Am 09.06.21 um 22:00 schrieb Ondrej Zary:
On Wednesday 09 June 2021 11:21:05 Christian König wrote:
Am 09.06.21 um 09:10 schrieb Ondrej Zary:
On Wednesday 09 June 2021, Christian König wrote:
Am 09.06.21 um 08:57 schrieb Ondrej Zary:
[SNIP]
Thanks for the heads up. So the problem with my patch is already fixed,
isn't it?
The NULL pointer dereference in nouveau_bo_wr16 introduced in
141b15e59175aa174ca1f7596188bd15a7ca17ba was fixed by
aea656b0d05ec5b8ed5beb2f94c4dd42ea834e9d.
That's the bug I hit when bisecting the original problem:
NULL pointer dereference in nouveau_bo_sync_for_device
It's caused by:
# first bad commit: [e34b8feeaa4b65725b25f49c9b08a0f8707e8e86] drm/ttm: merge ttm_dma_tt back into ttm_tt
Good that I've asked :)
Ok that's a bit strange. e34b8feeaa4b65725b25f49c9b08a0f8707e8e86 was
created mostly automated.
Do you have the original backtrace of that NULL pointer deref once more?
The original backtrace is here: https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flkml.org%2Flkml%2F2021%2F6%2F5%2F350&data=04%7C01%7Cchristian.koenig%40amd.com%7C4309ff021d5e4cbe948b08d92b813106%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637588657045383056%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=t70c9ktzPJzDaEAcO4wpQMv3TUo5b53cUy66AkLeVwE%3D&reserved=0
And the problem is that ttm_dma->dma_address is NULL, right? Mhm, I
don't see how that can happen since nouveau is using ttm_sg_tt_init().
Apart from that what nouveau does here is rather questionable since you
need a coherent architecture for most things anyway, but that's not what
we are trying to fix here.
Can you try to narrow down if ttm_sg_tt_init is called before calling
this function for the tt object in question?
ttm_sg_tt_init is not called:
[ 12.150124] nouveau 0000:01:00.0: DRM: VRAM: 31 MiB
[ 12.150133] nouveau 0000:01:00.0: DRM: GART: 128 MiB
[ 12.150143] nouveau 0000:01:00.0: DRM: BMP version 5.6
[ 12.150151] nouveau 0000:01:00.0: DRM: No DCB data found in VBIOS
[ 12.151362] ttm_tt_init
[ 12.151370] ttm_tt_init_fields
[ 12.151374] ttm_tt_alloc_page_directory
[ 12.151615] BUG: kernel NULL pointer dereference, address: 00000000
Please add dump_stack(); to ttm_tt_init() and report back with the
backtrace.
I can't see how this is called from the nouveau code, only possibility I
see is that it is maybe called through the AGP code somehow.
Christian.
