Re: btrfs restore memory corruption (bug: 82701)

Am Freitag 22 August 2014, 10:42:18 schrieb Marc Dietrich:

Am Freitag, 22. August 2014, 14:43:45 schrieb Gui Hecheng:

quoted

On Thu, 2014-08-21 at 16:19 +0200, Marc Dietrich wrote:

quoted

Am Donnerstag, 21. August 2014, 17:52:16 schrieb Gui Hecheng:

quoted

On Mon, 2014-08-18 at 11:25 +0200, Marc Dietrich wrote:

quoted

Hi,

I did a checkout of the latest btrfs progs to repair my damaged
filesystem.
Running btrfs restore gives me several failed to inflate: -6 and
crashes
with some memory corruption. I ran it again with valgrind and got:

valgrind --log-file=x2 -v --leak-check=yes btrfs restore /dev/sda9
/mnt/backup

==8528== Memcheck, a memory error detector
==8528== Copyright (C) 2002-2012, and GNU GPL'd, by Julian Seward et
al.
==8528== Using Valgrind-3.8.1 and LibVEX; rerun with -h for
copyright
info
==8528== Command: btrfs restore /dev/sda9 /mnt/backup
==8528== Parent PID: 8453
==8528==
==8528== Syscall param pwrite64(buf) points to uninitialised byte(s)
==8528==    at 0x59BE3C3: __pwrite_nocancel (in
/lib64/libpthread-2.18.so)
==8528==    by 0x41F22F: search_dir (cmds-restore.c:392)
==8528==    by 0x41F8D0: search_dir (cmds-restore.c:895)
==8528==    by 0x41F8D0: search_dir (cmds-restore.c:895)
==8528==    by 0x41F8D0: search_dir (cmds-restore.c:895)
==8528==    by 0x41F8D0: search_dir (cmds-restore.c:895)
==8528==    by 0x41F8D0: search_dir (cmds-restore.c:895)
==8528==    by 0x4204B8: cmd_restore (cmds-restore.c:1284)
==8528==    by 0x4043FE: main (btrfs.c:286)
==8528==  Address 0x66956a0 is 7,056 bytes inside a block of size
8,192
alloc'd
==8528==    at 0x4C277AB: malloc (in
/usr/lib64/valgrind/vgpreload_memcheck- amd64-linux.so)
==8528==    by 0x41EEAD: search_dir (cmds-restore.c:316)
==8528==    by 0x41F8D0: search_dir (cmds-restore.c:895)
==8528==    by 0x41F8D0: search_dir (cmds-restore.c:895)
==8528==    by 0x41F8D0: search_dir (cmds-restore.c:895)
==8528==    by 0x41F8D0: search_dir (cmds-restore.c:895)
==8528==    by 0x41F8D0: search_dir (cmds-restore.c:895)
==8528==    by 0x4204B8: cmd_restore (cmds-restore.c:1284)
==8528==    by 0x4043FE: main (btrfs.c:286)

-------------------[snip]---------------------------------
.... leaks ...
----------------------------------------------------------

For the leak below...
I've no idea why the @decompress_lzo() is not statisfied with @inbuf
with the exact size of the disk bytes.
Or maybe the compressed data had just sufferred damages...

BTW, when you wrote your data, did that kernel has the following commit
for btrfs?

	commit: 59516f6017c589e7316418fda6128ba8f829a77f

mmh, I used the master branch which is still on 3.14.2 (from k.org).

Ah, there is a development branch on another repo (repo.or.cz). Why oh why?

Guy, 

sorry to quote an earlier mail, I forgot to add you as CC on you latest post 
and I'm not subscribed to the list.

There is a development branch for btrfs-progs from david:
http://github.com/kdave/btrfs-progs.git if you would like to try.

ok, thanks will try.

But here, what I mean is your *kernel* version when you wrote your data.

I'm using btrfs since 3.14 or so (and maybe also some random distro kernel 
based on 3.11). The partition contained a lot of larger git trees and virtual 
machines - yes, not ideal for btrfs but a nice testcase ...

There is a change for btrfs-restore which depends on a kernel commit.
If you wrote your data with a older kernel and apply the 3.14.2
btrfs-progs to restore, then there may be wandering stuffs.

wow. That should never happend I think. Userspace should always be able to fix 
corruptions made by earlier kernels (except disk layout changes maybe).

Now, I am just suspecting such a scenario.

Possbile. So how to proceed? If I checkout the latest brtfs from the repo 
above and restore again, are you still interested in the results?

It seems there are lots of people reporting corruptions on the list and also 
lots of fixes posted. Maybe it's better to restart from new (format a the 
partiton) and report problems happen after that. What do you think?

Marc