UBIFS: Oops while rebooting 2.6.34-rc6

[Artem Bityutskiy]

Good Evening,

On Fri, 2010-05-07 at 15:16 +0200, Daniel Mack wrote:
> We've had a kernel Oops today when rebooting an ARM PXA based machine
> while file I/O via SSH was outstanding.
> 
> Daniel
> 
> # reboot
> # [  671.190085] UBIFS: un-mount UBI device 0, volume 1
> The system is going down NOW!
> Sent SIGTERM to all processes
> [  672.083833] Unable to handle kernel NULL pointer dereference at virtual address 000000ac
> [  672.094587] pgd = c0004000
> [  672.097301] [000000ac] *pgd=00000000
> [  672.100850] Internal error: Oops: 817 [#1]
> [  672.104919] last sysfs file: /sys/devices/platform/spi_gpio.0/spi0.2/value
> [  672.111741] Modules linked in: eeti_ts libertas_sdio libertas pxamci ds2760_battery w1_ds2760 wire
> [  672.120641] CPU: 0    Tainted: G        W   (2.6.34-rc6 #154)
> [  672.126376] PC is at mutex_lock+0x4/0x14
> [  672.130291] LR is at make_reservation+0x74/0x328

Hi,

is this reproducible? It looks like this came from:

journal.c:127:  mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);

May be memory corruption? Did you try to see where exectly was the oops,
on which C statement?

Do you have lockdep enabled? Can it be that lockdep somehow shutdown
first? This is unlikely, though.

May be the FS was somehow unmounted, so UBIFS freed its data structures,
and now UBIFS accesses freed memory?

Try to inject some printks to ubifs_umount() or just enable the general
UBIFS messages (enable UBIFS debugging in menuconfig first, then enable
the general messages via module parameters or sysfs, see
Documentation/filesystems/ubifs.txt).

-- 
Best Regards,
Artem Bityutskiy (Артём Битюцкий)