[PATCH 6.6 219/396] drm/i915: Check before removing mm notifier

Greg Kroah-Hartman
2024-04-01T16:46:47Z

From: Nirmoy Das <nirmoy.das@intel.com>

commit 01bb1ae35006e473138c90711bad1a6b614a1823 upstream.

Error in mmu_interval_notifier_insert() can leave a NULL
notifier.mm pointer. Catch that and return early.

Fixes: ed29c2691188 ("drm/i915: Fix userptr so we do not have to worry about obj->mm.lock, v7.")
Cc: <stable@vger.kernel.org> # v5.13+
[tursulin: Added Fixes and cc stable.]
Cc: Andi Shyti <andi.shyti@linux.intel.com>
Cc: Shawn Lee <shawn.c.lee@intel.com>
Signed-off-by: Nirmoy Das <nirmoy.das@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240219125047.28906-1-nirmoy.das@intel.com
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
(cherry picked from commit db7bbd13f08774cde0332c705f042e327fe21e73)
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/gpu/drm/i915/gem/i915_gem_userptr.c | 3 +++
1 file changed, 3 insertions(+)

--- a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
@@ -379,6 +379,9 @@ i915_gem_userptr_release(struct drm_i915
{
GEM_WARN_ON(obj->userptr.page_ref);

+ if (!obj->userptr.notifier.mm)
+ return;
+
mmu_interval_notifier_remove(&obj->userptr.notifier);
obj->userptr.notifier.mm = NULL;
}