reproducible panic with mount_smbfs
Yuri Pankov
yuri.pankov at gmail.com
Sun Nov 2 08:33:14 PST 2008
On Sun, Nov 02, 2008 at 05:17:18PM +0100, Attilio Rao wrote:
> 2008/11/2, Attilio Rao <attilio at freebsd.org>:
> > 2008/11/2, Yuri Pankov <yuri.pankov at gmail.com>:
> >
> > > Hi,
> > >
> > > Trying to mount nonexistent smb share with mount_smbfs leads to
> > > following panic:
> > >
> > > # mount_smbfs //yuri at lifebane/blahblah /mnt
> > >
> > > Unread portion of the kernel message buffer:
> > > smb_co_lock: recursive lock for object 1
> > > panic: Lock (lockmgr) smb_vc not locked @
> > > /usr/src/sys/modules/smbfs/../../netsmb/smb_conn.c:329.
> > > cpuid = 0
> > > KDB: stack backtrace:
> > > db_trace_self_wrapper() at db_trace_self_wrapper+0x2a
> > > panic() at panic+0x182
> > > witness_assert() at witness_assert+0x21a
> > > __lockmgr_args() at __lockmgr_args+0x17a
> > > smb_co_put() at smb_co_put+0x76
> > > smb_sm_lookup() at smb_sm_lookup+0xfe
> > > smb_usr_lookup() at smb_usr_lookup+0xcd
> > > nsmb_dev_ioctl() at nsmb_dev_ioctl+0x1f6
> > > giant_ioctl() at giant_ioctl+0x75
> > > devfs_ioctl_f() at devfs_ioctl_f+0x76
> > > kern_ioctl() at kern_ioctl+0x92
> > > ioctl() at ioctl+0xfd
> > > syscall() at syscall+0x1bf
> > > Xfast_syscall() at Xfast_syscall+0xab
> > > --- syscall (54, FreeBSD ELF64, ioctl), rip = 0x800939aec, rsp =
> > > 0x7fffffffe038, rbp = 0x7fffffffe450 ---
> > > Uptime: 6m46s
> > > Physical memory: 2032 MB
> >
> >
> > So, what is happening here is that smb_co_lock() is AFU.
> > Infact looking at the code:
> > int
> > smb_co_lock(struct smb_connobj *cp, int flags, struct thread *td)
> > {
> > ...
> > if (smb_co_lockstatus(cp, td) == LK_EXCLUSIVE &&
> > (flags & LK_CANRECURSE) == 0) {
> > SMBERROR("recursive lock for object %d\n", cp->co_level);
> > return 0;
> > }
> > ...
>
> Yuri,
> could you please test this fix:
> http://www.freebsd.org/~attilio/netsmb.diff
>
> and report if it works?
> You could get a KASSERT running but this is expected as I want to
> identify on the callers who passes a malformed request and fix it.
>
> Thanks,
> Attilio
>
>
> --
> Peace can only be achieved by understanding - A. Einstein
Thanks, Attilio.
With this patch system doesn't panic anymore with nonexistent share
names (though I had to comment out smb_co_lockstatus prototype and
function to get rid of -Werror complaints). Still getting a LOR:
netsmb_dev: loaded
lock order reversal:
1st 0xffffff0021644008 smb_vc (smb_vc) @
/usr/src/sys/modules/smbfs/../../netsmb/smb_conn.c:332
2nd 0xffffffff81037368 smbsm (smbsm) @
/usr/src/sys/modules/smbfs/../../netsmb/smb_conn.c:348
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x2a
_witness_debugger() at _witness_debugger+0x2e
witness_checkorder() at witness_checkorder+0x81e
__lockmgr_args() at __lockmgr_args+0xc2a
smb_co_lock() at smb_co_lock+0x38
smb_co_gone() at smb_co_gone+0x38
smb_sm_lookup() at smb_sm_lookup+0xfe
smb_usr_lookup() at smb_usr_lookup+0xcd
nsmb_dev_ioctl() at nsmb_dev_ioctl+0x1f6
giant_ioctl() at giant_ioctl+0x75
devfs_ioctl_f() at devfs_ioctl_f+0x76
kern_ioctl() at kern_ioctl+0x92
ioctl() at ioctl+0xfd
syscall() at syscall+0x1bf
Xfast_syscall() at Xfast_syscall+0xab
--- syscall (54, FreeBSD ELF64, ioctl), rip = 0x800939aec, rsp =
0x7fffffffe048, rbp = 0x7fffffffe460 ---
Thanks,
Yuri
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