On (06/16/16 15:47), Minchan Kim wrote:

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[..]

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this is what I'm getting with the [zsmalloc: keep first object offset in struct page]
applied:  "count:0 mapcount:-127". which may be not related to zsmalloc at this point.

kernel: BUG: Bad page state in process khugepaged  pfn:101db8
kernel: page:ffffea0004076e00 count:0 mapcount:-127 mapping:          (null) index:0x1

Hm, it seems double free.

It doen't happen if you disable zram? IOW, it seems to be related
zsmalloc migration?

need to test more, can't confidently answer now.

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How easy can you reprodcue it? Could you bisect it?

it takes some (um.. random) time to trigger the bug.
I'll try to come up with more details.

Could you revert [1] and retest?

[1] mm/compaction: split freepages without holding the zone lock

ok, so this is not related to zsmalloc. finally manged to reproduce
it. will fork a separate thread.

	-ss

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