[Unionfs] Panic in unionfs 2.2.4

[Erez Zadok]

In message <2c03f9590803252326p22594f82h99c0a7583681b546 at mail.gmail.com>, "Lucas C. Villa Real" writes:
> On Tue, Mar 25, 2008 at 1:42 PM, Erez Zadok <ezk at cs.sunysb.edu> wrote:
> > In message <21590311.638981205283907228.JavaMail.root at tahiti.vyatta.com>, Bob Gilligan writes:
> >  > Hi Folks -- We're seeing a consistent panic in unionfs 2.2.4 running on
> >  > Linux 2.6.23.16.  The panic is due to an assertion failure in dget() in
> >  > dcache.h.
> >  [...]
> >
> >  Bob, can you please try unionfs-2.3 (just released) and let me know if you
> >  can still tickle this bug?  If so, please open an official Bugzilla report
> >  so we can more easily track the bug (the test script you provided would be
> >  very helpful).
> 
> For the record, I'm facing exactly the same problem here. I've just
> tested with 2.6.24.4 and unionfs 2.3.1. The bug is always
> reproducible:
> 
> kernel BUG at include/linux/dcache.h:323!
> invalid opcode: 0000 [#1] PREEMPT SMP
> Modules linked in: ndiswrapper i915 drm ipv6 snd_pcm_oss snd_mixer_oss
> hfsplus joydev appletouch sky2 video i2c_i801 battery output thermal
> snd_hda_intel button rtc_cmos rtc_core rtc_lib shpchp ac processor
> ohci1394 i2c_core intel_agp iTCO_wdt pci_hotplug snd_pcm snd_timer snd
> snd_page_alloc
> 
> Pid: 10131, comm: cp Tainted: P        (2.6.24.4-Gobo #1)
> EIP: 0060:[<c10a4d62>] EFLAGS: 00010246 CPU: 1
> EIP is at d_alloc+0x172/0x190
> EAX: ef583f24 EBX: ef583ee0 ECX: 00000000 EDX: ef583f44
> ESI: ef8bb033 EDI: ef583f4e EBP: ef5f1550 ESP: ef80bdd4
>  DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
> Process cp (pid: 10131, ti=ef80a000 task=ef8fb170 task.ti=ef80a000)
> Stack: ef80be38 ef583ee0 ef5f1550 00000000 ef80bf04 ef80be38 c1099f21 ef80be44
>        f75cd280 ef5de068 ef5de0e0 ef80be38 ef8bb033 ef5de068 ef8bb029 c109bf02
>        ef80bf04 ef8bb029 00000000 00000000 ef192078 c10ea4b4 ef80be80 00000000
> Call Trace:
>  [<c1099f21>] do_lookup+0x131/0x190
>  [<c109bf02>] __link_path_walk+0x7e2/0xdb0
>  [<c10ea4b4>] reiserfs_readdir+0x3c4/0x4c0
>  [<c109c515>] link_path_walk+0x45/0xc0
>  [<c109c778>] do_path_lookup+0x78/0x220
>  [<c109b53a>] getname+0x9a/0xf0
>  [<c109d1cb>] __user_walk_fd+0x3b/0x60
>  [<c1095def>] vfs_lstat_fd+0x1f/0x50
>  [<c1095e9f>] sys_lstat64+0xf/0x30
>  [<c1093612>] __fput+0x112/0x170
> 
> This have been tested with both reiserfs and ext3 underneath. Do you
> have any ideas?
> 
> Thanks,
> 
> -- 
> Lucas
> powered by /dev/dsp

Lucas, I don't see unionfs directly involved in the stack trace above.  Do
you have more information?  Can I get a livecd to boot myself, and
instructions how to tickle this bug?

Thanks,
Erez.