Re: [PATCH] drm/i915: check before removing mm notifier

[Nirmoy Das]

Merged it to drm-intel-gt-next with s/check/Check

On 2/19/2024 1:50 PM, Nirmoy Das wrote:

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

Cc: Andi Shyti <andi.sh...@linux.intel.com>
Cc: Shawn Lee <shawn.c....@intel.com>
Signed-off-by: Nirmoy Das <nirmoy....@intel.com>
---
  drivers/gpu/drm/i915/gem/i915_gem_userptr.c | 3 +++
  1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c 
b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
index 0e21ce9d3e5a..61abfb505766 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
@@ -349,6 +349,9 @@ i915_gem_userptr_release(struct drm_i915_gem_object *obj)
  {
        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;
  }