NULL ptr dereference in __remove_hrtimer()

From: Mandar Thite
Date: Sun Jan 25 2009 - 05:18:43 EST


Hello everyone,

I am trying to boot Linux kernel on OMAP5912 CPU(arch/arm/mach-omap1)
containing ARM926 core.
I have configured my Linux kernel to run in tickless mode. In the
final steps of booting, kernel is encountering " NULL pointer
dereference " in the function " rb_erase() " called from " __remove_hrtimer() ".
Following is the backtrace log emitted by the kernel.

Backtrace:
[<c012ed1c>] (rb_erase+0x0/0x358) from [<c0053f48>] (__remove_hrtimer+0x88/0x94)
r9:00000080 r8:c0285530 r7:00000000 r6:00000001 r5:c0285530
r4:c02a6298
[<c0053ec0>] (__remove_hrtimer+0x0/0x94) from [<c00548a8>]
(hrtimer_start+0x74/0x108)
r7:00000006 r6:02625a00 r5:00000000 r4:2d4cae00
[<c0054834>] (hrtimer_start+0x0/0x108) from [<c005af18>]
(tick_nohz_stop_sched_tick+0x2bc/0x3a4)
[<c005ac5c>] (tick_nohz_stop_sched_tick+0x0/0x3a4) from [<c0023318>]
(cpu_idle+0x38/0x60)
[<c00232e0>] (cpu_idle+0x0/0x60) from [<c01f7d58>] (rest_init+0x58/0x6c)
r5:c001cdc4 r4:c02bc754
[<c01f7d00>] (rest_init+0x0/0x6c) from [<c0008ad0>] (start_kernel+0x244/0x290)
[<c000888c>] (start_kernel+0x0/0x290) from [<10008034>] (0x10008034)
r6:c001cdc0 r5:c029af88 r4:00053175
Code: e3580001 01a04005 189dabf0 ea000082 (e5941008)
---[ end trace b0a66fe3e48abdda ]---
Kernel panic - not syncing: Attempted to kill the idle task!

What I understand is, address of nonexistent node is passed to rb_erase()?
Can anybody please direct me, how to investigate further into this problem?

I kindly request you to personally CC me your responses. Thanks a lot.
--Mandar
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