Now that the code compiles, I need some help to debug it. I used the kernel headers shipped with my distribution (Ubuntu), namely (from uname -r) 2.6.38-13-generic Everything compiles fine, without any warning. But calling insmod, immediately triggers this error (from dmesg): [ 798.129707] generic-usb 0003:413C:2101.0002: input,hidraw0: USB HID v1.11 Keyboard [Dell Dell Smart Card Reader Keyboard] on usb-0000:00:1a.0-1.2/input0 [ 1414.832761] BUG: unable to handle kernel NULL pointer dereference at 0000000000000502 [ 1414.832880] IP: [<ffffffffa00300e4>] jwnf98_gpio_init+0xe4/0x1000 [gpio_jwnf98] [ 1414.832982] PGD 20a704067 PUD 21a601067 PMD 0 [ 1414.833036] Oops: 0000 [#1] SMP [ 1414.833077] last sysfs file: /sys/devices/pci0000:00/0000:00:19.0/net/eth0/statistics/collisions [ 1414.833152] CPU 3 [ 1414.833172] Modules linked in: gpio_jwnf98(+) btrfs zlib_deflate libcrc32c ufs qnx4 hfsplus hfs minix ntfs vfat msdos fat jfs xfs exportfs reiserfs ppdev snd_hda_codec_hdmi snd_hda_codec_via snd_hda_intel snd_hda_codec snd_hwdep snd_pcm snd_seq_midi snd_rawmidi snd_seq_midi_event lm78 hwmon_vid snd_seq snd_timer snd_seq_device i915 drm_kms_helper psmouse drm i2c_algo_bit snd video soundcore snd_page_alloc serio_raw lp parport intel_ips usbhid hid firewire_ohci e1000e firewire_core crc_itu_t [ 1414.833725] [ 1414.833744] Pid: 28764, comm: insmod Not tainted 2.6.38-13-generic #54~lucid1-Ubuntu To be filled by O.E.M. To be filled by O.E.M./To be filled by O.E.M. [ 1414.833877] RIP: 0010:[<ffffffffa00300e4>] [<ffffffffa00300e4>] jwnf98_gpio_init+0xe4/0x1000 [gpio_jwnf98] [ 1414.833965] RSP: 0018:ffff880208adbf18 EFLAGS: 00010206 [ 1414.834011] RAX: ffff8801e8e8f900 RBX: ffffffffa04cf080 RCX: ffff8801e8e8f328 [ 1414.834071] RDX: 0000000000000538 RSI: 0000000000000538 RDI: ffffffff81a19438 [ 1414.834131] RBP: ffff880208adbf18 R08: 0000000000000000 R09: ffff8801e8e8f900 [ 1414.834191] R10: 0000000000000004 R11: 0000000000000001 R12: 0000000000000000 [ 1414.834251] R13: ffffffffa0030000 R14: 0000000000000003 R15: 0000000000004000 [ 1414.834312] FS: 00007fbb2f5a5700(0000) GS:ffff8800cb380000(0000) knlGS:0000000000000000 [ 1414.834380] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1414.834430] CR2: 0000000000000502 CR3: 00000002089b2000 CR4: 00000000000006e0 [ 1414.834490] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 1414.834549] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 [ 1414.834610] Process insmod (pid: 28764, threadinfo ffff880208ada000, task ffff88021bad16e0) [ 1414.834678] Stack: [ 1414.834698] ffff880208adbf48 ffffffff81002053 ffffffffa04cf080 0000000000000000 [ 1414.834775] 00000000024a7010 0000000000000003 ffff880208adbf78 ffffffff810a3d4b [ 1414.834851] 00007fff75d0d9da 00007fff75d0d9da 00000000024a7030 00000000000019db [ 1414.834927] Call Trace: [ 1414.834958] [<ffffffff81002053>] do_one_initcall+0x43/0x190 [ 1414.835011] [<ffffffff810a3d4b>] sys_init_module+0xfb/0x250 [ 1414.835062] [<ffffffff8100c082>] system_call_fastpath+0x16/0x1b [ 1414.835114] Code: c7 c7 c0 93 a1 81 e8 5c d8 03 e1 45 31 c0 48 c7 c1 24 e0 4c a0 ba 01 00 00 00 be 38 05 00 00 48 c7 c7 c0 93 a1 81 e8 3c d8 03 e1 <8a> 04 25 02 05 00 00 48 c7 c7 00 f0 4c a0 83 c8 20 88 04 25 02 [ 1414.842138] RIP [<ffffffffa00300e4>] jwnf98_gpio_init+0xe4/0x1000 [gpio_jwnf98] [ 1414.845597] RSP <ffff880208adbf18> [ 1414.849064] CR2: 0000000000000502 [ 1414.921662] ---[ end trace d6d694e0e28fc4ad ]--- I am not aware of any pointer dereference in the code, so it is dificult to me to figure out what is wrong. Fortunately, the system does not become unresponsive (what a nice kernel!!!). The gpio_jwnf98 is listed in lsmod, but no chip directory appears under /sys/class/gpio. Finally, the module can not be removed, rmmod outputs: ERROR: Module gpio_jwnf98 is in use Thanks again for all the help. -- Joan Pau Beltran _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
