From e2105ba1c262dcaa9573f11844b6e1e1ca762c3f Mon Sep 17 00:00:00 2001 From: Philip Yang Date: Mon, 15 Sep 2025 15:57:32 -0400 Subject: [PATCH] drm/amdkfd: Fix mmap write lock not release [ Upstream commit 7574f30337e19045f03126b4c51f525b84e5049e ] If mmap write lock is taken while draining retry fault, mmap write lock is not released because svm_range_restore_pages calls mmap_read_unlock then returns. This causes deadlock and system hangs later because mmap read or write lock cannot be taken. Downgrade mmap write lock to read lock if draining retry fault fix this bug. Signed-off-by: Philip Yang Reviewed-by: Harish Kasiviswanathan Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin --- drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c index 155948dc3d07..0d950a20741d 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c +++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c @@ -3036,6 +3036,8 @@ retry_write_locked: if (svms->checkpoint_ts[gpuidx] != 0) { if (amdgpu_ih_ts_after_or_equal(ts, svms->checkpoint_ts[gpuidx])) { pr_debug("draining retry fault, drop fault 0x%llx\n", addr); + if (write_locked) + mmap_write_downgrade(mm); r = -EAGAIN; goto out_unlock_svms; } else {