On Fri, Jan 12, 2007 at 06:46:23PM +0100, Steven Scholz wrote:
> Hi all,
>
> anyone tried 2.6.20-rc4-rt3 on an i.MX board?
Yes
>
> On my mx1ads I get
>
> RAMDISK: Compressed image found at block 0
> Unable to handle kernel NULL pointer dereference at virtual address 00000004
> pgd = c0004000
> [00000004] *pgd=00000000
> Internal error: Oops: 5 [#1]
> Modules linked in:
> CPU: 0
> PC is at get_next_event_device+0x48/0x64
> LR is at clockevents_next_event_available+0x24/0x60
> pc : [<c0058104>] lr : [<c0058144>] Not tainted
> sp : c0bb9ea0 ip : 00000000 fp : c0bb9eac
> r10: ffffffff r9 : c01d8438 r8 : c01c6bf0
> r7 : c01c4d34 r6 : c0bb8000 r5 : c01c6bf0 r4 : 20000013
> r3 : c01da08c r2 : 00000000 r1 : 00000004 r0 : 00000000
> Flags: nZCv IRQs off FIQs on Mode SVC_32 Segment kernel
> Control: C000717F
> Table: 08004000 DAC: 00000017
> Process softirq-timer/0 (pid: 4, stack limit = 0xc0bb8250)
> Stack: (0xc0bb9ea0 to 0xc0bba000)
> < - snip - >
> Backtrace:
> [<c00580bc>] (get_next_event_device+0x0/0x64) from [<c0058144>]
> (clockevents_next_event_available+0x24/0x60)
> [<c0058120>] (clockevents_next_event_available+0x0/0x60) from [<c0055704>]
> (hrtimer_run_queues+0x230/0x3c8) r5 = C01C6BF0 r4 = 00000001
> [<c00554d4>] (hrtimer_run_queues+0x0/0x3c8) from [<c0045608>]
> (run_timer_softirq+0xbc/0xe18)
> [<c004554c>] (run_timer_softirq+0x0/0xe18) from [<c0040a08>]
> (ksoftirqd+0x100/0x1b0)
> [<c0040908>] (ksoftirqd+0x0/0x1b0) from [<c0051000>] (kthread+0x110/0x13c)
> [<c0050ef0>] (kthread+0x0/0x13c) from [<c003d268>] (do_exit+0x0/0x8ac)
> r8 = 00000000 r7 = 00000000 r6 = 00000000 r5 = 00000000
> r4 = 00000000
> Code: e15c0000 cafffff8 e59f3018 e5932000 (e5921004)
> <6>note: softirq-timer/0[4] exited with preempt_count 1
> VFS: Mounted root (ext2 filesystem).
> Freeing init memory: 88K
get_next_event_device() looks like this:
static int get_next_event_device(void)
{
struct local_events *devices = &__get_cpu_var(local_eventdevices);
int i;
for (i = 0; i < devices->installed; i++) {
struct clock_event_device *evt;
evt = devices->events[i].event;
if (evt->capabilities & CLOCK_CAP_NEXTEVT)
return i;
}
if (global_eventdevice.event->capabilities & CLOCK_CAP_NEXTEVT)
return GLOBAL_CLOCK_EVENT;
return -ENODEV;
}
Loop through all available devices and search for one with CLOCK_CAP_NEXTEVT.
If none is found global_eventdevice is dereferenced, which isn't set
when you have no clock_event_device at all. Have you got the i.MX
clockevent patch applied? You can get the latest version here:
http://www.ussg.iu.edu/hypermail/linux/kernel/0701.1/0478.html
Maybe we could emit a warning message here instead of oopsing.
>
> Sascha, do you know if your clocksource/clockevent patches made it into
> mainline?
Clocksource yes, clockevent no
Sascha
--
Dipl.-Ing. Sascha Hauer | http://www.pengutronix.de
Pengutronix - Linux Solutions for Science and Industry
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