Re: NULL pointer dereference with pre 2.1.37-4

Wolfgang Wander (wwc@lars.desy.de)
Wed, 7 May 1997 16:13:51 +0200

Richard Henderson writes:
> > 1 .text.lock 00001223 c01c5a57 c01c5a57 00101000 2**0
> > CONTENTS, READONLY
>
> .text.lock is not alloc'ed. Rember to use
>
> .section .text.lock,"ax"
>

Good point. This makes the objdump look much more sane:

1 .text.lock 0000120e c01c3869 c01c3869 000c4869 2**0
CONTENTS, ALLOC, LOAD, READONLY, CODE

as compared to

1 .text.lock 0000120e c01bfac6 c01bfac6 000f8000 2**0
CONTENTS, READONLY

without the alloc and executable flags. However this is the only thing
it fixes.

Again the system hangs in the first sleep_on() with

15:57:00 Unable to handle kernel paging request at virtual address ffffff0c
15:57:00 current->tss.cr3 = 00101000, %cr3 = 00101000
15:57:00 *pde = 00000000
15:57:00 Oops: 0002
15:57:00 CPU: 0
15:57:00 EIP: 0010:[<c01c3a0c>]
15:57:00 EFLAGS: 00010247
15:57:00 eax: ffffff0c ebx: c0094000 ecx: 000007c6 edx: c02203f2
15:57:00 esi: 00000006 edi: c0095f28 ebp: c0095f14 esp: c0095ee4
15:57:01 ds: 0018 es: 0018 ss: 0018
15:57:01 Process swapper (pid: 1, process nr: 2, stackpage=c0095000)
15:57:01 Stack: c0094000 00000006 c0095f28 00000000 ffffffff 00000000 0000000
15:57:01 00000001 fffffff7 c0228008 00000000 c0095f30 c011193e c009400
15:57:01 00000000 c0094000 c01ef0a8 c0227860 c018f802 c01ef0ac 0000000
15:57:01 Call Trace:
15:57:01 Code: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
15:57:01 Started kswapd v 1.23
15:57:41 no cont in shutdown!

Wolfgang

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