Thread (7 messages) 7 messages, 2 authors, 2016-09-06

Re: [bcachefs] BUG: soft lockup - CPU#0 stuck for 22s! [bch_copygc_read:5328]

From: Kent Overstreet <hidden>
Date: 2016-09-06 02:24:11

On Sun, Sep 04, 2016 at 08:21:17PM +0200, Marcin wrote:
W dniu 2016-09-04 02:17, Kent Overstreet napisał(a):

Hi!
quoted
On Sat, Sep 03, 2016 at 11:29:49PM +0200, Marcin wrote:
quoted
Hi!
Kernel at commit c820493652e830dc050e1418301e1bdec5691a1e

I createt to devices, fast has size
# blockdev --getsz /dev/sde1
20971520
and slower device:
# blockdev --getsz /dev/sdd1
2930209551

I was copying files from one disk to bcache, after some time I got:
 BUG: soft lockup - CPU#0 stuck for 22s! [bch_copygc_read:5328]
Thanks for the report - can you run addr2line with your vmlinux file,
and the
RIP?

addr2line -i -e vmlinux ffffffffc028795b
It returned:
??:0

Probably due to I'm using bcache as module.
<long story>
As I mentioned before I wasn't sure which branch I used to test.
In case I didn't mention before - bcache-dev. This bug in the bcache-encryption
branch is a bit disconcerting though since my tests never hit it, but don't
worry about it - I'll chase it down.
Please look at line with "bucket size":
bucket_size:            768
If bucket size is higher than (probably) 512 then I can't mount simple
(without tiering) bcachefs filesystem. If I use such big device in tiered
bcachefs I'm expieriencing random problems with stability of box.
I think that bug in mail's subject is only random symptom of problem when
device is formated with bucket size >512.
What is going inside kernel in this case, is overwittem memory of other
processes?
Whoops - that one is a bug in bcache-tools, non power of two bucket sizes aren't
supported (might be someday, but aren't currently). I just pushed a fix for that
to bcache-tools.
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