From f7569ef1cf978aa87aa81b5e9bf40a77497f3685 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 cecdbcea0bb9..827507cfed7a 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c +++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c @@ -3046,6 +3046,8 @@ 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 {