Re: [REGRESSION] BUG: KFENCE: memory corruption in drm_gem_put_pages+0x186/0x250

[Thomas Zimmermann <tzimmermann@suse.de>]

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Hi

Am 02.10.23 um 17:38 schrieb Oleksandr Natalenko:
> On pondělí 2. října 2023 16:32:45 CEST Matthew Wilcox wrote:
>> On Mon, Oct 02, 2023 at 01:02:52PM +0200, Oleksandr Natalenko wrote:
>>>>>>> BUG: KFENCE: memory corruption in drm_gem_put_pages+0x186/0x250
>>>>>>>
>>>>>>> Corrupted memory at 0x00000000e173a294 [ ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ] (in kfence-#108):
>>>>>>>   drm_gem_put_pages+0x186/0x250
>>>>>>>   drm_gem_shmem_put_pages_locked+0x43/0xc0
>>>>>>>   drm_gem_shmem_object_vunmap+0x83/0xe0
>>>>>>>   drm_gem_vunmap_unlocked+0x46/0xb0
>>>>>>>   drm_fbdev_generic_helper_fb_dirty+0x1dc/0x310
>>>>>>>   drm_fb_helper_damage_work+0x96/0x170
>>>
>>> Matthew, before I start dancing around, do you think ^^ could have the same cause as 0b62af28f249b9c4036a05acfb053058dc02e2e2 which got fixed by 863a8eb3f27098b42772f668e3977ff4cae10b04?
>>
>> Yes, entirely plausible.  I think you have two useful points to look at
>> before delving into a full bisect -- 863a8e and the parent of 0b62af.
>> If either of them work, I think you have no more work to do.
> 
> OK, I've did this against v6.5.5:
> 
> ```
> git log --oneline HEAD~3..
> 7c1e7695ca9b8 (HEAD -> test) Revert "mm: remove struct pagevec"
> 8f2ad53b6eac6 Revert "mm: remove check_move_unevictable_pages()"
> fa1e3c0b5453c Revert "drm: convert drm_gem_put_pages() to use a folio_batch"
> ```
> 
> then rebooted the host multiple times, and the issue is not seen any more.
> 
> So I guess 3291e09a463870610b8227f32b16b19a587edf33 is the culprit.

Ignore my other email. It's apparently been fixed already. Thanks!

Best regards
Thomas

> 
> Thanks.
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)

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