Date: Sun, 2 Nov 2008 17:17:18 +0100 From: "Attilio Rao" <attilio@freebsd.org> To: "Yuri Pankov" <yuri.pankov@gmail.com> Cc: freebsd-fs@freebsd.org, freebsd-current@freebsd.org, developers@freebsd.org Subject: Re: reproducible panic with mount_smbfs Message-ID: <3bbf2fe10811020817g1409a38ep26c1ee8edf075201@mail.gmail.com> In-Reply-To: <3bbf2fe10811020737g211dfb3fs54b48e4071db2393@mail.gmail.com> References: <20081102123100.GA1434@darklight.homeunix.org> <3bbf2fe10811020737g211dfb3fs54b48e4071db2393@mail.gmail.com>
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2008/11/2, Attilio Rao <attilio@freebsd.org>:
> 2008/11/2, Yuri Pankov <yuri.pankov@gmail.com>:
>
> > Hi,
> >
> > Trying to mount nonexistent smb share with mount_smbfs leads to
> > following panic:
> >
> > # mount_smbfs //yuri@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
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