Re: [linus:master] [hugetlb] 7118fc2906: kernel_BUG_at_lib/list_debug.c

[Yin, Fengwei]

On 1/17/2023 3:39 PM, Vlastimil Babka wrote:
> So either the assumption of refcount being already 0 is wrong (shouldn't be,
> AFAIK?), or this atomic operation effectively prevents some very subtle race
> (although IIRC atomic_set() has no barrier semantics defined, it could still
> affect a specific CPU?
Is there difference of atomic_set() for 32bit and 64bit? This issue is only
triggered on 32bit configuration.

> 
> I guess we could
> - try to restore that set_page_count(p, 0); on current kernel to see if it
> kills the bug
I tried this. But didn't try too hard. 20 times reboot didn't trigger the issue
with this line added to commit 0af8489b02.

Without this line, hit the issue 4 times in 10 times reboot testing.


Regards
Yin, Fengwei