The acquire ctx will typically be declared on the stack, which means we could have garbage values for any uninitialized field. In this case, it was triggering WARN_ON()s because 'contended' had garbage value.
Go ahead and use memset() to be more future-proof.
Reported-by: Ville Syrjälä ville.syrjala@linux.intel.com Signed-off-by: Rob Clark robdclark@gmail.com --- drivers/gpu/drm/drm_modeset_lock.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/drivers/gpu/drm/drm_modeset_lock.c b/drivers/gpu/drm/drm_modeset_lock.c index 7c2497d..4e8b244 100644 --- a/drivers/gpu/drm/drm_modeset_lock.c +++ b/drivers/gpu/drm/drm_modeset_lock.c @@ -64,6 +64,7 @@ void drm_modeset_acquire_init(struct drm_modeset_acquire_ctx *ctx, uint32_t flags) { + memset(ctx, 0, sizeof(ctx)); ww_acquire_init(&ctx->ww_ctx, &crtc_ww_class); INIT_LIST_HEAD(&ctx->locked); }
On Sat, Jun 07, 2014 at 08:29:13AM -0400, Rob Clark wrote:
The acquire ctx will typically be declared on the stack, which means we could have garbage values for any uninitialized field. In this case, it was triggering WARN_ON()s because 'contended' had garbage value.
Go ahead and use memset() to be more future-proof.
Reported-by: Ville Syrjälä ville.syrjala@linux.intel.com Signed-off-by: Rob Clark robdclark@gmail.com
drivers/gpu/drm/drm_modeset_lock.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/drivers/gpu/drm/drm_modeset_lock.c b/drivers/gpu/drm/drm_modeset_lock.c index 7c2497d..4e8b244 100644 --- a/drivers/gpu/drm/drm_modeset_lock.c +++ b/drivers/gpu/drm/drm_modeset_lock.c @@ -64,6 +64,7 @@ void drm_modeset_acquire_init(struct drm_modeset_acquire_ctx *ctx, uint32_t flags) {
- memset(ctx, 0, sizeof(ctx));
^^^ *ctx
with that fixed: Reviewed-by: Ville Syrjälä ville.syrjala@linux.intel.com Tested-by: Ville Syrjälä ville.syrjala@linux.intel.com
ww_acquire_init(&ctx->ww_ctx, &crtc_ww_class); INIT_LIST_HEAD(&ctx->locked); } -- 1.9.3
dri-devel@lists.freedesktop.org
-
Rob Clark -
Ville Syrjälä