Bug 157314

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Description of problem:
When loading qla2300 with qla2300_conf, the kernel panics with the following:

Unable to handle kernel NULL pointer dereference at virtual address 0000000000000018
 printing rip:
ffffffffa00c2845
PML4 1e535067 PGD 1ffcbe067 PMD 0
Oops: 0000
CPU 0
Pid: 1377, comm: modprobe Not tainted
RIP: 0010:[<ffffffffa00c2845>]{:qla2300:qla2x00_find_matching_lun_by_num+69}
RSP: 0000:00000101ffcf9bd0  EFLAGS: 00010287
RAX: 00000101ff7ea1d0 RBX: 00000101ff7e0000 RCX: 0000000000000001
RDX: 0000000000000000 RSI: 00000101ff7ea0c0 RDI: 0000000000000000
RBP: 00000101ffc65000 R08: 0000000000000000 R09: 0000000000000001
R10: 000001020c4c6000 R11: 00000101ff7ea304 R12: 00000101ff7ea0c0
R13: 0000000000000000 R14: 0000000000000000 R15: 00000101ff7ea1c0
FS:  0000002a958cb4c0(0000) GS:ffffffff805dd4c0(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 0000000000000018 CR3: 0000000000101000 CR4: 00000000000006e0
                                                                                
Call Trace: [<ffffffffa00c2de5>]{:qla2300:qla2x00_map_a_oslun+133}
       [<ffffffffa00c2bad>]{:qla2300:qla2x00_map_or_failover_oslun+45}
       [<ffffffffa00c2d43>]{:qla2300:qla2x00_map_os_luns+291}
       [<ffffffffa00c2b42>]{:qla2300:qla2x00_map_os_targets+162}
       [<ffffffffa00c262c>]{:qla2300:qla2x00_update_mp_host+140}
       [<ffffffffa014aa10>]{:qla2300:QLBoardTbl_fc+48} [<ffffffffa00bf8d5>]{:qla2300:qla2x00_cfg_path_discovery+165}
       [<ffffffffa00bf824>]{:qla2300:qla2x00_cfg_init+52}
       [<ffffffffa00ad041>]{:qla2300:qla2x00_detect+2081}
       [<ffffffffa014ad40>]{:qla2300:driver_template+0} [<ffffffff80154e38>]{__alloc_pages+152}
       [<ffffffff8014a1ca>]{__vmalloc+442} [<ffffffffa014ad40>]{:qla2300:driver_template+0}
       [<ffffffffa0002373>]{:scsi_mod:scsi_register_host+115}
       [<ffffffffa00be3b0>]{:qla2300:init_this_scsi_driver+32}
       [<ffffffff80125fb6>]{sys_init_module+1686} [<ffffffffa00a30b8>]
       [<ffffffff80110177>]{system_call+119}
Process modprobe (pid: 1377, stackpage=101ffcf9000)
Stack: 00000101ffcf9bd0 0000000000000000 ffffffffa00c2de5 0000000000000007
       00000000000000ff 0000000000000000 0000ffff802b85e8 000001020c4c6000
       00000101ff7ea0c0 000001020c4c6000 0000000000000000 0000000000000000
       0000000000000000 000001000e318100 ffffffffa00c2bad 0000000000000001
       00000101ff7ea0c0 000001020c4c6000 0000000000000000 00000101ff7ea0c0
       ffffffffa00c2d43 0000000000000246 000001020c4c7000 00000101ff7ea0c0
       00000101ffc65000 0000000000000000 000001020c4c6000 000001000e318100
       ffffffffa00c2b42 0000000000000001 0000000000000000 000001000e318228
       000001020c4c6000 0000000000000002 000001000e318100 0000000000000001
       ffffffffa00c262c 000001020c4c6000 000001020c4c6000 000001000e318100
Call Trace: [<ffffffffa00c2de5>]{:qla2300:qla2x00_map_a_oslun+133}
       [<ffffffffa00c2bad>]{:qla2300:qla2x00_map_or_failover_oslun+45}
       [<ffffffffa00c2d43>]{:qla2300:qla2x00_map_os_luns+291}
       [<ffffffffa00c2b42>]{:qla2300:qla2x00_map_os_targets+162}
       [<ffffffffa00c262c>]{:qla2300:qla2x00_update_mp_host+140}
       [<ffffffffa014aa10>]{:qla2300:QLBoardTbl_fc+48} [<ffffffffa00bf8d5>]{:qla2300:qla2x00_cfg_path_discovery+165}
       [<ffffffffa00bf824>]{:qla2300:qla2x00_cfg_init+52}
       [<ffffffffa00ad041>]{:qla2300:qla2x00_detect+2081}
       [<ffffffffa014ad40>]{:qla2300:driver_template+0} [<ffffffff80154e38>]{__alloc_pages+152}
       [<ffffffff8014a1ca>]{__vmalloc+442} [<ffffffffa014ad40>]{:qla2300:driver_template+0}
       [<ffffffffa0002373>]{:scsi_mod:scsi_register_host+115}
       [<ffffffffa00be3b0>]{:qla2300:init_this_scsi_driver+32}
       [<ffffffff80125fb6>]{sys_init_module+1686} [<ffffffffa00a30b8>]
       [<ffffffff80110177>]{system_call+119}
                                                                                
Code: 66 41 3b 78 18 75 07 ba 01 00 00 00 eb 08 4d 8b 00 49 39 c0
                                                                                
Kernel panic: Fatal exception



Version-Release number of selected component (if applicable):
2.4.21-20.ELsmp

How reproducible:
Always

Steps to Reproduce:
Install RHEL3 U3.  Enable failover with the following in /etc/modules.conf
  options qla2300 ql2xfailover=1 ConfigRequired=1 displayConfig=1 ql2xopts=

Then configure using SANsurfer (2.0.27) from Qlogic for the Red Hat supplied 7.0.x driver (which creates qla2300_conf and changes the option line to read 'ql2xuseextopts=1')

I have commented out "alias scsi_hostadapter1 qla2300" and rebuilt the initrd so that qla2300 is not loaded from the initrd.  Rather, /etc/rc.modules contains:

   modprobe qla2300

That way I don't have to rebuild the initrd when the config (qla2300_conf) changes.

Now reboot the node.

When the qla2300 driver loads, the system will reliably kernel panic.


Actual Results:  Kernel panic

Expected Results:  Driver loads with failover and load balance configuration.

Additional info:

Setting mem=3000m (to limit RAM to less than 4G) did not make a difference.  (Did I say that these machines have 12G of RAM in them?)

The error happens with both 7.0.xxx (stock Red Hat EL3 U3) and 7.3.xxx (from Qlogic).

The problem is specific to use of qla2300_conf (the extended options module).  If I disable it by setting 'ConfigRequired=0' and 'ql2xuseextopts=0' while leaving 'ql2xfailover=1', then the failover config is automatically detected (without load-balance) correctly and the module does not panic.

The problem can be reliably reproduced.  It has happened on 3 different machines with identical hardware configs.