On Thu, Jun 16, 2016 at 05:42:11PM +0900, Sergey Senozhatsky wrote:
On (06/16/16 15:47), Minchan Kim wrote:
[..]
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.
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.
The reason I mentioned [1] is that it seems to have a bug.
isolate_freepages_block __isolate_free_page if(!zone_watermark_ok()) return 0; list_add_tail(&page->lru, freelist);
However, the page is not isolated. Joonsoo?