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From: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>
To: maarten.lankhorst@linux.intel.com, mripard@kernel.org,
	tzimmermann@suse.de, airlied@linux.ie, daniel@ffwll.ch,
	sumit.semwal@linaro.org, christian.koenig@amd.com,
	axboe@kernel.dk, oleg@redhat.com, tglx@linutronix.de,
	dvyukov@google.com, walter-zh.wu@mediatek.com
Cc: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>,
	dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
	intel-gfx@lists.freedesktop.org, linux-media@vger.kernel.org,
	linaro-mm-sig@lists.linaro.org, skhan@linuxfoundation.org,
	gregkh@linuxfoundation.org,
	linux-kernel-mentees@lists.linuxfoundation.org
Subject: [Intel-gfx] [PATCH v3 2/9] drm: hold master_lookup_lock when releasing a drm_file's master
Date: Wed, 18 Aug 2021 15:38:17 +0800	[thread overview]
Message-ID: <20210818073824.1560124-3-desmondcheongzx@gmail.com> (raw)
In-Reply-To: <20210818073824.1560124-1-desmondcheongzx@gmail.com>

When drm_file.master changes value, the corresponding
drm_device.master_lookup_lock should be held.

In drm_master_release, a call to drm_master_put sets the
file_priv->master to NULL, so we protect this section with
drm_device.master_lookup_lock.

Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>
---
 drivers/gpu/drm/drm_auth.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_auth.c b/drivers/gpu/drm/drm_auth.c
index 8efb58aa7d95..8c0e0dba1611 100644
--- a/drivers/gpu/drm/drm_auth.c
+++ b/drivers/gpu/drm/drm_auth.c
@@ -373,8 +373,11 @@ void drm_master_release(struct drm_file *file_priv)
 	}
 
 	/* drop the master reference held by the file priv */
-	if (file_priv->master)
+	if (file_priv->master) {
+		spin_lock(&dev->master_lookup_lock);
 		drm_master_put(&file_priv->master);
+		spin_unlock(&dev->master_lookup_lock);
+	}
 	mutex_unlock(&dev->master_mutex);
 }
 
-- 
2.25.1


  parent reply	other threads:[~2021-08-18 11:26 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-18  7:38 [Intel-gfx] [PATCH v3 0/9] drm, kernel: update locking for DRM Desmond Cheong Zhi Xi
2021-08-18  7:38 ` [Intel-gfx] [PATCH v3 1/9] drm: move master_lookup_lock into drm_device Desmond Cheong Zhi Xi
2021-08-18  7:38 ` Desmond Cheong Zhi Xi [this message]
2021-08-18 10:05   ` [Intel-gfx] [PATCH v3 2/9] drm: hold master_lookup_lock when releasing a drm_file's master Daniel Vetter
2021-08-18 14:50     ` Desmond Cheong Zhi Xi
2021-08-18  7:38 ` [Intel-gfx] [PATCH v3 3/9] drm: check for null master in drm_is_current_master_locked Desmond Cheong Zhi Xi
2021-08-18 10:04   ` Daniel Vetter
2021-08-18  7:38 ` [Intel-gfx] [PATCH v3 4/9] drm: fix potential null ptr dereferences in drm_{auth, ioctl} Desmond Cheong Zhi Xi
2021-08-18 10:11   ` Daniel Vetter
2021-08-18 15:37     ` Desmond Cheong Zhi Xi
2021-08-18 16:33       ` Daniel Vetter
2021-08-19  5:31         ` Desmond Cheong Zhi Xi
2021-08-18  7:38 ` [Intel-gfx] [PATCH v3 5/9] drm: protect magic_map, unique{_len} with master_lookup_lock Desmond Cheong Zhi Xi
2021-08-18 10:43   ` Daniel Vetter
2021-08-18  7:38 ` [Intel-gfx] [PATCH v3 6/9] drm: convert drm_device.master_mutex into a rwsem Desmond Cheong Zhi Xi
2021-08-18  7:38 ` [Intel-gfx] [PATCH v3 7/9] drm: update global mutex lock in the ioctl handler Desmond Cheong Zhi Xi
2021-08-18 11:02   ` Daniel Vetter
2021-08-19 10:52     ` Desmond Cheong Zhi Xi
2021-08-19 11:21       ` Daniel Vetter
2021-08-18  7:38 ` [Intel-gfx] [PATCH v3 8/9] kernel: export task_work_add Desmond Cheong Zhi Xi
2021-08-18 11:06   ` Daniel Vetter
2021-08-19  9:26   ` Christoph Hellwig
2021-08-19  9:40     ` Desmond Cheong Zhi Xi
2021-08-18  7:38 ` [Intel-gfx] [PATCH v3 9/9] drm: avoid races with modesetting rights Desmond Cheong Zhi Xi
2021-08-18 13:53 ` [Intel-gfx] ✗ Fi.CI.BAT: failure for drm, kernel: update locking for DRM Patchwork
2021-08-19 11:09 ` [Intel-gfx] ✗ Fi.CI.BUILD: failure for drm, kernel: update locking for DRM (rev2) Patchwork

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