Re: kernel 2.6.39 (user mode linux) crashes (2.6.38 works fine)

From: Toralf Förster
Date: Fri May 20 2011 - 04:42:30 EST

richard -rw- weinberger wrote at 09:56:02
> 2011/5/20 Toralf Förster <toralf.foerster@xxxxxx>:
> > ...
> > Kernel panic - not syncing: Kernel mode fault at addr 0x0, ip 0x80a9f6b
> Looks like a NULL-pointer bug.
> What code is at address 80a9f6b?
> Use "objdump -d -S | less" to find it.
if (unlikely(ret != 0))
80a9f3a: 85 c0 test %eax,%eax
80a9f3c: 75 ca jne 80a9f08 <futex_wake+0x18>
goto out;

hb = hash_futex(&key);
80a9f3e: 8d 45 e8 lea -0x18(%ebp),%eax
80a9f41: e8 aa f6 ff ff call 80a95f0 <hash_futex>
80a9f46: 89 c2 mov %eax,%edx
head = &hb->chain;

plist_for_each_entry_safe(this, next, head, list) {
80a9f48: 8b 48 08 mov 0x8(%eax),%ecx
80a9f4b: 83 c2 08 add $0x8,%edx
80a9f4e: 8d 41 f4 lea -0xc(%ecx),%eax
80a9f51: 39 ca cmp %ecx,%edx
80a9f53: 8b 70 0c mov 0xc(%eax),%esi
80a9f56: 74 6a je 80a9fc2 <futex_wake+0xd2>
80a9f58: 89 d9 mov %ebx,%ecx
80a9f5a: 83 ee 0c sub $0xc,%esi
80a9f5d: 89 d3 mov %edx,%ebx
80a9f5f: 89 fa mov %edi,%edx
80a9f61: 89 cf mov %ecx,%edi
80a9f63: eb 12 jmp 80a9f77 <futex_wake+0x87>
80a9f65: 8d 76 00 lea 0x0(%esi),%esi
80a9f68: 8d 46 0c lea 0xc(%esi),%eax
80a9f6b: 8b 4e 0c mov 0xc(%esi),%ecx
80a9f6e: 39 c3 cmp %eax,%ebx
80a9f70: 74 4e je 80a9fc0 <futex_wake+0xd0>
80a9f72: 89 f0 mov %esi,%eax
80a9f74: 8d 71 f4 lea -0xc(%ecx),%esi
if (match_futex (&this->key, &key)) {
80a9f77: 83 f8 e4 cmp $0xffffffe4,%eax
80a9f7a: 74 ec je 80a9f68 <futex_wake+0x78>
80a9f7c: 8b 48 1c mov 0x1c(%eax),%ecx
80a9f7f: 3b 4d e8 cmp -0x18(%ebp),%ecx
80a9f82: 75 e4 jne 80a9f68 <futex_wake+0x78>
* Return 1 if two futex_keys are equal, 0 otherwise.

> Is this really 2.6.39?
No, but I didn't want to change the subject line, the bisected version is :

Toralf Förster
pgp finger print: 7B1A 07F4 EC82 0F90 D4C2 8936 872A E508 7DB6 9DA3
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