From: Philip Yang Philip.Yang@amd.com

[ Upstream commit fa582c6f3684ac0098a9d02ddf0ed52a02b37127 ]

MMU notifier callback may pass in mm with mm->mm_users==0 when process is exiting, use mmget_no_zero to avoid accessing invalid mm in deferred list work after mm is gone.

Signed-off-by: Philip Yang Philip.Yang@amd.com Reviewed-by: Felix Kuehling Felix.Kuehling@amd.com Signed-off-by: Alex Deucher alexander.deucher@amd.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 3 +++ 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c index 830809b694dd..74e6f613be02 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c +++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c @@ -2181,6 +2181,8 @@ svm_range_cpu_invalidate_pagetables(struct mmu_interval_notifier *mni,

if (range->event == MMU_NOTIFY_RELEASE) return true; + if (!mmget_not_zero(mni->mm)) + return true;

start = mni->interval_tree.start; last = mni->interval_tree.last; @@ -2207,6 +2209,7 @@ svm_range_cpu_invalidate_pagetables(struct mmu_interval_notifier *mni, }

svm_range_unlock(prange); + mmput(mni->mm);

return true; }