On Fri, 23 Jan 2009, Philippe Vouters wrote:
As soon as Fedora upgrades my kernel to 2.6.28, I'll have a look at it. The latest stable Fedora 10 kernel is 2.6.27.9-159.fc10.i686. This is what I boot. Not willing to pay on my own purse for a ppp connection trial, I shall emulate this software using efax as documentked in the Intel-Readme.txt.
That's the kernel I'm using currently too, but I did keep the 2.6.28.1 around for testing later on.
You don't actually need an account, only to test the modem. You can do that by just using it to dial something using something like Minicom or Kermit. Even a regular phone number will do.
I recompiled the kmod with DEBUG_LINUX defined and tracked the error further. It certainly looks to be in softserial_open(). As soon as something calls that, the trouble starts. Since that isn't the code touched that changed from 2.6.27 to 2.6.28, likely this error crept in before but wasn't hit for some reason.
2009-01-23T20:50:37.695319-05:00 atr2 kernel:<4>softserial:init_module() 2009-01-23T20:50:37.696482-05:00 atr2 kernel:<4>softserial: venid 8086, dev 1040 2009-01-23T20:50:37.721517-05:00 atr2 kernel:<4>softserial_register_tty(): tty registered 2009-01-23T20:50:37.722185-05:00 atr2 kernel:<4>softserial: init done Module loads fine. 2009-01-23T20:52:18.836433-05:00 atr2 kernel:<4>------------[ cut here ]------------ 2009-01-23T20:52:18.837422-05:00 atr2 kernel:<4>WARNING: at lib/kref.c:43 kref_get+0x17/0x1b() 2009-01-23T20:52:18.837966-05:00 atr2 kernel:<4>Modules linked in: Intel536 ipv6 twofish_i586 twofish_common aes_i586 aes_generic msr cpuid microcode blowfish cbc cryptd md5 hangcheck_timer pcspkr ppp_generic slhc tulip parport_pc parport rtc_cmos rtc_core rtc_lib uhci_hcd ehci_hcd nfnetlink snd_dummy snd_pcm snd_timer snd snd_page_alloc soundcore configfs 2009-01-23T20:52:18.838511-05:00 atr2 kernel:<4>Pid: 1802, comm: kermit Not tainted 2.6.28.1 #1 2009-01-23T20:52:18.838957-05:00 atr2 kernel:<4>Call Trace: 2009-01-23T20:52:18.839419-05:00 atr2 kernel:<4> [<c0114808>] warn_on_slowpath+0x40/0x60 2009-01-23T20:52:18.839875-05:00 atr2 kernel:<4> [<c0164b60>] generic_write_end+0x24/0x73 2009-01-23T20:52:18.840330-05:00 atr2 kernel:<4> [<c0164ba8>] generic_write_end+0x6c/0x73 2009-01-23T20:52:18.840790-05:00 atr2 kernel:<4> [<c0132b34>] generic_file_buffered_write+0x137/0x24a 2009-01-23T20:52:18.841250-05:00 atr2 kernel:<4> [<c0132b8d>] generic_file_buffered_write+0x190/0x24a 2009-01-23T20:52:18.841756-05:00 atr2 kernel:<4> [<c0159b83>] __d_lookup+0x93/0xc1 2009-01-23T20:52:18.842210-05:00 atr2 kernel:<4> [<c0153a5a>] do_lookup+0x47/0x116 2009-01-23T20:52:18.842663-05:00 atr2 kernel:<4> [<c01afeba>] kobject_get+0xf/0x13 2009-01-23T20:52:18.843116-05:00 atr2 kernel:<4> [<c01b08c8>] kref_get+0x17/0x1b 2009-01-23T20:52:18.843568-05:00 atr2 kernel:<4> [<c01de691>] tty_open+0x120/0x353 2009-01-23T20:52:18.844018-05:00 atr2 kernel:<4> [<c014fdb5>] chrdev_open+0xdb/0xf1 2009-01-23T20:52:18.844468-05:00 atr2 kernel:<4> [<c014fcda>] chrdev_open+0x0/0xf1 2009-01-23T20:52:18.844961-05:00 atr2 kernel:<4> [<c014c9b1>] __dentry_open+0xfe/0x1e6 2009-01-23T20:52:18.845415-05:00 atr2 kernel:<4> [<c014cb16>] nameidata_to_filp+0x1c/0x2c 2009-01-23T20:52:18.845866-05:00 atr2 kernel:<4> [<c01556d8>] do_filp_open+0x33d/0x63d 2009-01-23T20:52:18.846319-05:00 atr2 kernel:<4> [<c0184ac8>] ext2_delete_entry+0x183/0x18d 2009-01-23T20:52:18.846771-05:00 atr2 kernel:<4> [<c014969e>] virt_to_head_page+0x1f/0x2a 2009-01-23T20:52:18.847222-05:00 atr2 kernel:<4> [<c0155d64>] do_unlinkat+0xcf/0xfd 2009-01-23T20:52:18.847671-05:00 atr2 kernel:<4> [<c015c09d>] alloc_fd+0x49/0xab 2009-01-23T20:52:18.848156-05:00 atr2 kernel:<4> [<c014c7b3>] do_sys_open+0x46/0xe7 2009-01-23T20:52:18.848611-05:00 atr2 kernel:<4> [<c014c898>] sys_open+0x1e/0x23 2009-01-23T20:52:18.849063-05:00 atr2 kernel:<4> [<c0102bd9>] sysenter_do_call+0x12/0x25 2009-01-23T20:52:18.849509-05:00 atr2 kernel:<4>---[ end trace 4c3a0a4d07ff0582 ]--- Below you can see kermit called softserial_open. 2009-01-23T20:52:18.849952-05:00 atr2 kernel:<4>softserial:softserial_open() 2009-01-23T20:52:18.850395-05:00 atr2 kernel:<4>softserial_open:caller kermit[1802] 2009-01-23T20:52:18.850850-05:00 atr2 kernel:<1>BUG: unable to handle kernel NULL pointer dereference at 00000001 2009-01-23T20:52:18.851307-05:00 atr2 kernel:<1>IP: [<ced9c18d>] softserial_open+0xdd/0x180 [Intel536] 2009-01-23T20:52:18.851790-05:00 atr2 kernel:<4>*pde = 00000000
