drm/nouveau/ltc: protect clearing of comptags with mutex

commit f4e65efc88b64c1dbca275d42a188edccedb56c6 upstream.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/ltc/base.c b/drivers/gpu/drm/nouveau/nvkm/subdev/ltc/base.c
index 85b1464c01942013f22055be345d751636bc68cb..587c52f08d3f5803b60ca23cd3f2972d611ffed9 100644 (file)
--- a/drivers/gpu/drm/nouveau/nvkm/subdev/ltc/base.c
+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/ltc/base.c
@@ -47,8 +47,10 @@ nvkm_ltc_tags_clear(struct nvkm_ltc *ltc, u32 first, u32 count)
 
        BUG_ON((first > limit) || (limit >= ltc->num_tags));
 
+       mutex_lock(&ltc->subdev.mutex);
        ltc->func->cbc_clear(ltc, first, limit);
        ltc->func->cbc_wait(ltc);
+       mutex_unlock(&ltc->subdev.mutex);
 }
 
 int