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| author | Pavel Skripkin <paskripkin@gmail.com> | 2021-07-08 14:25:18 +0300 |
|---|---|---|
| committer | Christian König <christian.koenig@amd.com> | 2021-07-21 13:00:40 +0200 |
| commit | 2dbd9c27eda5cf83aa990266a3355960d860da71 (patch) | |
| tree | c41f9628bb77151a28a1447716a39aed1048e9ae /drivers | |
| parent | 235c3610d5f02ee91244239b43cd9ae8b4859dff (diff) | |
drm/ttm: add missing NULL checks
My local syzbot instance hit GPF in ttm_bo_release().
Unfortunately, syzbot didn't produce a reproducer for this, but I
found out possible scenario:
drm_gem_vram_create() <-- drm_gem_vram_object kzalloced
(bo embedded in this object)
ttm_bo_init()
ttm_bo_init_reserved()
ttm_resource_alloc()
man->func->alloc() <-- allocation failure
ttm_bo_put()
ttm_bo_release()
ttm_mem_io_free() <-- bo->resource == NULL passed
as second argument
*GPF*
Added NULL check inside ttm_mem_io_free() to prevent reported GPF and
make this function NULL save in future.
Same problem was in ttm_bo_move_to_lru_tail() as Christian reported.
ttm_bo_move_to_lru_tail() is called in ttm_bo_release() and mem pointer
can be NULL as well as in ttm_mem_io_free().
Fail log:
KASAN: null-ptr-deref in range [0x0000000000000020-0x0000000000000027]
...
RIP: 0010:ttm_mem_io_free+0x28/0x170 drivers/gpu/drm/ttm/ttm_bo_util.c:66
..
Call Trace:
ttm_bo_release+0xd94/0x10a0 drivers/gpu/drm/ttm/ttm_bo.c:422
kref_put include/linux/kref.h:65 [inline]
ttm_bo_put drivers/gpu/drm/ttm/ttm_bo.c:470 [inline]
ttm_bo_init_reserved+0x7cb/0x960 drivers/gpu/drm/ttm/ttm_bo.c:1050
ttm_bo_init+0x105/0x270 drivers/gpu/drm/ttm/ttm_bo.c:1074
drm_gem_vram_create+0x332/0x4c0 drivers/gpu/drm/drm_gem_vram_helper.c:228
Fixes: d3116756a710 ("drm/ttm: rename bo->mem and make it a pointer")
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210708112518.17271-1-paskripkin@gmail.com
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/gpu/drm/ttm/ttm_bo.c | 3 | ||||
| -rw-r--r-- | drivers/gpu/drm/ttm/ttm_bo_util.c | 3 |
2 files changed, 6 insertions, 0 deletions
diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c index 1b950b45cf4b..8d7fd65ccced 100644 --- a/drivers/gpu/drm/ttm/ttm_bo.c +++ b/drivers/gpu/drm/ttm/ttm_bo.c @@ -102,6 +102,9 @@ void ttm_bo_move_to_lru_tail(struct ttm_buffer_object *bo, return; } + if (!mem) + return; + man = ttm_manager_type(bdev, mem->mem_type); list_move_tail(&bo->lru, &man->lru[bo->priority]); diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c index 2f57f824e6db..763fa6f4e07d 100644 --- a/drivers/gpu/drm/ttm/ttm_bo_util.c +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c @@ -63,6 +63,9 @@ int ttm_mem_io_reserve(struct ttm_device *bdev, void ttm_mem_io_free(struct ttm_device *bdev, struct ttm_resource *mem) { + if (!mem) + return; + if (!mem->bus.offset && !mem->bus.addr) return; |