Hello, I am using the cdc_acm driver to control a few 3G mobile modem. When we do ppp calls on it, it frequently crashs the USB portion of the kernel. The machine is still usable but any process related the USB show "Ds" mode. I attache the error below. It happens ed bother 2.6.11 and 2.6.15 kernel on Fedora 4. But Debian with 2.6.13 kernel seems stable. I will be very grateful if you can point me to how to prevent it. Thanks, Simon ========= Jun 15 21:15:51 gcarc031 kernel: Unable to handle kernel NULL pointer dereference at virtual address 0000000c Jun 15 21:15:51 gcarc031 kernel: printing eip: Jun 15 21:15:51 gcarc031 kernel: c01968e2 Jun 15 21:15:51 gcarc031 kernel: *pde = 00000000 Jun 15 21:15:51 gcarc031 kernel: Oops: 0000 [#1] Jun 15 21:15:51 gcarc031 kernel: last sysfs file: /class/net/ppp0/ifindex Jun 15 21:15:51 gcarc031 kernel: Modules linked in: ppp_async crc_ccitt ppp_generic slhc ipv6 autofs4 sunrpc dm_ mod video button battery ac cdc_acm(U) uhci_hcd ohci_hcd hw_random i2c_i801 i2c_core snd_intel8x0 snd_ac97_codec snd_ac97_bus snd_seq_dummy snd_seq_oss snd_seq_midi_event snd_seq snd_seq_device snd_pcm_oss snd_mixer_oss snd_ pcm snd_timer snd soundcore snd_page_alloc 3c59x mii floppy ext3 jbd Jun 15 21:15:51 gcarc031 kernel: CPU: 0 Jun 15 21:15:51 gcarc031 kernel: EIP: 0060:[<c01968e2>] Not tainted VLI Jun 15 21:15:51 gcarc031 kernel: EFLAGS: 00010246 (2.6.15-1.1831_FC4) Jun 15 21:15:51 gcarc031 kernel: EIP is at sysfs_hash_and_remove+0x37/0x101 Jun 15 21:15:51 gcarc031 kernel: eax: 00000246 ebx: d831be50 ecx: f7ff7840 edx: 00000063 Jun 15 21:15:51 gcarc031 kernel: esi: 00000000 edi: f6d54d60 ebp: f7ffb460 esp: d8470e98 Jun 15 21:15:51 gcarc031 kernel: ds: 007b es: 007b ss: 0068 Jun 15 21:15:51 gcarc031 kernel: Process dserver7v15 (pid: 24593, threadinfo=d8470000 task=d6ed3570) Jun 15 21:15:51 gcarc031 kernel: Stack: f6d54d60 f6774928 cad6ccd8 f6f828c8 f6f828c0 f6d54d60 f7ffb460 c024f5ec Jun 15 21:15:51 gcarc031 kernel: 00000000 f7ffb4ec f6f828c0 f603b674 ea5c9164 00000000 c024f64a cb3918e0 Jun 15 21:15:51 gcarc031 kernel: f893a516 cb3918e0 f893a5f7 f603b674 ea5c9164 cedf3000 c0228d66 c0316c51 Jun 15 21:15:51 gcarc031 kernel: Call Trace: Jun 15 21:15:51 gcarc031 kernel: [<c024f5ec>] class_device_del+0xb5/0x10b [<c024f64a>] class_device_unregis ter+0x8/0x10 Jun 15 21:15:51 gcarc031 kernel: [<f893a516>] acm_tty_unregister+0x13/0x4c [cdc_acm] [<f893a5f7>] acm_tty_c lose+0xa8/0xaa [cdc_acm] Jun 15 21:15:51 gcarc031 kernel: [<c0228d66>] release_dev+0x151/0x72d [<c0316c51>] _spin_unlock_irq+0x5/0x7 Jun 15 21:15:51 gcarc031 kernel: [<c0120d52>] do_setitimer+0x19c/0x66f [<c013c3a4>] audit_syscall_entry+0x1 0b/0x15e Jun 15 21:15:51 gcarc031 kernel: [<c0316c51>] _spin_unlock_irq+0x5/0x7 [<c02297db>] tty_release+0x7/0xa Jun 15 21:15:51 gcarc031 kernel: [<c015bfbc>] __fput+0xb0/0x16e [<c015a8df>] filp_close+0x3e/0x62 Jun 15 21:15:51 gcarc031 kernel: [<c0102e75>] syscall_call+0x7/0xb Jun 15 21:15:51 gcarc031 kernel: Code: 14 24 8b 70 60 8b 58 18 85 db 0f 84 82 00 00 00 ba 63 00 00 00 b8 ea e1 3 2 c0 e8 5a 3f f8 ff ff 8b 80 00 00 00 0f 88 ca 00 00 00 <8b> 46 0c 8d 68 fc 8b: 89 74 24 Continuing in 113 seconds. rnel: Continuing in 120 seconds. Continuing in 104 seconds. Continuing in 95 seconds. Continuing in 85 seconds. Co Continuing in 77 seconds. ernel: tinuing in 84 seconds. Continuing in 67 seconds. Continuing in 58 seconds. Continuing in 48 seconds. ds. Continuing in 40 seconds. ernel: tinuing in 47 seconds. Continuing in 30 seconds. Continuing in 21 seconds. -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
