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-owner@xxxxxxxxxxxxxxx [mailto:linux-rt-users-owner@xxxxxxxxxxxxxxx] 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-24@60 omapdss.def_disp=dvi omapfb.vram=0:8M,1:2M,2:4M mem=216M' > setenv bootcmd 'mmc init;fatload mmc 0 0x80200000 uImage;bootm 0x80200000' > > The crash log is as follows - > > Waiting for root device /dev/mmcblk0p2... > Unable to handle kernel NULL pointer dereference at virtual address 00000000 > pgd = c0004000 > [00000000] *pgd=00000000 > Internal error: Oops: 805 [#1] PREEMPT > last sysfs file: > Modules linked in: > CPU: 0 Not 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: 60000093 > sp : cd1a1ed8 ip : cd1a1f08 fp : 00000053 > r10: cd3bc664 r9 : c039c8c4 r8 : cd3bc400 > r7 : cd1a0000 r6 : cd3bc664 r5 : 60000013 r4 : cd3bc664 > r3 : 00000000 r2 : cd3fb480 r1 : 00000000 r0 : cd1a1ed8 > Flags: nZCv IRQs off FIQs on Mode SVC_32 ISA ARM Segment kernel > Control: 10c5387d Table: 80004019 DAC: 00000017 > Process irq/83-mmc0 (pid: 355, stack limit = 0xcd1a02e8) > Stack: (0xcd1a1ed8 to 0xcd1a2000) > 1ec0: 00000001 00000006 > 1ee0: cd070040 c0397f48 00000001 cd3fb480 ffffffff 00000002 cd3bc664 60000013 > 1f00: 00000000 cd1a0000 00000000 c029f9f0 00000000 cd3bc600 cd0c3ef4 cd3bc664 > 1f20: 00000000 cd3bc400 cd3bc664 c0213850 cd0c2000 cd0c201c cd3fb480 00000017 > 1f40: 00000000 cd3bc600 00000000 00018000 00000001 00000000 cd3bc664 c020bb94 > 1f60: cd0c3f24 c02145fc c039c880 cd3d07c0 cd1a0000 cd3d07e4 08000000 c039c8c4 > 1f80: c039c8dc c00768e8 cd3d07c0 00000032 cd1a1f88 cd021e58 cd1a1fbc c0076828 > 1fa0: cd3d07c0 00000000 00000000 00000000 00000000 c0060ae8 00000000 00000000 > 1fc0: cd1a1fc0 cd1a1fc0 cd1a1fc8 cd1a1fc8 00000000 00000000 cd1a1fd8 cd1a1fd8 > 1fe0: 00000000 00000000 00000000 00000000 00000000 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 1a000002 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/ | -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
