linux-kernel - [RFC 03/24] drm/gpuvm: Remove bogus lock assert

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20241207161651.410556-4-robdclark@gmail.com>
Date: Sat,  7 Dec 2024 08:15:03 -0800
From: Rob Clark <robdclark@...il.com>
To: dri-devel@...ts.freedesktop.org
Cc: freedreno@...ts.freedesktop.org,
	linux-arm-msm@...r.kernel.org,
	Connor Abbott <cwabbott0@...il.com>,
	Akhil P Oommen <quic_akhilpo@...cinc.com>,
	Rob Clark <robdclark@...omium.org>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
	Maxime Ripard <mripard@...nel.org>,
	Thomas Zimmermann <tzimmermann@...e.de>,
	David Airlie <airlied@...il.com>,
	Simona Vetter <simona@...ll.ch>,
	linux-kernel@...r.kernel.org (open list)
Subject: [RFC 03/24] drm/gpuvm: Remove bogus lock assert

From: Rob Clark <robdclark@...omium.org>

If the driver is using an external mutex to synchronize vm access, it
doesn't need to hold vm->r_obj->resv.  And if the driver is already
holding obj->resv, then needing to pointlessly grab vm->r_obj->resv will
be seen by lockdep as nested locking.

Signed-off-by: Rob Clark <robdclark@...omium.org>
---
 drivers/gpu/drm/drm_gpuvm.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/drivers/gpu/drm/drm_gpuvm.c b/drivers/gpu/drm/drm_gpuvm.c
index 1e89a98caad4..c9bf18119a86 100644
--- a/drivers/gpu/drm/drm_gpuvm.c
+++ b/drivers/gpu/drm/drm_gpuvm.c
@@ -1505,9 +1505,6 @@ drm_gpuvm_bo_destroy(struct kref *kref)
 	struct drm_gem_object *obj = vm_bo->obj;
 	bool lock = !drm_gpuvm_resv_protected(gpuvm);
 
-	if (!lock)
-		drm_gpuvm_resv_assert_held(gpuvm);
-
 	drm_gpuvm_bo_list_del(vm_bo, extobj, lock);
 	drm_gpuvm_bo_list_del(vm_bo, evict, lock);
 
-- 
2.47.1