Re: corruption

Andrew Morton
2000-12-02T04:26:59Z

"Stephen C. Tweedie" wrote:
>
> Hi,
>
> On Fri, Dec 01, 2000 at 08:35:41AM +1100, Andrew Morton wrote:
> >
> > I bet this'll catch it:
> >
> > static __inline__ void list_del(struct list_head *entry)
> > {
> > __list_del(entry->prev, entry->next);
> > + entry->next = entry->prev = 0;
> > }
>
> No, because the buffer hash list is never referenced unless
> buffer->b_inode is non-null, so we can't ever do a double-list_del on
> the buffer.
>
> The patch below should fix it. It has been sent to Linus. The
> important part is the first hunk of the inode.c diff.

Testing test11-pre3 with your inode.c patch and the above list_del
patch. x86 dual processor, IDE. Same workload as before, except
I cut out misc001 (and the machine recovered almost immediately
when I killed everything! Need more testing to characterise this).

kernel BUG at inode.c:83! The trace is below. Now, this was
probably triggered by my list_del change. If so it means
that we're doing a list_empty() test on a list_head which
has actually been deleted from a list. So it's possibly the
actual assertion in destroy_inode() which is a little bogus.

But the wierd thing is that this BUG only hit a single time,
after three hours of intensive testing. If my theory is
right, the BUG should hit every time. Will investigate further...

ksymoops 0.7c on i686 2.4.0-test12-pre3. Options used
-V (default)
-k /proc/ksyms (default)
-l /proc/modules (default)
-o /lib/modules/2.4.0-test12-pre3/ (default)
-m /usr/src/linux/System.map (default)

Warning: You did not tell me where to find symbol information. I will
assume that the log matches the kernel and modules that are running
right now and I'll use the default options above for symbol resolution.
If the current kernel and/or modules do not match the log, you can get
more accurate output by telling me the kernel version and where to find
map, modules, ksyms etc. ksymoops -h explains the options.

Reading Oops report from the terminal
Dec 2 13:15:45 mnm kernel: invalid operand: 0000
Dec 2 13:15:45 mnm kernel: CPU: 0
Dec 2 13:15:45 mnm kernel: EIP: 0010:[<c014570e>]
Using defaults from ksymoops -t elf32-i386 -a i386
Dec 2 13:15:45 mnm kernel: EFLAGS: 00010282
Dec 2 13:15:45 mnm kernel: eax: 0000001a ebx: c78686e0 ecx: 00000000 edx: 0000002f
Dec 2 13:15:45 mnm kernel: esi: c025b800 edi: cd950960 ebp: c7869160 esp: ce611f3c
Dec 2 13:15:45 mnm kernel: ds: 0018 es: 0018 ss: 0018
Dec 2 13:15:45 mnm kernel: Process dbench (pid: 13094, stackpage=ce611000)
Dec 2 13:15:45 mnm kernel: Stack: c021b7e5 c021b8a5 00000053 c78686e0 c0146916 c78686e0 c7869160 c78686e0
Dec 2 13:15:45 mnm kernel: c0145096 c78686e0 00000000 ce610000 c013de4d c7869160 c7869160 c9b1e000
Dec 2 13:15:45 mnm kernel: ce611fa4 c7869160 cd9509d0 c013df25 cd950960 c7869160 ce610000 bffff5ca
Dec 2 13:15:45 mnm kernel: Call Trace: [<c021b7e5>] [<c021b8a5>] [<c0146916>] [<c0145096>] [<c013de4d>] [<c013df25>
Dec 2 13:15:45 mnm kernel: [<c010002b>]
Dec 2 13:15:45 mnm kernel: Code: 0f 0b 83 c4 0c 53 a1 10 d1 2a c0 50 e8 cd 3d fe ff 83 c4 08

>>EIP; c014570e <destroy_inode+1e/34> <=====
Trace; c021b7e5 <tvecs+5a3d/1a3d8>
Trace; c021b8a5 <tvecs+5afd/1a3d8>
Trace; c0146916 <iput+18e/194>
Trace; c0145096 <d_delete+66/ac>
Trace; c013de4d <vfs_unlink+18d/1c0>
Trace; c013df25 <sys_unlink+a5/118>
Trace; c010002b <startup_32+2b/cb>
Code; c014570e <destroy_inode+1e/34>
00000000 <_EIP>:
Code; c014570e <destroy_inode+1e/34> <=====
0: 0f 0b ud2a <=====
Code; c0145710 <destroy_inode+20/34>
2: 83 c4 0c add $0xc,%esp
Code; c0145713 <destroy_inode+23/34>
5: 53 push %ebx
Code; c0145714 <destroy_inode+24/34>
6: a1 10 d1 2a c0 mov 0xc02ad110,%eax
Code; c0145719 <destroy_inode+29/34>
b: 50 push %eax
Code; c014571a <destroy_inode+2a/34>
c: e8 cd 3d fe ff call fffe3dde <_EIP+0xfffe3dde> c01294ec <kmem_cache_free+0/7c>
Code; c014571f <destroy_inode+2f/34>
11: 83 c4 08 add $0x8,%esp

1 warning issued. Results may not be reliable.