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2dbd9c27ed
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:
|
||
|---|---|---|
| .. | ||
| Makefile | ||
| ttm_agp_backend.c | ||
| ttm_bo.c | ||
| ttm_bo_util.c | ||
| ttm_bo_vm.c | ||
| ttm_device.c | ||
| ttm_execbuf_util.c | ||
| ttm_module.c | ||
| ttm_module.h | ||
| ttm_pool.c | ||
| ttm_range_manager.c | ||
| ttm_resource.c | ||
| ttm_sys_manager.c | ||
| ttm_tt.c | ||