segfault when creating pool

[jefferai]

Hello,

I'm on Ubuntu 12.04 LTS using the current zfs/spl packages from the official PPA (version 0.6.0.86-0ubuntu1~precise1).

I get a repeated segmentation fault when I try to create the pool:

root@wiki:~# zpool create -o ashift=12,listsnaps=on -O atime=off,compression=lzjb,normalization=formD,utf8only=on -m /storage storage vdb
Segmentation fault

dmesg shows:

[ 2768.876276] zpool[2272]: segfault at 43c ip 00007f8f704f7d4f sp 00007fffc59f2110 error 6 in libc-2.15.so[7f8f703ef000+1b5000]

Please let me know how I can help debug this.

Thanks!

[jefferai]

I don't get this segfault when I take out the "listsnaps=on" from the -o property.

[jefferai]

Okay, I now realize that I had totally wrong syntax for the comment. I'd argue that it still shouldn't segfault, though.

[lundman]

Yeah it does seem to be the wrong syntax, basically it is crashing here:

#1  0x00007ffff747bf34 in vsnprintf (__ap=0x7fffffff8108, 
    __fmt=<optimized out>, __n=1024, __s=0x43c <Address 0x43c out of bounds>)
    at /usr/include/x86_64-linux-gnu/bits/stdio2.h:78
#2  zfs_error_aux (hdl=hdl@entry=0x0, fmt=<optimized out>)
    at ../../lib/libzfs/libzfs_util.c:244
#3  0x00007ffff747bfcc in str2shift (hdl=hdl@entry=0x0, 
    buf=0x61cf6a ",listsnaps=on") at ../../lib/libzfs/libzfs_util.c:1300
#4  0x00007ffff747e055 in zfs_nicestrtonum (hdl=hdl@entry=0x0, 
    value=0x61cf68 "12,listsnaps=on", num=num@entry=0x7fffffff8260)
    at ../../lib/libzfs/libzfs_util.c:1378

Which is pretty much the line trying to tell you about the syntax problem:

            zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                                        "invalid numeric suffix '%s'"), buf);

It is easily patched with something like https://github.com/lundman/zfs-master/commit/b80557183fcbb05f4ebc0472723ae80a76403ec3

 # zpool create -f -o ashift=12,listsnaps=on -O atime=off,compression=lzjb,normalization=formD,utf8only=on -m /storage storage ~/src/pool-image.bin
 cannot create 'storage': invalid numeric suffix ',listsnaps=on'
 # zpool create -f -o ashift=12 -o listsnaps=on -O atime=off,compression=lzjb,normalization=formD,utf8only=on -m /storage storage ~/src/pool-image.bin
 cannot create 'storage': 'atime' must be one of 'on | off'
 # zpool create -f -o ashift=12 -o listsnaps=on -O atime=off -O compression=lzjb -O normalization=formD -O utf8only=on -m /storage storage ~/src/pool-image.bin 
 #
Success!

[behlendorf]

@jefferai It absolutely shouldn't segfault regardless of your syntax.

@lundman I was going to say we should make the hdl == NULL test further up the stack, but then I looked at the code and see they're already doing this in zfs_nicestrtonum(). So in the interests of being consistent I'm OK with your patch as is, I'll get it merged. Thanks for running this down.