Re: bio linked list corruption.

[Linus Torvalds]

On Mon, Oct 31, 2016 at 11:55 AM, Dave Jones <davej@xxxxxxxxxxxxxxxxx> wrote:
>
> BUG: Bad page state in process kworker/u8:12  pfn:4e0e39
> page:ffffea0013838e40 count:0 mapcount:0 mapping:ffff8804a20310e0 index:0x100c
> flags: 0x400000000000000c(referenced|uptodate)
> page dumped because: non-NULL mapping

Hmm. So this seems to be btrfs-specific, right?

I searched for all your "non-NULL mapping" cases, and they all seem to
have basically the same call trace, with some work thread doing
writeback and going through btrfs_writepages().

Sounds like it's a race with either fallocate hole-punching or
truncate. I'm not seeing it, but I suspect it's btrfs, since DaveJ
clearly ran other filesystems too but I am not seeing this backtrace
for anything else.

 Linus