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From: Zheyu Ma <zheyuma97@gmail.com>
To: christian.koenig@amd.com, ray.huang@amd.com, airlied@linux.ie,
	daniel@ffwll.ch
Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
	Zheyu Ma <zheyuma97@gmail.com>
Subject: [PATCH] drm/ttm: add a check against null pointer dereference
Date: Wed, 14 Jul 2021 14:54:19 +0000	[thread overview]
Message-ID: <1626274459-8148-1-git-send-email-zheyuma97@gmail.com> (raw)

When calling ttm_range_man_fini(), 'man' may be uninitialized, which may
cause a null pointer dereference bug.

Fix this by checking if it is a null pointer.

This log reveals it:

[    7.902580 ] BUG: kernel NULL pointer dereference, address: 0000000000000058
[    7.905721 ] RIP: 0010:ttm_range_man_fini+0x40/0x160
[    7.911826 ] Call Trace:
[    7.911826 ]  radeon_ttm_fini+0x167/0x210
[    7.911826 ]  radeon_bo_fini+0x15/0x40
[    7.913767 ]  rs400_fini+0x55/0x80
[    7.914358 ]  radeon_device_fini+0x3c/0x140
[    7.914358 ]  radeon_driver_unload_kms+0x5c/0xe0
[    7.914358 ]  radeon_driver_load_kms+0x13a/0x200
[    7.914358 ]  ? radeon_driver_unload_kms+0xe0/0xe0
[    7.914358 ]  drm_dev_register+0x1db/0x290
[    7.914358 ]  radeon_pci_probe+0x16a/0x230
[    7.914358 ]  local_pci_probe+0x4a/0xb0

Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
---
 drivers/gpu/drm/ttm/ttm_range_manager.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/ttm/ttm_range_manager.c b/drivers/gpu/drm/ttm/ttm_range_manager.c
index 03395386e8a7..f4b08a8705b3 100644
--- a/drivers/gpu/drm/ttm/ttm_range_manager.c
+++ b/drivers/gpu/drm/ttm/ttm_range_manager.c
@@ -181,6 +181,9 @@ int ttm_range_man_fini(struct ttm_device *bdev,
 	struct drm_mm *mm = &rman->mm;
 	int ret;
 
+	if (!man)
+		return 0;
+
 	ttm_resource_manager_set_used(man, false);
 
 	ret = ttm_resource_manager_evict_all(bdev, man);
-- 
2.17.6


WARNING: multiple messages have this Message-ID (diff)
From: Zheyu Ma <zheyuma97@gmail.com>
To: christian.koenig@amd.com, ray.huang@amd.com, airlied@linux.ie,
	daniel@ffwll.ch
Cc: Zheyu Ma <zheyuma97@gmail.com>,
	linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org
Subject: [PATCH] drm/ttm: add a check against null pointer dereference
Date: Wed, 14 Jul 2021 14:54:19 +0000	[thread overview]
Message-ID: <1626274459-8148-1-git-send-email-zheyuma97@gmail.com> (raw)

When calling ttm_range_man_fini(), 'man' may be uninitialized, which may
cause a null pointer dereference bug.

Fix this by checking if it is a null pointer.

This log reveals it:

[    7.902580 ] BUG: kernel NULL pointer dereference, address: 0000000000000058
[    7.905721 ] RIP: 0010:ttm_range_man_fini+0x40/0x160
[    7.911826 ] Call Trace:
[    7.911826 ]  radeon_ttm_fini+0x167/0x210
[    7.911826 ]  radeon_bo_fini+0x15/0x40
[    7.913767 ]  rs400_fini+0x55/0x80
[    7.914358 ]  radeon_device_fini+0x3c/0x140
[    7.914358 ]  radeon_driver_unload_kms+0x5c/0xe0
[    7.914358 ]  radeon_driver_load_kms+0x13a/0x200
[    7.914358 ]  ? radeon_driver_unload_kms+0xe0/0xe0
[    7.914358 ]  drm_dev_register+0x1db/0x290
[    7.914358 ]  radeon_pci_probe+0x16a/0x230
[    7.914358 ]  local_pci_probe+0x4a/0xb0

Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
---
 drivers/gpu/drm/ttm/ttm_range_manager.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/ttm/ttm_range_manager.c b/drivers/gpu/drm/ttm/ttm_range_manager.c
index 03395386e8a7..f4b08a8705b3 100644
--- a/drivers/gpu/drm/ttm/ttm_range_manager.c
+++ b/drivers/gpu/drm/ttm/ttm_range_manager.c
@@ -181,6 +181,9 @@ int ttm_range_man_fini(struct ttm_device *bdev,
 	struct drm_mm *mm = &rman->mm;
 	int ret;
 
+	if (!man)
+		return 0;
+
 	ttm_resource_manager_set_used(man, false);
 
 	ret = ttm_resource_manager_evict_all(bdev, man);
-- 
2.17.6


             reply	other threads:[~2021-07-14 14:54 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-14 14:54 Zheyu Ma [this message]
2021-07-14 14:54 ` [PATCH] drm/ttm: add a check against null pointer dereference Zheyu Ma
2021-07-14 15:06 ` Christian König
2021-07-14 15:06   ` Christian König

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