Tejun Heo wrote:
On 03/04/2010 12:44 AM, Sachin Sant wrote:
Today's next failed to boot on x86 box with following trace
Unpacking initramfs...
Freeing initrd memory: 10584k freed
BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [<c01a6b12>] pcpu_alloc+0x1cb/0x75e
*pdpt = 00000000005dd001 *pde = 0000000000000000
Oops: 0000 [#1] SMP
last sysfs file:
Modules linked in:
Pid: 1, comm: swapper Not tainted 2.6.33-autotest-next-20100303 #1
/eserver xSeries 235 -[86717AX]-
EIP: 0060:[<c01a6b12>] EFLAGS: 00010002 CPU: 1
EIP is at pcpu_alloc+0x1cb/0x75e
EAX: 00000000 EBX: c05c4100 ECX: cccccccc EDX: 00000000
ESI: 000000b0 EDI: 00000005 EBP: f5c69fa8 ESP: f5c69f2c
DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
Process swapper (pid: 1, ti=f5c68000 task=f5c66ce0 task.ti=f5c68000)
Stack:
00000000 00000005 61746164 0a383d29 5f656400 61746164 00000004 000000b0
<0> 000a3036 00000286 61637061 29656863 0a36313d c0579100 c058da30 f5c69f94
<0> c01310be c05c41cc 00000028 c058da30 f5c69fa4 c0116a73 c0492091 c0492089
Call Trace:
[<c058da30>] ? crash_save_vmcoreinfo_init+0x0/0x31a
[<c01310be>] ? log_buf_kexec_setup+0x3f/0x67
[<c058da30>] ? crash_save_vmcoreinfo_init+0x0/0x31a
[<c0116a73>] ? arch_crash_save_vmcoreinfo+0x37/0x3c
[<c058d9ff>] ? crash_notes_memory_init+0x0/0x31
[<c01a70be>] ? __alloc_percpu+0xa/0xc
[<c058da11>] ? crash_notes_memory_init+0x12/0x31
[<c0101139>] ? do_one_initcall+0x4c/0x131
[<c057b352>] ? kernel_init+0x127/0x178
[<c057b22b>] ? kernel_init+0x0/0x178
[<c0102df6>] ? kernel_thread_helper+0x6/0x10
Code: 45 a8 e9 65 ff ff ff 8b 4d 9c 8b 55 a0 8b 45 84 e8 31 fa ff ff 85
c0 89 45 a4 0f 89 fd 00 00 00 8b 45 84 8b 00 89 45 84 8b 55 84 <8b> 02
0f 18 00 90 8b 45 cc 03 05 a0 9b 57 c0 39 c2 0f 85 67 ff
EIP: [<c01a6b12>] pcpu_alloc+0x1cb/0x75e SS:ESP 0068:f5c69f2c
CR2: 0000000000000000
---[ end trace a7919e7f17c0a725 ]---
x86_64 boots fine. Have attached dmesg log.
Can you please feed the address to gdb and get the line number? Also,
is it reproducible on mainline?
I can recreate this with latest git as well (2.6.33-git9 [eaa5eec7..])
Disassembly from 2.6.33-git9 code base follows :
/usr/local/autobench/var/tmp/build/linux/mm/percpu.c:1137
if (off >= 0)
e91: 0f 89 fd 00 00 00 jns f94 <pcpu_alloc+0x2bd>
/usr/local/autobench/var/tmp/build/linux/mm/percpu.c:1116
}
restart:
/* search through normal chunks */
for (slot = pcpu_size_to_slot(size); slot < pcpu_nr_slots; slot++) {
list_for_each_entry(chunk, &pcpu_slot[slot], list) {
e97: 8b 45 84 mov -0x7c(%ebp),%eax
e9a: 8b 00 mov (%eax),%eax
e9c: 89 45 84 mov %eax,-0x7c(%ebp)
prefetch():
/usr/local/autobench/var/tmp/build/linux/arch/x86/include/asm/processor.h:886
e9f: 8b 55 84 mov -0x7c(%ebp),%edx
ea2: 8b 02 mov (%edx),%eax
^^^^^^^^^^^^^^^^^^^ EIP corresponds to this line
ea4: 8d 74 26 00 lea 0x0(%esi,%eiz,1),%esi
pcpu_alloc():
/usr/local/autobench/var/tmp/build/linux/mm/percpu.c:1116
ea8: 8b 45 cc mov -0x34(%ebp),%eax
eab: 03 05 30 00 00 00 add 0x30,%eax
eb1: 39 c2 cmp %eax,%edx
Thanks
-Sachin
--
---------------------------------
Sachin Sant
IBM Linux Technology Center
India Systems and Technology Labs
Bangalore, India
---------------------------------
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