stock 2.5.36, non-preempt, non-smp. After enabling and then disabling an
ethernet sniffer, then cat'ting /proc/locks, I can reproduce this oops
easily.
<1>Unable to handle kernel NULL pointer dereference at virtual address 00000008
c01452aa
*pde = 00000000
Oops: 0000
CPU: 0
EIP: 0060:[<c01452aa>] Not tainted
Using defaults from ksymoops -t elf32-i386 -a i386
EFLAGS: 00010282
eax: 00000000 ebx: 00000000 ecx: 00000400 edx: 00000400
esi: c66c8000 edi: c8c1d894 ebp: c66c8000 esp: c7e77ea8
ds: 0068 es: 0068 ss: 0068
Stack: 00000000 00000001 00000000 c56b9344 00000004 00000400 c8c1d898 c8c1d894
c01455dc c66c8000 c8c1d894 00000001 c0267b11 00000400 00000001 c66c8000
00000000 00000400 00000400 00000400 c66c8000 c0155f0a c66c8000 c7e77f3c
Call Trace: [<c01455dc>] [<c0155f0a>] [<c0153a6d>] [<c01336c8>] [<c013ab6b>]
[<c013389a>] [<c01071cf>]
Code: 8b 58 08 8b 44 24 30 50 8b 4c 24 30 51 68 2a 7a 26 c0 56 e8
>>EIP; c01452aa <lock_get_status+1a/260> <=====
Trace; c01455dc <get_locks_status+5c/100>
Trace; c0155f0a <locks_read_proc+1a/40>
Trace; c0153a6d <proc_file_read+19d/1b0>
Trace; c01336c8 <vfs_read+98/120>
Trace; c013ab6b <sys_fstat64+2b/30>
Trace; c013389a <sys_read+2a/40>
Trace; c01071cf <syscall_call+7/b>
Code; c01452aa <lock_get_status+1a/260>
00000000 <_EIP>:
Code; c01452aa <lock_get_status+1a/260> <=====
0: 8b 58 08 mov 0x8(%eax),%ebx <=====
Code; c01452ad <lock_get_status+1d/260>
3: 8b 44 24 30 mov 0x30(%esp,1),%eax
Code; c01452b1 <lock_get_status+21/260>
7: 50 push %eax
Code; c01452b2 <lock_get_status+22/260>
8: 8b 4c 24 30 mov 0x30(%esp,1),%ecx
Code; c01452b6 <lock_get_status+26/260>
c: 51 push %ecx
Code; c01452b7 <lock_get_status+27/260>
d: 68 2a 7a 26 c0 push $0xc0267a2a
Code; c01452bc <lock_get_status+2c/260>
12: 56 push %esi
Code; c01452bd <lock_get_status+2d/260>
13: e8 00 00 00 00 call 18 <_EIP+0x18> c01452c2
<lock_get_status+32/260>
Linux razor 2.5.36 #0 Thu Sep 19 09:32:59 EST 2002 i686 unknown unknown
GNU/Linux
Gnu C 3.0.4
Gnu make 3.79.1
util-linux 2.11n
mount 2.11n
modutils 2.4.15
e2fsprogs 1.27
Linux C Library 2.2.5
Dynamic linker (ldd) 2.2.5
Procps 2.0.7
Net-tools 1.60
Console-tools 0.2.3
Sh-utils 2.0.12
--
Burton Windle [email protected]
Linux: the "grim reaper of innocent orphaned children."
from /usr/src/linux-2.4.18/init/main.c:461
[note: please cc me or linux-fsdevel when reporting file locking bugs;
i only read linux-kernel on the web and as time permits]
It looks to me like your dereference comes from this line:
if (fl->fl_file != NULL)
inode = fl->fl_file->f_dentry->d_inode;
and, if my terribly weak x86 assembler isn't deceiving me, f_dentry
is NULL. Since you can reproduce this at will, could you insert some
debugging for me?
if (fl->fl_file != NULL) {
if (fl->fl_file->f_dentry) {
inode = fl->fl_file->f_dentry->d_inode;
} else {
printk(KERN_EMERG "null dentry at %d\n", id);
}
}
That will avoid the oops, and tell us who managed to set a file lock on
a file without a dentry.
--
Revolutions do not require corporate support.