[hylafax-users] faxgetty segfault: Kernel NULL pointer dereference

["Scott Spearman" <scott.spearman@xxxxxxxxxxxxxxxxxxxxx>]

Hello,

I'm currently running Hylafax 4.2.5 on a SUSE 10.0 box (kernel version 
2.6.13-15).

Right now I'm running in a mostly send enviroment, with a Digi Rapidport 4 
USB modem bank (one USB box with 4 modems).  It will work well for a while, 
then I'll have lines start getting stuck in "Waiting for the modem to come 
free".  When this happens I can try restart faxgetty and it will do 
exactally the same thing.  The only solutions I've found are unplugging and 
replugging the modem (which moves them from ttyUSB0-ttyUSB3 to 
ttyUSB4-ttyUSB7, which is not really acceptable) or to restart the machine. 
Upon restart all four lines will be up and running.

It seems like the lock seems to be more likely after a failed send (eg Busy 
Signal or No Carrier) but I can't pin down the locks to only after these 
events.  When a line does lock, I can go out to /var/lock and find a 
LCK..ttyUSB0 file, with a PID in it.  As faxgetty restarts it seems like the 
PID in the file is usually about 1 restart of faxgetty behind, but it's hard 
to tell, as it respawns fairly quick (faxgetty is listed in inittab as a 
respawn).

The interesting bit is if I go look at /var/log/messages while it's 
restarting I get the following entries:
Nov  8 12:07:37 linuxfax FaxGetty[24856]: OPEN /dev/ttyUSB3  HylaFAX (tm) 
Version 4.2.5
Nov  8 12:07:37 linuxfax FaxGetty[24856]: Purge stale UUCP lock 
/var/lock/LCK..ttyUSB3
Nov  8 12:07:38 linuxfax kernel:  <1>Unable to handle kernel NULL pointer 
dereference at virtual address 00000090
Nov  8 12:07:38 linuxfax kernel:  printing eip:
Nov  8 12:07:38 linuxfax kernel: f97d6ea6
Nov  8 12:07:38 linuxfax kernel: *pde = 00000000
Nov  8 12:07:38 linuxfax kernel: Oops: 0000 [#40]
Nov  8 12:07:38 linuxfax kernel: SMP
Nov  8 12:07:38 linuxfax kernel: Modules linked in: hfsplus vfat fat subfs 
speedstep_lib freq_table edd snd_pcm_oss snd_mixer_oss snd_seq 
snd_seq_device button battery ac ipv6 io_edgeport usbserial usbhid 
snd_intel8x0 snd_ac97_codec i2c_i801 i2c_core tg3 snd_ac97_bus generic 
snd_pcm snd_timer snd soundcore snd_page_alloc ehci_hcd uhci_hcd intel_agp 
agpgart hw_random usbcore pci_hotplug parport_pc lp parport dm_mod reiserfs 
fan thermal sg processor ide_cd cdrom ata_piix libata piix sd_mod scsi_mod 
ide_disk ide_core
Nov  8 12:07:38 linuxfax kernel: CPU:    0
Nov  8 12:07:38 linuxfax kernel: EIP:    0060:[<f97d6ea6>]    Not tainted 
VLI
Nov  8 12:07:38 linuxfax kernel: EFLAGS: 00010246   (2.6.13-15-smp)
Nov  8 12:07:38 linuxfax kernel: EIP is at serial_tiocmset+0x26/0xe0 
[usbserial]
Nov  8 12:07:38 linuxfax kernel: eax: 00000000   ebx: 00000000   ecx: 
00000000   edx: f64b2a80
Nov  8 12:07:38 linuxfax kernel: esi: f1de8000   edi: 00000000   ebp: 
f64b2a80   esp: f57bbf34
Nov  8 12:07:38 linuxfax kernel: ds: 007b   es: 007b   ss: 0068
Nov  8 12:07:38 linuxfax kernel: Process faxgetty (pid: 24856, 
threadinfo=f57ba000 task=f5924540)
Nov  8 12:07:38 linuxfax kernel: Stack: 00000000 08076000 f23f8d84 c03b2580 
f97d6e80 f1de8000 f64b2a80 00005417
Nov  8 12:07:38 linuxfax kernel:        c026d545 00000002 c03b2580 f64b2a80 
bf89d8fc c018446a bf89d8fc fffffff7
Nov  8 12:07:38 linuxfax kernel:        f64b2a80 00000007 bf89d8fc c0184630 
f654ddfc f654dddc fffffff7 f64b2a80
Nov  8 12:07:38 linuxfax kernel: Call Trace:
Nov  8 12:07:38 linuxfax kernel:  [<f97d6e80>] serial_tiocmset+0x0/0xe0 
[usbserial]
Nov  8 12:07:38 linuxfax kernel:  [<c026d545>] tty_tiocmset+0x55/0xa0
Nov  8 12:07:38 linuxfax kernel:  [<c018446a>] do_ioctl+0x8a/0xa0
Nov  8 12:07:38 linuxfax kernel:  [<c0184630>] vfs_ioctl+0x60/0x210
Nov  8 12:07:38 linuxfax kernel:  [<c018482a>] sys_ioctl+0x4a/0xa0
Nov  8 12:07:38 linuxfax kernel:  [<c01042ab>] sysenter_past_esp+0x54/0x79
Nov  8 12:07:38 linuxfax kernel: Code: ff ff eb 86 90 83 ec 20 89 7c 24 18 
89 cf 89 6c 24 1c 89 d5 89 5c 24 10 89 74 24 14 8b 98 8c 09 00 00 a1 04 e5 
7d f9 85 c0 75 5f <8b> 8b 90 00 00 00 85 c9 75 23 8b 15 04 e5 7d f9 85 d2 75 
76 b8
Nov  8 12:07:39 linuxfax FaxGetty[5304]: MODEM LT V.90 1.0 RAPIDPORT USB 
DATA/FAX MODEM VERSION 4.25F LT V.90 1.0 Rapidport USB Data/Fax Modem 
Version 4.25f/

If I try restart faxgetty on that line by hand I get, as expected, a 
Segmentation Fault.
Does anyone have any suggestions on what's going wrong, and how I can fix 
it?  Also, can anyone send me a sample config file for the Digi Rapidport/4 
devices that I can compare against the one I have?

Thanks preemptively for all the help, and I'm sorry for the sizable first 
post!
Scott Spearman
Programmer
Pikeville Medical Center
scott.spearman@xxxxxxxxxxxxxxxxxxxxx
Phone: (606) 218-4660 


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