Am 10.09.2018 um 15:05 schrieb Tom St Denis:
On 2018-09-10 9:04 a.m., Christian König wrote:
Hi Tom,
I'm talking about adding new printks to figure out what the heck is going wrong here.
Thanks, Christian.
Hi Christian,
Sure, if you want to send me a simple patch that adds more printk I'll gladly give it a try (doubly so since my workstation depends on our staging tree to work properly...).
Just add a printk to ttm_bo_bulk_move_helper to print pos->first and pos->last.
And another one to amdgpu_bo_destroy to printk the value of tbo.
Christian.
Tom
Am 10.09.2018 um 14:59 schrieb Tom St Denis:
Hi Christian,
Are you adding new traces or turning on existing ones? Would you like me to try them out in my setup?
Tom
On 2018-09-10 8:49 a.m., Christian König wrote:
Am 10.09.2018 um 14:05 schrieb Huang Rui:
On Mon, Sep 10, 2018 at 05:25:48PM +0800, Koenig, Christian wrote:
Am 10.09.2018 um 11:23 schrieb Huang Rui: > On Mon, Sep 10, 2018 at 11:00:04AM +0200, Christian König wrote: >> Hi Ray, >> >> well those patches doesn't make sense, the pointer is only >> local to >> the function. > You're right. > I narrowed it with gdb dump from ttm_bo_bulk_move_lru_tail+0x2b, > the > use-after-free should be in below codes: > > man = &bulk->tt[i].first->bdev->man[TTM_PL_TT]; > ttm_bo_bulk_move_helper(&bulk->tt[i], &man->lru[i], false); > > Is there a case, when orignal bo is destroyed in the bulk pos, > but it > doesn't update pos->first pointer, then we still use it during > the bulk > moving? Only when a per VM BO is freed or the VM destroyed.
The first case should now be handled by "drm/amdgpu: set bulk_moveable to false when a per VM is released" and when we use a destroyed VM we would see other problems as well.
If a VM instance is teared down, all BOs which belong that VM should be removed from LRU. But how can we submit cmd based on a destroyed VM? You know, we do the bulk move at last step of submission.
Well exactly that's the point this can't happen :)
Otherwise we would crash because of using freed up memory much earlier in the command submission.
The best idea I have to track this down further is to add some trace_printk in ttm_bo_bulk_move_helper and amdgpu_bo_destroy and see why and when we are actually using a destroyed BO.
Christian.
Thanks, Ray
BTW: Just pushed this commit to the repository, should show up any second.
Christian.
> Thanks, > Ray > >> Regards, >> Christian. >> >> Am 10.09.2018 um 10:57 schrieb Huang Rui: >>> It avoids to be refered again after freed. >>> >>> Signed-off-by: Huang Rui ray.huang@amd.com >>> Cc: Christian König christian.koenig@amd.com >>> Cc: Tom StDenis Tom.StDenis@amd.com >>> --- >>> drivers/gpu/drm/ttm/ttm_bo.c | 1 + >>> 1 file changed, 1 insertion(+) >>> >>> diff --git a/drivers/gpu/drm/ttm/ttm_bo.c >>> b/drivers/gpu/drm/ttm/ttm_bo.c >>> index 138c989..d3ef5f8 100644 >>> --- a/drivers/gpu/drm/ttm/ttm_bo.c >>> +++ b/drivers/gpu/drm/ttm/ttm_bo.c >>> @@ -54,6 +54,7 @@ static struct attribute ttm_bo_count = { >>> static void ttm_bo_default_destroy(struct ttm_buffer_object >>> *bo) >>> { >>> kfree(bo); >>> + bo = NULL; >>> } >>> static inline int ttm_mem_type_from_place(const struct >>> ttm_place *place, >> _______________________________________________ >> amd-gfx mailing list >> amd-gfx@lists.freedesktop.org >> https://lists.freedesktop.org/mailman/listinfo/amd-gfx
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