[PATCH 6.6.y] drm/radeon: delete radeon_fence_process in is_signaled, no deadlock

[PATCH 6.6.y] drm/radeon: delete radeon_fence_process in is_signaled, no deadlock

[Li hongliang]

From: Robert McClinton <rbmccav@gmail.com>

[ Upstream commit 9eb00b5f5697bd56baa3222c7a1426fa15bacfb5 ]

Delete the attempt to progress the queue when checking if fence is
signaled. This avoids deadlock.

dma-fence_ops::signaled can be called with the fence lock in unknown
state. For radeon, the fence lock is also the wait queue lock. This can
cause a self deadlock when signaled() tries to make forward progress on
the wait queue. But advancing the queue is unneeded because incorrectly
returning false from signaled() is perfectly acceptable.

Link: https://github.com/brave/brave-browser/issues/49182
Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/4641
Cc: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Robert McClinton <rbmccav@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 527ba26e50ec2ca2be9c7c82f3ad42998a75d0db)
Cc: stable@vger.kernel.org
[ Minor conflict resolved. ]
Signed-off-by: Li hongliang <1468888505@139.com>
---
 drivers/gpu/drm/radeon/radeon_fence.c | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/drivers/gpu/drm/radeon/radeon_fence.c b/drivers/gpu/drm/radeon/radeon_fence.c
index 6d5e828fa39e..1462837fda5a 100644
--- a/drivers/gpu/drm/radeon/radeon_fence.c
+++ b/drivers/gpu/drm/radeon/radeon_fence.c
@@ -362,14 +362,6 @@ static bool radeon_fence_is_signaled(struct dma_fence *f)
 		return true;
 	}
 
-	if (down_read_trylock(&rdev->exclusive_lock)) {
-		radeon_fence_process(rdev, ring);
-		up_read(&rdev->exclusive_lock);
-
-		if (atomic64_read(&rdev->fence_drv[ring].last_seq) >= seq) {
-			return true;
-		}
-	}
 	return false;
 }
 
-- 
2.34.1

Patch "drm/radeon: delete radeon_fence_process in is_signaled, no deadlock" has been added to the 6.6-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    drm/radeon: delete radeon_fence_process in is_signaled, no deadlock

to the 6.6-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     drm-radeon-delete-radeon_fence_process-in-is_signaled-no-deadlock.patch
and it can be found in the queue-6.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


From 1468888505@139.com Mon Feb  2 08:58:36 2026
From: Li hongliang <1468888505@139.com>
Date: Mon,  2 Feb 2026 15:58:31 +0800
Subject: drm/radeon: delete radeon_fence_process in is_signaled, no deadlock
To: gregkh@linuxfoundation.org, stable@vger.kernel.org, rbmccav@gmail.com
Cc: patches@lists.linux.dev, linux-kernel@vger.kernel.org, alexander.deucher@amd.com, christian.koenig@amd.com, Xinhui.Pan@amd.com, airlied@gmail.com, daniel@ffwll.ch, amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org
Message-ID: <20260202075831.947537-1-1468888505@139.com>

From: Robert McClinton <rbmccav@gmail.com>

[ Upstream commit 9eb00b5f5697bd56baa3222c7a1426fa15bacfb5 ]

Delete the attempt to progress the queue when checking if fence is
signaled. This avoids deadlock.

dma-fence_ops::signaled can be called with the fence lock in unknown
state. For radeon, the fence lock is also the wait queue lock. This can
cause a self deadlock when signaled() tries to make forward progress on
the wait queue. But advancing the queue is unneeded because incorrectly
returning false from signaled() is perfectly acceptable.

Link: https://github.com/brave/brave-browser/issues/49182
Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/4641
Cc: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Robert McClinton <rbmccav@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 527ba26e50ec2ca2be9c7c82f3ad42998a75d0db)
Cc: stable@vger.kernel.org
[ Minor conflict resolved. ]
Signed-off-by: Li hongliang <1468888505@139.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/gpu/drm/radeon/radeon_fence.c |    8 --------
 1 file changed, 8 deletions(-)

--- a/drivers/gpu/drm/radeon/radeon_fence.c
+++ b/drivers/gpu/drm/radeon/radeon_fence.c
@@ -362,14 +362,6 @@ static bool radeon_fence_is_signaled(str
 		return true;
 	}
 
-	if (down_read_trylock(&rdev->exclusive_lock)) {
-		radeon_fence_process(rdev, ring);
-		up_read(&rdev->exclusive_lock);
-
-		if (atomic64_read(&rdev->fence_drv[ring].last_seq) >= seq) {
-			return true;
-		}
-	}
 	return false;
 }
 


Patches currently in stable-queue which might be from 1468888505@139.com are

queue-6.6/drm-radeon-delete-radeon_fence_process-in-is_signaled-no-deadlock.patch
queue-6.6/ksmbd-fix-race-condition-in-rpc-handle-list-access.patch
queue-6.6/wifi-ath11k-add-srng-lock-for-ath11k_hal_srng_-in-monitor-mode.patch
queue-6.6/drm-amdgpu-replace-mutex-with-spinlock-for-rlcg-register-access-to-avoid-priority-inversion-in-sriov.patch