Alan Cox <alan@xxxxxxxxxxxxxxxxxxx> writes: >> As it stands today ftdi_sio does indeed call tty_flip_buffer_push from >> interrupt context with low_latency set and that is obviously incorrect, >> right? > > It seems to do it from a work queue - or did I miss a case ? ftdi_sio crash quite regularly for me with 2.6.31. With a bunch of nasties like: BUG: scheduling while atomic: swapper/0/0x00010000 bad: scheduling from the idle thread! I don't know if I have a good backtrace as things scrolled away faster than they were captured but the code below looks like it may be. Eric BUG: scheduling while atomic: swapper/0/0x00010000 Modules linked in: nfsd lockd nfs_acl auth_rpcgss exportfs sco bridge stp bnep l2cap bluetooth sunrpc ipv6 cpufreq_ondemand powernow_k8 freq_table dm_mirror dm_region_hash dm_log dm_multipath dm_mod uinput kvm_amd kvm fuse xt_multiport iptable_nat ip_tables nf_nat x_tables nf_conntrack_ipv4 nf_conntrack nf_defrag_ipv4 tun 8021q snd_hda_codec_realtek snd_hda_intel snd_hda_codec snd_hwdep snd_pcm snd_timer snd amd64_edac_mod firewire_ohci firewire_core soundcore i2c_nforce2 k8temp sg edac_core hwmon pcspkr sata_sil24 pata_amd snd_page_alloc e1000e forcedeth crc_itu_t i2c_core ftdi_sio usbserial ata_generic pata_acpi sata_nv libata sd_mod scsi_mod ext3 jbd mbcache uhci_hcd ohci_hcd ehci_hcd [last unloaded: scsi_wait_scan] CPU 0: Modules linked in: nfsd lockd nfs_acl auth_rpcgss exportfs sco bridge stp bnep l2cap bluetooth sunrpc ipv6 cpufreq_ondemand powernow_k8 freq_table dm_mirror dm_region_hash dm_log dm_multipath dm_mod uinput kvm_amd kvm fuse xt_multiport iptable_nat ip_tables nf_nat x_tables nf_conntrack_ipv4 nf_conntrack nf_defrag_ipv4 tun 8021q snd_hda_codec_realtek snd_hda_intel snd_hda_codec snd_hwdep snd_pcm snd_timer snd amd64_edac_mod firewire_ohci firewire_core soundcore i2c_nforce2 k8temp sg edac_core hwmon pcspkr sata_sil24 pata_amd snd_page_alloc e1000e forcedeth crc_itu_t i2c_core ftdi_sio usbserial ata_generic pata_acpi sata_nv libata sd_mod scsi_mod ext3 jbd mbcache uhci_hcd ohci_hcd ehci_hcd [last unloaded: scsi_wait_scan] Pid: 0, comm: swapper Not tainted 2.6.31-185494.2008.AroraEbiederm.fc11.x86_64 #1 RIP: 0010:[<ffffffff8102c86c>] [<ffffffff8102c86c>] native_safe_halt+0x6/0x8 RSP: 0018:ffffffff81541e48 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffffffff81541e48 RCX: 0000000003000000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffffff81541e58 RBP: ffffffff8100c7ce R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: ffff880038d0fef8 R12: ffffffff81073a1f R13: ffffffff81541dd8 R14: ffffffff8105c8d7 R15: ffffffff81541e38 FS: 00007fe289d71910(0000) GS:ffff8800017ba000(0000) knlGS:0000000000000000 CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b CR2: 0000000000404070 CR3: 000000003b87d000 CR4: 00000000000006f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: [<ffffffff81014126>] ? default_idle+0x51/0x8b [<ffffffff81014265>] ? c1e_idle+0x105/0x120 [<ffffffff8100ae15>] ? cpu_idle+0xb0/0xf3 [<ffffffff81392135>] ? rest_init+0x79/0x8f [<ffffffff815c8fae>] ? start_kernel+0x3dc/0x3fd [<ffffffff815c82d4>] ? x86_64_start_reservations+0xbb/0xd6 [<ffffffff815c83f4>] ? x86_64_start_kernel+0x105/0x128 bad: scheduling from the idle thread! Pid: 0, comm: swapper Not tainted 2.6.31-185494.2008.AroraEbiederm.fc11.x86_64 #1 Call Trace: <IRQ> [<ffffffff81041261>] dequeue_task_idle+0x37/0x5a [<ffffffff81040a23>] dequeue_task+0xce/0xf0 [<ffffffff81040a7c>] deactivate_task+0x37/0x56 [<ffffffff813a4fb7>] schedule+0x13d/0x6f3 [<ffffffff81042b82>] ? enqueue_task_fair+0xdf/0x13c [<ffffffff810404df>] ? enqueue_task+0x6f/0x91 [<ffffffff813a5e87>] __mutex_lock_common+0x12f/0x1aa [<ffffffff813a5f29>] __mutex_lock_slowpath+0x27/0x3d [<ffffffff813a5c3d>] mutex_lock+0x25/0x53 [<ffffffff81253ff9>] tty_unthrottle+0x29/0x6d [<ffffffff8125298a>] reset_buffer_flags+0xe8/0x105 [<ffffffff812529cb>] n_tty_flush_buffer+0x24/0x97 [<ffffffff8125367b>] n_tty_receive_buf+0xc3d/0xe72 [<ffffffff8129b0fd>] ? usb_hcd_submit_urb+0x888/0x943 [<ffffffff81254e83>] ? tty_ldisc_try+0x53/0x71 [<ffffffff81255f85>] flush_to_ldisc+0x116/0x1bd [<ffffffff8125608a>] tty_flip_buffer_push+0x5e/0x85 [<ffffffffa010a0ab>] ftdi_process_read+0x481/0x627 [ftdi_sio] [<ffffffffa0001aea>] ? timer_action+0x63/0x79 [ehci_hcd] [<ffffffffa010a480>] ftdi_read_bulk_callback+0x22f/0x25a [ftdi_sio] [<ffffffff81040e89>] ? complete+0x54/0x73 [<ffffffffa000597f>] ? ehci_irq+0x351/0x391 [ehci_hcd] [<ffffffff81299a32>] usb_hcd_giveback_urb+0x9b/0xe5 [<ffffffffa00010f9>] ehci_urb_done+0x91/0xbc [ehci_hcd] [<ffffffffa00027f3>] qh_completions+0x42a/0x4ca [ehci_hcd] [<ffffffffa0002938>] ehci_work+0xa5/0x7ab [ehci_hcd] [<ffffffffa00db90f>] ? nv_swncq_interrupt+0x6a3/0x6d1 [sata_nv] [<ffffffffa000597f>] ehci_irq+0x351/0x391 [ehci_hcd] [<ffffffff81073641>] ? clocksource_read+0x1d/0x33 [<ffffffff81073a1f>] ? getnstimeofday+0x69/0xd3 [<ffffffff8129933c>] usb_hcd_irq+0x4d/0xa1 [<ffffffff810a2553>] handle_IRQ_event+0x6a/0x13f [<ffffffff810a4613>] handle_fasteoi_irq+0x90/0xe1 [<ffffffff8100eb5a>] handle_irq+0x95/0xb7 [<ffffffff8100df49>] do_IRQ+0x6a/0xe0 [<ffffffff8100c7d3>] ret_from_intr+0x0/0x11 <EOI> [<ffffffff8102c86c>] ? native_safe_halt+0x6/0x8 [<ffffffff81014126>] ? default_idle+0x51/0x8b [<ffffffff81014265>] ? c1e_idle+0x105/0x120 [<ffffffff8100ae15>] ? cpu_idle+0xb0/0xf3 [<ffffffff81392135>] ? rest_init+0x79/0x8f [<ffffffff815c8fae>] ? start_kernel+0x3dc/0x3fd [<ffffffff815c82d4>] ? x86_64_start_reservations+0xbb/0xd6 [<ffffffff815c83f4>] ? x86_64_start_kernel+0x105/0x128 BUG: scheduling while atomic: swapper/0/0x00010000 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
