----- Original Message -----
From: "Dan Carpenter" dan.carpenter@oracle.com To: bskeggs@redhat.com Cc: dri-devel@lists.freedesktop.org Sent: Tuesday, 12 November, 2013 7:54:33 PM Subject: re: drm/nouveau/pwr: initial implementation
Hello Ben Skeggs,
Hey,
The patch ff4b42c7532e: "drm/nouveau/pwr: initial implementation" from Oct 15, 2013, leads to the following Smatch warning: "drivers/gpu/drm/nouveau/core/subdev/pwr/base.c:48 nouveau_pwr_send() warn: 'mutex:&subdev->mutex' is sometimes locked here and sometimes unlocked."
drivers/gpu/drm/nouveau/core/subdev/pwr/base.c 35 /* we currently only support a single process at a time waiting 36 * on a synchronous reply, take the PPWR mutex and tell the 37 * receive handler what we're waiting for 38 */ 39 if (reply) { 40 mutex_lock(&subdev->mutex); 41 ppwr->recv.message = message; 42 ppwr->recv.process = process; 43 } 44 45 /* wait for a free slot in the fifo */ 46 addr = nv_rd32(ppwr, 0x10a4a0); 47 if (!nv_wait_ne(ppwr, 0x10a4b0, 0xffffffff, addr ^ 8)) 48 return -EBUSY;
Should we have an if (reply) mutex_unlock(&subdev->mutex) before the return?
Yes, we should. It's been reported, no fix pushed to Linus' tree yet as the path that can hit it has been hardcoded as disabled for this release.
Thanks, Ben.
49regards, dan carpenter