Am 03.09.2018 um 09:52 schrieb Daniel Vetter:
On Sat, Sep 01, 2018 at 01:32:54PM +0100, Chris Wilson wrote:
Quoting Jia-Ju Bai (2018-09-01 13:20:41)
The driver may sleep with holding a spinlock.
The function call paths (from bottom to top) in Linux-4.16 are:
[FUNC] kmalloc(GFP_KERNEL)
drivers/gpu/drm/drm_mm.c, 130:
kmalloc in show_leaks
drivers/gpu/drm/drm_mm.c, 913:
show_leaks in drm_mm_takedown
drivers/gpu/drm/drm_vma_manager.c, 107:
drm_mm_takedown in drm_vma_offset_manager_destroy
drivers/gpu/drm/drm_vma_manager.c, 106:
_raw_write_lock in drm_vma_offset_manager_destroy
[FUNC] kmalloc(GFP_KERNEL)
drivers/gpu/drm/drm_mm.c, 130:
kmalloc in show_leaks
drivers/gpu/drm/drm_mm.c, 913:
show_leaks in drm_mm_takedown
drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c, 71:
drm_mm_takedown in amdgpu_vram_mgr_fini
drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c, 70:
spin_lock in amdgpu_vram_mgr_fini
[FUNC] kmalloc(GFP_KERNEL)
drivers/gpu/drm/drm_mm.c, 130:
kmalloc in show_leaks
drivers/gpu/drm/drm_mm.c, 913:
show_leaks in drm_mm_takedown
drivers/gpu/drm/ttm/ttm_bo_manager.c, 128:
drm_mm_takedown in ttm_bo_man_takedown
drivers/gpu/drm/ttm/ttm_bo_manager.c, 126:
spin_lock in ttm_bo_man_takedown
To fix this bug, GFP_KERNEL is replaced with GFP_ATOMIC.
The bug are above, since those spinlocks do not protect the data and
imply use-after-free.
Adding amdgpu, since that's where the bug seems to be.
When we have use after free we might have concurrent uses as well.
I think taking the lock here is probably a good idea if you don't want
to accidentally access freed memory in show_leaks.
So Chris change sounds valid to me.
Christian.
-Daniel
_______________________________________________
dri-devel mailing list
dri-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/dri-devel
