PR/60926 CVS commit: src/sys/external/bsd/drm2/linux

["Taylor R Campbell" <riastradh%netbsd.org@localhost>]

The following reply was made to PR kern/60926; it has been noted by GNATS.

From: "Taylor R Campbell" <riastradh%netbsd.org@localhost>
To: gnats-bugs%gnats.NetBSD.org@localhost
Cc: 
Subject: PR/60926 CVS commit: src/sys/external/bsd/drm2/linux
Date: Sat, 7 Nov 2026 14:05:03 +0000

 Module Name:	src
 Committed By:	riastradh
 Date:		Sat Nov  7 14:05:02 UTC 2026
 
 Modified Files:
 	src/sys/external/bsd/drm2/linux: linux_ww_mutex.c
 
 Log Message:
 linux ww_mutex: Nix another assertion that trips in sketchy path.
 
 Under the premise (explained in the comment above) that it is
 legitimate for the upstream Linux code to do ww_mutex_trylock on a
 mutex already held by the current thread, we can't assert
 
 	mutex->wwm_state != WW_WANTOWN ||
 	    mutex->wwm_u.ctx->wwx_owner != curlwp
 
 any more than we can assert
 
 	mutex->wwm_state != WW_CTX ||
 	    mutex->wwm_u.ctx->wwx_owner != curlwp
 
 because if the latter condition is possible, then any concurrent
 thread tries to acquire the mutex a moment before we test that
 condition will turn it into the former condition, i.e., transition to
 mutex->wwm_state = WW_WANTOWN with mutex->wwm_u.ctx->wwx_owner =
 curlwp.
 
 PR kern/60926: amdgpu triggers assert in ww_mutex, disabling makes it
 mostly stable (raven ridge)
 
 
 To generate a diff of this commit:
 cvs rdiff -u -r1.17 -r1.18 src/sys/external/bsd/drm2/linux/linux_ww_mutex.c
 
 Please note that diffs are not public domain; they are subject to the
 copyright notices on the relevant files.