Hello,
On Thu, Feb 25, 2010 at 04:36:23PM +0530, Chatterjee, Amit wrote:
Migrated to 2.6.33-rc8-rt2 but still am facing the same issue.
Regards,
Amit
-Original Message-
From: linux-rt-users-ow...@vger.kernel.org
[mailto:linux-rt-users-ow...@vger.kernel.org] On Behalf Of Chatterjee, Amit
Sent: Wednesday, February 24, 2010 5:50 PM
To: LKML; rt-users
Subject: 2.6.33-rc8-rt1 on Beagle
Hi,
I am facing NULL pointer deference error with beagle board. The
bootargs used are -
setenv bootargs 'console=ttyS2,115200n8 root=/dev/mmcblk0p2 rootwait
rootfstype=ext3 omapfb.mode=dvi:800x600mr...@60 omapdss.def_disp=dvi
omapfb.vram=0:8M,1:2M,2:4M mem=216M'
setenv bootcmd 'mmc init;fatload mmc 0 0x8020 uImage;bootm 0x8020'
The crash log is as follows -
Waiting for root device /dev/mmcblk0p2...
Unable to handle kernel NULL pointer dereference at virtual address
pgd = c0004000
[] *pgd=
Internal error: Oops: 805 [#1] PREEMPT
last sysfs file:
Modules linked in:
CPU: 0Not tainted (2.6.33-rc8-rt1 #3)
PC is at rt_spin_lock_slowlock+0x64/0x220
This corresponds to:
BUG_ON(rt_mutex_owner(lock) == current);
in rt_spin_lock_slowlock. If you had CONFIG_BUG_VERBOSE this would have
been more obvious.
LR is at rt_spin_lock_slowlock+0x24/0x220
pc : [c029f85c]lr : [c029f81c]psr: 6093
sp : cd1a1ed8 ip : cd1a1f08 fp : 0053
r10: cd3bc664 r9 : c039c8c4 r8 : cd3bc400
r7 : cd1a r6 : cd3bc664 r5 : 6013 r4 : cd3bc664
r3 : r2 : cd3fb480 r1 : r0 : cd1a1ed8
Flags: nZCv IRQs off FIQs on Mode SVC_32 ISA ARM Segment kernel
Control: 10c5387d Table: 80004019 DAC: 0017
Process irq/83-mmc0 (pid: 355, stack limit = 0xcd1a02e8)
Stack: (0xcd1a1ed8 to 0xcd1a2000)
1ec0: 0001 0006
1ee0: cd070040 c0397f48 0001 cd3fb480 0002 cd3bc664 6013
1f00: cd1a c029f9f0 cd3bc600 cd0c3ef4 cd3bc664
1f20: cd3bc400 cd3bc664 c0213850 cd0c2000 cd0c201c cd3fb480 0017
1f40: cd3bc600 00018000 0001 cd3bc664 c020bb94
1f60: cd0c3f24 c02145fc c039c880 cd3d07c0 cd1a cd3d07e4 0800 c039c8c4
1f80: c039c8dc c00768e8 cd3d07c0 0032 cd1a1f88 cd021e58 cd1a1fbc c0076828
1fa0: cd3d07c0 c0060ae8
1fc0: cd1a1fc0 cd1a1fc0 cd1a1fc8 cd1a1fc8 cd1a1fd8 cd1a1fd8
1fe0: c0028ec4 107fcd00 0a33ef94
[c029f85c] (rt_spin_lock_slowlock+0x64/0x220) from [c0213850]
(omap_hsmmc_request+0x44/0x400)
[c0213850] (omap_hsmmc_request+0x44/0x400) from [c020bb94]
(mmc_request_done+0x64/0x90)
[c020bb94] (mmc_request_done+0x64/0x90) from [c02145fc]
(omap_hsmmc_irq+0x364/0x46c)
[c02145fc] (omap_hsmmc_irq+0x364/0x46c) from [c00768e8]
(irq_thread+0xc0/0x208)
[c00768e8] (irq_thread+0xc0/0x208) from [c0060ae8] (kthread+0x78/0x80)
[c0060ae8] (kthread+0x78/0x80) from [c0028ec4]
(kernel_thread_exit+0x0/0x8)
Code: e597300c e1520003 1a02 e3a03000 (e5833000)
I assume the problem is that the function omap_hsmmc_request tries to be
clever in a non-rt compatible way:
/*
* Prevent races with the interrupt handler because of unexpected
* interrupts, but not if we are already in interrupt context i.e.
* retries.
*/
if (!in_interrupt()) {
spin_lock_irqsave(host-irq_lock, host-flags);
But looking at the backtrace in this context in_interrupt() would be
true in !PREEMPT_RT.
You might want to report that to the author(s) of
drivers/mmc/host/omap_hsmmc.c.
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König|
Industrial Linux Solutions | http://www.pengutronix.de/ |
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