drm/i915: Fix off-by-one in reporting hanging process

ickle · rodrigovivi · commit 65f26e978d7c · 2019-03-18T13:59:30.000-07:00
ffs() is 1-indexed, but we want to use it as an index into an array, so use __ffs() instead. Fixes: eb8d0f5 ("drm/i915: Remove GPU reset dependence on struct_mutex") Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com> Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190315163933.19352-1-chris@chris-wilson.co.uk (cherry picked from commit 9073e5b) Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c
@@ -1721,7 +1721,7 @@ error_msg(struct i915_gpu_state *error, unsigned long engines, const char *msg)
 			i915_error_generate_code(error, engines));
 	if (engines) {
 		/* Just show the first executing process, more is confusing */
-		i = ffs(engines);
+		i = __ffs(engines);
 		len += scnprintf(error->error_msg + len,
 				 sizeof(error->error_msg) - len,
 				 ", in %s [%d]",
