Philip.Yang@amd.com>
>>>Reviewed-by: Christian König <christian.koenig@amd.com>
>>>Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
>>>Signed-off-by: Sasha Levin <sashal@kernel.org>
>>>---
>>>  drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 1 +
>>>  1 file changed, 1 insertion(+)
>>>
>>>diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
>>>index b7bae833c804..9d59f83c8faa 100644
>>>--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
>>>+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
>>>@@ -655,6 +655,7 @@ static int amdgpu_cs_parser_bos(struct amdgpu_cs_parser *p,
>>>  		}
>>>  		mutex_unlock(&p->bo_list->bo_list_mutex);
>>>  	}
>>>+	mutex_unlock(&p->bo_list->bo_list_mutex);
>>>  	return r;
>>>  }
>>Looks doubtful that this is a correct backport — there's an identical mutex_unlock call just above.
>
>
>Oh, yes good point. This patch doesn't needs to be backported at all 
>because it just fixes a problem introduced in the same cycle:

Dropping it, thanks!

-- 
Thanks,
Sasha