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:
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.
Small, 8GB and empty.
Created attachment 938244 [details] coredump.tar.bz2
Created attachment 938245 [details] gdb backtrace on coredump gdb --core=coredump <gdb> backtrace
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
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