Re: [ANNOUNCE] Linux-2.4.32-hf32.5

From: Willy Tarreau
Date: Fri May 26 2006 - 10:16:20 EST


[ I removed Jari who told me yesterday he did not need to be Cc'd ]

On Fri, May 26, 2006 at 11:28:51PM +1000, Grant Coady wrote:
> On Fri, 26 May 2006 14:16:23 +0200, Willy Tarreau <willy@xxxxxxxxx> wrote:
>
> >Could you please pass it through ksymoops so that we get an idea about the
> >function causing this ? What was the last version not causing it ? hf32.4 ?
>
> Yes, hf32.4 okay, see: <http://bugsplatter.mine.nu/test/linux-2.4/>
>
> >This looks like a structure member gets accessed while a pointer is NULL,
> >if you always get 0x88... I would be it could come from
> >2.4.32-ext3-link-unlink-race-1, but that would be strange.
>
> Good guess! The previous version comment stripped .configs are
> linked by machine name from the summary page above.

Hmmm that's bad, this one has been merged into mainline.
It would look like dentry->d_inode is NULL here :

double_down(&dir->i_zombie, &dentry->d_inode->i_zombie);

I don't know how this can be fixed, though ! My first guess would be to
quickly revert the patch.

Marcelo, do you have Vadim Egorov's address ? I think he can help us on this,
after all it is his patch and he found explained the bug !

Right now I will release -hf32.6 quickly.

> Localtime 23:28 so it will be overnight delay before I reply to
> queries for further info ;)
>
> grant@sempro:~$ ksymoops -v ~/linux/linux-2.4.32-hf32.5/vmlinux -m /boot/System.map-2.4.32-hf32.5 oops
> ksymoops 2.4.11 on i686 2.6.16.17a. Options used
> -v /home/grant/linux/linux-2.4.32-hf32.5/vmlinux (specified)
> -k /proc/ksyms (default)
> -l /proc/modules (default)
> -o /lib/modules/2.6.16.17a/ (default)
> -m /boot/System.map-2.4.32-hf32.5 (specified)
>
> Error (regular_file): read_ksyms stat /proc/ksyms failed
> ksymoops: No such file or directory
> No modules in ksyms, skipping objects
> No ksyms, skipping lsmod
> Unable to handle kernel NULL pointer dereference at virtual address 00000088 printing eip:
> c013ee43
> *pde = 00000000
> Oops: 0002
> CPU: 0
> EIP: 0010:[<c013ee43>] Not tainted
> Using defaults from ksymoops -t elf32-i386 -a i386
> EFLAGS: 00010246
> eax: 00000088 ebx: c19bb5c0 ecx: 00000088 edx: f7bf0005
> esi: f7e3c508 edi: c19bb5c0 ebp: f7e3c480 esp: f7e6bf18
> ds: 0018 es: 0018 ss: 0018
> Process swapper (pid: 1, stackpage=f7e6b000)
> Stack: c19bb5c0 00000000 c19bb5c0 f7bf0000 f7e6bf3c c19bb5c0 c013f056 f7e3c480
> c19bb5c0 c19bb440 c19ac140 f7bf0005 00000004 01c0d8cc 00000010 00000000
> c013e727 00000803 c02a18f6 c0105000 0008e000 c0302bfb c02a18f6 f7bf0000
> Call Trace: [<c013f056>] [<c013e727>] [<c0105000>] [<c013e890>] [<c01051f3>]
> [<c0105085>] [<c010568b>] [<c0105070>]
> Code: ff 08 0f 88 8f 16 00 00 8b 5f 08 85 db 74 0c 8b 47 0c 39 68
>
>
> >>EIP; c013ee43 <vfs_unlink+33/190> <=====
>
> Trace; c013f056 <sys_unlink+b6/120>
> Trace; c013e727 <vfs_mknod+c7/120>
> Trace; c0105000 <_stext+0/0>
> Trace; c013e890 <sys_mknod+110/180>
> Trace; c01051f3 <prepare_namespace+73/140>
> Trace; c0105085 <init+15/110>
> Trace; c010568b <arch_kernel_thread+2b/40>
> Trace; c0105070 <init+0/110>
>
> Code; c013ee43 <vfs_unlink+33/190>
> 00000000 <_EIP>:
> Code; c013ee43 <vfs_unlink+33/190> <=====
> 0: ff 08 decl (%eax) <=====
> Code; c013ee45 <vfs_unlink+35/190>
> 2: 0f 88 8f 16 00 00 js 1697 <_EIP+0x1697>
> Code; c013ee4b <vfs_unlink+3b/190>
> 8: 8b 5f 08 mov 0x8(%edi),%ebx
> Code; c013ee4e <vfs_unlink+3e/190>
> b: 85 db test %ebx,%ebx
> Code; c013ee50 <vfs_unlink+40/190>
> d: 74 0c je 1b <_EIP+0x1b>
> Code; c013ee52 <vfs_unlink+42/190>
> f: 8b 47 0c mov 0xc(%edi),%eax
> Code; c013ee55 <vfs_unlink+45/190>
> 12: 39 68 00 cmp %ebp,0x0(%eax)
>
> <0>Kernel panic: Attempted to kill init!
>
> 1 error issued. Results may not be reliable.
>
> Thanks,
> Grant.

Thank you very much Grant,
Willy

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