Hi, I received the following oops when using the loop driver on kernel 2.4.2-pre2 patched with Jens Axboe's loop4 patch. I believe it occurs because in loop.c, lo->lo_tsk is only assigned to by the loop thread when it starts up but it is possible for block requests to be sent to the loop drivers before this happens. ksymoops 2.3.7 on i486 2.4.2-pre2-loop4. Options used -V (default) -k /proc/ksyms (default) -l /proc/modules (default) -o /lib/modules/2.4.2-pre2-loop4/ (default) -m /boot/System.map-2.4.2-pre2-loop4 (specified) Feb 9 23:17:38 whitehall1-5 kernel: Unable to handle kernel NULL pointer dereference at virtual address 00000000 Feb 9 23:17:38 whitehall1-5 kernel: c01135fb Feb 9 23:17:38 whitehall1-5 kernel: *pde = 00000000 Feb 9 23:17:38 whitehall1-5 kernel: Oops: 0002 Feb 9 23:17:38 whitehall1-5 kernel: CPU: 0 Feb 9 23:17:38 whitehall1-5 kernel: EIP: 0010:[<c01135fb>] Using defaults from ksymoops -t elf32-i386 -a i386 Feb 9 23:17:38 whitehall1-5 kernel: EFLAGS: 00010046 Feb 9 23:17:38 whitehall1-5 kernel: eax: 00000000 ebx: 00000246 ecx: 00000000 edx: 00000246 Feb 9 23:17:38 whitehall1-5 kernel: esi: c38c9c20 edi: 00000000 ebp: c17fdc90 esp: c17fdc8c Feb 9 23:17:38 whitehall1-5 kernel: ds: 0018 es: 0018 ss: 0018 Feb 9 23:17:38 whitehall1-5 kernel: Process mount (pid: 1006, stackpage=c17fd000) Feb 9 23:17:38 whitehall1-5 kernel: Stack: c39ef800 00000700 c485282f c39ef800 c38c9c20 c0092000 00000000 c3269860 Feb 9 23:17:38 whitehall1-5 kernel: c1154060 c02521c0 00000000 c38c9c20 00000002 0000001c 00000700 c015e45a Feb 9 23:17:38 whitehall1-5 kernel: c0246bec 00000000 c38c9c20 c14b4000 c262a460 c17fc000 00000000 c38c9c20 Feb 9 23:17:38 whitehall1-5 kernel: Call Trace: [<c485282f>] [<c015e45a>] [<c015e4c9>] [<c015e757>] [<c01328f5>] [<c48176e0>] [<c48177b7>] Feb 9 23:17:39 whitehall1-5 kernel: [<c0173998>] [<c017b92e>] [<c0174731>] [<c0174a30>] [<c0143360>] [<c014447b>] [<c0137d36>] [<c481fb20>] Feb 9 23:17:39 whitehall1-5 kernel: [<c481f533>] [<c481fae0>] [<c01358b9>] [<c0135b14>] [<c481fb20>] [<c481fb20>] [<c01366e6>] [<c481fb20>] Feb 9 23:17:39 whitehall1-5 kernel: [<c481fb20>] [<c0136501>] [<c013689c>] [<c0108ee3>] Feb 9 23:17:39 whitehall1-5 kernel: Code: c7 01 00 00 00 00 8b 51 3c 85 d2 75 32 8d 41 3c 8b 15 a8 ef >>EIP; c01135fb <wake_up_process+b/50> <===== Trace; c485282f <[loop]loop_make_request+df/1c0> Trace; c015e45a <generic_make_request+14a/160> Trace; c015e4c9 <submit_bh+59/80> Trace; c015e757 <ll_rw_block+217/260> Trace; c01328f5 <bread+35/70> Trace; c48176e0 <[fat]fat_read_super+e0/8a0> Trace; c48177b7 <[fat]fat_read_super+1b7/8a0> Trace; c0173998 <ide_set_handler+58/60> Trace; c017b92e <do_rw_disk+de/290> Trace; c0174731 <ide_wait_stat+91/e0> Trace; c0174a30 <start_request+190/200> Trace; c0143360 <destroy_inode+30/40> Trace; c014447b <iput+16b/170> Trace; c0137d36 <blkdev_get+e6/100> Trace; c481fb20 <[vfat]vfat_fs_type+0/17> Trace; c481f533 <[vfat]vfat_read_super+23/90> Trace; c481fae0 <[vfat]vfat_dir_inode_operations+0/40> Trace; c01358b9 <read_super+f9/170> Trace; c0135b14 <get_sb_bdev+164/1c0> Trace; c481fb20 <[vfat]vfat_fs_type+0/17> Trace; c481fb20 <[vfat]vfat_fs_type+0/17> Trace; c01366e6 <do_mount+186/2c0> Trace; c481fb20 <[vfat]vfat_fs_type+0/17> Trace; c481fb20 <[vfat]vfat_fs_type+0/17> Trace; c0136501 <copy_mount_options+51/b0> Trace; c013689c <sys_mount+7c/c0> Trace; c0108ee3 <system_call+33/40> Code; c01135fb <wake_up_process+b/50> 00000000 <_EIP>: Code; c01135fb <wake_up_process+b/50> <===== 0: c7 01 00 00 00 00 movl $0x0,(%ecx) <===== Code; c0113601 <wake_up_process+11/50> 6: 8b 51 3c mov 0x3c(%ecx),%edx Code; c0113604 <wake_up_process+14/50> 9: 85 d2 test %edx,%edx Code; c0113606 <wake_up_process+16/50> b: 75 32 jne 3f <_EIP+0x3f> c011363a <wake_up_process+4a/50> Code; c0113608 <wake_up_process+18/50> d: 8d 41 3c lea 0x3c(%ecx),%eax Code; c011360b <wake_up_process+1b/50> 10: 8b 15 a8 ef 00 00 mov 0xefa8,%edx - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] Please read the FAQ at http://www.tux.org/lkml/