Re: 2.6.18-rt1

From: john stultz
Date: Wed Sep 27 2006 - 20:42:28 EST

On Fri, 2006-09-22 at 13:58 +0200, Ingo Molnar wrote:
> * john stultz <johnstul@xxxxxxxxxx> wrote:
> > I'm seeing a similar issue. Although the log is a bit futzed. Maybe
> > its the sd_mod?
> >
> > at virtual address 75010000le kernel paging requestproc filesystem
> would be nice to figure out why it crashes - unfortunately i cannot
> trigger it. Could it be some build tool incompatibility perhaps? Some
> sizing issue (some module struct gets too large)?

Been looking a bit deeper into this again:

BUG: unable to handle kernel paging request at virtual address 75010000
printing eip:
*pde = cccccccc
stopped custom tracer.
Oops: 0000 [#1]
Modules linked in:
CPU: 1
EIP: 0060:[<c01354ea>] Not tainted VLI
EFLAGS: 00010282 (2.6.18-rtjohn #9)
EIP is at lookup_symbol+0x37/0x5b
eax: 00000018 ebx: c0387a10 ecx: f7df7e58 edx: c0349c7e
esi: 75010000 edi: f881a229 ebp: c038a524 esp: f7df7e5c
ds: 007b es: 007b ss: 0068 preempt: 00000000
Process insmod (pid: 453, ti=f7df6000 task=c2b54030 task.ti=f7df6000)
Stack: f881f940 f8820c80 f881a229 f7df7ea4 c013555c f881a229 c03855a0
f881f940 f8820c80 f881a229 00000000 c01362dd f881a229 f7df7ea0
00000001 00000000 f881a229 f881f940 000004f0 0000003c c0136855
Call Trace:
[<c013555c>] __find_symbol+0x26/0x2e0
[<c01362dd>] resolve_symbol+0x23/0x5f
[<c0136855>] simplify_symbols+0x7e/0xf0
[<c01375b0>] load_module+0x7c4/0xc14
[<c0137a60>] sys_init_module+0x3d/0x171
[<c0102855>] sysenter_past_esp+0x56/0x79
Code: 55 53 ff 74 24 1c 68 5f 9c 34 c0 e8 df 80 fe ff 83 c4 10 39 eb 73
31 53 68 7e 9c 34 c0 e8 cd 80 fe ff 5e 5f 8b 73 04 8b 7c 24 14 <ac> ae
75 08 84 c0 75 f8 31 c0 eb 04 19 c0 0c 01 85 c0 75 04 89
EIP: [<c01354ea>] lookup_symbol+0x37/0x5b SS:ESP 0068:f7df7e5c

Put some debugging into __find_symbol() and came up w/ this:

lookup_symbol: scsi_print_sense_hdr 0xc0385590 0xc038a514

Where it goes through that range in kernel_symbol increments.

The last one it checks before crashing is: 0xc0387a10

c0385590 R __start___ksymtab
c038a514 R __stop___ksymtab

That looks right. Now looking up 0xc0387a10, there's no symbol there.

c03879e8 r __ksymtab_find_next_bit
c03879f0 r __ksymtab_find_next_zero_bit
c03879f8 R __write_lock_failed
c0387a18 R __read_lock_failed
c0387a2c r __ksymtab___delay
c0387a34 r __ksymtab___const_udelay
c0387a3c r __ksymtab___udelay
c0387a44 r __ksymtab___ndelay

That __read/__write_lock_failed bit looks wrong.

That's as far as I've gotten so far, but will email with more as I find


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