Bug 1142486

Summary: Error 'corrupted double-linked list' when using rescue super-recover on corrupt superblock
Product: [Fedora] Fedora Reporter: Chris Murphy <bugzilla>
Component: btrfs-progsAssignee: Josef Bacik <josef>
Status: CLOSED EOL QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: 21CC: esandeen, josef, mmahut
Target Milestone: ---   
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2015-12-02 03:51:20 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Attachments:
Description Flags
coredump.tar.bz2
none
gdb backtrace on coredump none

Description Chris Murphy 2014-09-16 21:14:37 UTC
Description of problem: After zeroing superblock 0 csum, running btrfs rescue super-recover crashes.


Version-Release number of selected component (if applicable):
kernel-3.16.1-301.fc21.x86_64
btrfs-progs-3.16-1.fc21.x86_64

How reproducible:
Always


Steps to Reproduce:
1. # dd if=/dev/zero of=/dev/sdb bs=4 seek=16384 count=1
2. # btrfs rescue super-recover /dev/sdb -v
3. "Make sure this is a btrfs disk otherwise the tool will destroy other fs, Are you sure? [y/N]: y"


Actual results:

Reports "Recovered bad superblocks successful" then traceback.

*** Error in `btrfs': corrupted double-linked list: 0x0000000000b23e40 ***
======= Backtrace: =========
/lib64/libc.so.6(+0x7a77e)[0x7f05d52e277e]
/lib64/libc.so.6(+0x80b03)[0x7f05d52e8b03]
/lib64/libc.so.6(+0x81c88)[0x7f05d52e9c88]
/lib64/libc.so.6(cfree+0x4c)[0x7f05d52ee6ec]
btrfs[0x425ec6]
btrfs[0x406902]
/lib64/libc.so.6(__libc_start_main+0xf0)[0x7f05d52880e0]
btrfs[0x406a04]
======= Memory map: ========
00400000-0046b000 r-xp 00000000 08:03 136399110                          /usr/sbin/btrfs
0066a000-0066d000 r--p 0006a000 08:03 136399110                          /usr/sbin/btrfs
0066d000-0066e000 rw-p 0006d000 08:03 136399110                          /usr/sbin/btrfs
0066e000-00671000 rw-p 00000000 00:00 0 
00b23000-00b45000 rw-p 00000000 00:00 0                                  [heap]
7f05d5051000-7f05d5067000 r-xp 00000000 08:03 270295759                  /usr/lib64/libgcc_s-4.9.1-20140813.so.1
7f05d5067000-7f05d5266000 ---p 00016000 08:03 270295759                  /usr/lib64/libgcc_s-4.9.1-20140813.so.1
7f05d5266000-7f05d5267000 r--p 00015000 08:03 270295759                  /usr/lib64/libgcc_s-4.9.1-20140813.so.1
7f05d5267000-7f05d5268000 rw-p 00016000 08:03 270295759                  /usr/lib64/libgcc_s-4.9.1-20140813.so.1
7f05d5268000-7f05d5425000 r-xp 00000000 08:03 270069170                  /usr/lib64/libc-2.19.90.so
7f05d5425000-7f05d5625000 ---p 001bd000 08:03 270069170                  /usr/lib64/libc-2.19.90.so
7f05d5625000-7f05d5629000 r--p 001bd000 08:03 270069170                  /usr/lib64/libc-2.19.90.so
7f05d5629000-7f05d562b000 rw-p 001c1000 08:03 270069170                  /usr/lib64/libc-2.19.90.so
7f05d562b000-7f05d562f000 rw-p 00000000 00:00 0 
7f05d562f000-7f05d5647000 r-xp 00000000 08:03 271246379                  /usr/lib64/libpthread-2.19.90.so
7f05d5647000-7f05d5846000 ---p 00018000 08:03 271246379                  /usr/lib64/libpthread-2.19.90.so
7f05d5846000-7f05d5847000 r--p 00017000 08:03 271246379                  /usr/lib64/libpthread-2.19.90.so
7f05d5847000-7f05d5848000 rw-p 00018000 08:03 271246379                  /usr/lib64/libpthread-2.19.90.so
7f05d5848000-7f05d584c000 rw-p 00000000 00:00 0 
7f05d584c000-7f05d586d000 r-xp 00000000 08:03 270902273                  /usr/lib64/liblzo2.so.2.0.0
7f05d586d000-7f05d5a6c000 ---p 00021000 08:03 270902273                  /usr/lib64/liblzo2.so.2.0.0
7f05d5a6c000-7f05d5a6d000 r--p 00020000 08:03 270902273                  /usr/lib64/liblzo2.so.2.0.0
7f05d5a6d000-7f05d5a6e000 rw-p 00021000 08:03 270902273                  /usr/lib64/liblzo2.so.2.0.0
7f05d5a6e000-7f05d5a83000 r-xp 00000000 08:03 271667474                  /usr/lib64/libz.so.1.2.8
7f05d5a83000-7f05d5c82000 ---p 00015000 08:03 271667474                  /usr/lib64/libz.so.1.2.8
7f05d5c82000-7f05d5c83000 r--p 00014000 08:03 271667474                  /usr/lib64/libz.so.1.2.8
7f05d5c83000-7f05d5c84000 rw-p 00015000 08:03 271667474                  /usr/lib64/libz.so.1.2.8
7f05d5c84000-7f05d5d8b000 r-xp 00000000 08:03 270902274                  /usr/lib64/libm-2.19.90.so
7f05d5d8b000-7f05d5f8a000 ---p 00107000 08:03 270902274                  /usr/lib64/libm-2.19.90.so
7f05d5f8a000-7f05d5f8b000 r--p 00106000 08:03 270902274                  /usr/lib64/libm-2.19.90.so
7f05d5f8b000-7f05d5f8c000 rw-p 00107000 08:03 270902274                  /usr/lib64/libm-2.19.90.so
7f05d5f8c000-7f05d5fc7000 r-xp 00000000 08:03 270069155                  /usr/lib64/libblkid.so.1.1.0
7f05d5fc7000-7f05d61c7000 ---p 0003b000 08:03 270069155                  /usr/lib64/libblkid.so.1.1.0
7f05d61c7000-7f05d61ca000 r--p 0003b000 08:03 270069155                  /usr/lib64/libblkid.so.1.1.0
7f05d61ca000-7f05d61cb000 rw-p 0003e000 08:03 270069155                  /usr/lib64/libblkid.so.1.1.0
7f05d61cb000-7f05d61cc000 rw-p 00000000 00:00 0 
7f05d61cc000-7f05d61d0000 r-xp 00000000 08:03 271246592                  /usr/lib64/libuuid.so.1.3.0
7f05d61d0000-7f05d63cf000 ---p 00004000 08:03 271246592                  /usr/lib64/libuuid.so.1.3.0
7f05d63cf000-7f05d63d0000 r--p 00003000 08:03 271246592                  /usr/lib64/libuuid.so.1.3.0
7f05d63d0000-7f05d63d1000 rw-p 00004000 08:03 271246592                  /usr/lib64/libuuid.so.1.3.0
7f05d63d1000-7f05d63f5000 r-xp 00000000 08:03 269926478                  /usr/lib64/ld-2.19.90.so
7f05d65d8000-7f05d65dd000 rw-p 00000000 00:00 0 
7f05d65f0000-7f05d65f4000 rw-p 00000000 00:00 0 
7f05d65f4000-7f05d65f5000 r--p 00023000 08:03 269926478                  /usr/lib64/ld-2.19.90.so
7f05d65f5000-7f05d65f6000 rw-p 00024000 08:03 269926478                  /usr/lib64/ld-2.19.90.so
7f05d65f6000-7f05d65f7000 rw-p 00000000 00:00 0 
7fffa0176000-7fffa0197000 rw-p 00000000 00:00 0                          [stack]
7fffa01a3000-7fffa01a5000 r-xp 00000000 00:00 0                          [vdso]
7fffa01a5000-7fffa01a7000 r--p 00000000 00:00 0                          [vvar]
ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0                  [vsyscall]
Aborted (core dumped)




Expected results:

No crash.

Additional info:

Comment 1 Eric Sandeen 2014-09-16 21:24:32 UTC
Steps to Reproduce:
1. # dd if=/dev/zero of=/dev/sdb bs=4 seek=16384 count=1
2. # btrfs rescue super-recover /dev/sdb -v
3. "Make sure this is a btrfs disk otherwise the tool will destroy other fs, Are you sure? [y/N]: y"

Presumably /dev/sdb was a btrfs filesystem?  how big?

If this was using the fedora btrfs-progs rpm, attaching the core file would let us gather more info.

Comment 2 Chris Murphy 2014-09-16 21:39:19 UTC
Small, 8GB and empty.

Comment 3 Chris Murphy 2014-09-16 21:39:48 UTC
Created attachment 938244 [details]
coredump.tar.bz2

Comment 4 Chris Murphy 2014-09-16 21:45:45 UTC
Created attachment 938245 [details]
gdb backtrace on coredump

gdb --core=coredump
<gdb> backtrace

Comment 5 Eric Sandeen 2014-09-17 16:38:46 UTC
valgrind tells us what went wrong:

Make sure this is a btrfs disk otherwise the tool will destroy other fs, Are you sure? [y/N]: y
Recovered bad superblocks successful
==42039== Invalid read of size 8
==42039==    at 0x426BD9: btrfs_recover_superblocks (list.h:204)
==42039==    by 0x421C79: cmd_super_recover (cmds-rescue.c:148)
==42039==    by 0x40420A: handle_command_group (btrfs.c:145)
==42039==    by 0x421B54: cmd_rescue (cmds-rescue.c:162)
==42039==    by 0x404199: main (btrfs.c:247)
==42039==  Address 0x4c250b0 is 48 bytes inside a block of size 96 free'd
==42039==    at 0x4A063F0: free (vg_replace_malloc.c:446)
==42039==    by 0x43C77E: btrfs_close_devices (volumes.c:196)
==42039==    by 0x42F5D1: close_ctree (disk-io.c:1404)
==42039==    by 0x426A85: btrfs_recover_superblocks (super-recover.c:340)
==42039==    by 0x421C79: cmd_super_recover (cmds-rescue.c:148)
==42039==    by 0x40420A: handle_command_group (btrfs.c:145)
==42039==    by 0x421B54: cmd_rescue (cmds-rescue.c:162)
==42039==    by 0x404199: main (btrfs.c:247)
==42039== 
==42039== Invalid free() / delete / delete[] / realloc()
==42039==    at 0x4A063F0: free (vg_replace_malloc.c:446)
==42039==    by 0x426C22: btrfs_recover_superblocks (super-recover.c:101)
==42039==    by 0x421C79: cmd_super_recover (cmds-rescue.c:148)
==42039==    by 0x40420A: handle_command_group (btrfs.c:145)
==42039==    by 0x421B54: cmd_rescue (cmds-rescue.c:162)
==42039==    by 0x404199: main (btrfs.c:247)
==42039==  Address 0x4c25080 is 0 bytes inside a block of size 96 free'd
==42039==    at 0x4A063F0: free (vg_replace_malloc.c:446)
==42039==    by 0x43C77E: btrfs_close_devices (volumes.c:196)
==42039==    by 0x42F5D1: close_ctree (disk-io.c:1404)
==42039==    by 0x426A85: btrfs_recover_superblocks (super-recover.c:340)
==42039==    by 0x421C79: cmd_super_recover (cmds-rescue.c:148)
==42039==    by 0x40420A: handle_command_group (btrfs.c:145)
==42039==    by 0x421B54: cmd_rescue (cmds-rescue.c:162)
==42039==    by 0x404199: main (btrfs.c:247)
==42039== 
==42039== 
==42039== HEAP SUMMARY:
==42039==     in use at exit: 0 bytes in 0 blocks
==42039==   total heap usage: 72 allocs, 73 frees, 140,384 bytes allocated
==42039== 
==42039== All heap blocks were freed -- no leaks are possible
==42039== 
==42039== For counts of detected and suppressed errors, rerun with: -v
==42039== ERROR SUMMARY: 2 errors from 2 contexts (suppressed: 6 from 6)


it's freeing fs_devices twice:

        close_ctree(root); // <-- here
no_recover:
        recover_err_str(ret);
        free_recover_superblock(&recover); // <-- and here

Comment 6 Fedora End Of Life 2015-11-04 15:09:24 UTC
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bug reports from releases that are no longer maintained. At that time
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able to fix it before Fedora 21 is end of life. If you would still like 
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version prior this bug is closed as described in the policy above.

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Comment 7 Fedora End Of Life 2015-12-02 03:51:23 UTC
Fedora 21 changed to end-of-life (EOL) status on 2015-12-01. Fedora 21 is
no longer maintained, which means that it will not receive any further
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If you can reproduce this bug against a currently maintained version of
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