From 8c666e6471acb1fe33b6b88d95486ed2d548d944 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Tue, 31 Oct 2017 11:55:35 +0000 Subject: [PATCH] drm: Require __GFP_NOFAIL for the legacy drm_modeset_lock_all MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit commit d18d1a5ac811d12f7ebc1129230312b5f2c50cb8 upstream. To acquire all modeset locks requires a ww_ctx to be allocated. As this is the legacy path and the allocation small, to reduce the changes required (and complex untested error handling) to the legacy drivers, we simply assume that the allocation succeeds. At present, it relies on the too-small-to-fail rule, but syzbot found that by injecting a failure here we would hit the WARN. Document that this allocation must succeed with __GFP_NOFAIL. Signed-off-by: Chris Wilson Cc: Daniel Vetter Reported-by: syzbot Signed-off-by: Daniel Vetter Reviewed-by: Ville Syrjälä Link: https://patchwork.freedesktop.org/patch/msgid/20171031115535.15166-1-chris@chris-wilson.co.uk Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/drm_modeset_lock.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/drm_modeset_lock.c b/drivers/gpu/drm/drm_modeset_lock.c index af4e906c630d..56b9f9b1c3ae 100644 --- a/drivers/gpu/drm/drm_modeset_lock.c +++ b/drivers/gpu/drm/drm_modeset_lock.c @@ -88,7 +88,7 @@ void drm_modeset_lock_all(struct drm_device *dev) struct drm_modeset_acquire_ctx *ctx; int ret; - ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); + ctx = kzalloc(sizeof(*ctx), GFP_KERNEL | __GFP_NOFAIL); if (WARN_ON(!ctx)) return; -- 2.20.1