• Stefan Richter's avatar
    firewire: fix crash in automatic module unloading · 855c603d
    Stefan Richter authored
    "modprobe firewire-ohci; sleep .1; modprobe -r firewire-ohci" used to
    result in crashes like this:
    
        BUG: unable to handle kernel paging request at ffffffff8807b455
        IP: [<ffffffff8807b455>]
        PGD 203067 PUD 207063 PMD 7c170067 PTE 0
        Oops: 0010 [1] PREEMPT SMP
        CPU 0
        Modules linked in: i915 drm cpufreq_ondemand acpi_cpufreq freq_table applesmc input_polldev led_class coretemp hwmon eeprom snd_seq_oss snd_seq_midi_event snd_seq snd_seq_device snd_pcm_oss snd_mixer_oss button thermal processor sg snd_hda_intel snd_pcm snd_timer snd snd_page_alloc sky2 i2c_i801 rtc [last unloaded: crc_itu_t]
        Pid: 9, comm: events/0 Not tainted 2.6.25-rc2 #3
        RIP: 0010:[<ffffffff8807b455>]  [<ffffffff8807b455>]
        RSP: 0018:ffff81007dcdde88  EFLAGS: 00010246
        RAX: ffff81007dc95040 RBX: ffff81007dee5390 RCX: 0000000000005e13
        RDX: 0000000000008c8b RSI: 0000000000000001 RDI: ffff81007dee5388
        RBP: ffff81007dc5eb40 R08: 0000000000000002 R09: ffffffff8022d05c
        R10: ffffffff8023b34c R11: ffffffff8041a353 R12: ffff81007dee5388
        R13: ffffffff8807b455 R14: ffffffff80593bc0 R15: 0000000000000000
        FS:  0000000000000000(0000) GS:ffffffff8055a000(0000) knlGS:0000000000000000
        CS:  0010 DS: 0018 ES: 0018 CR0: 000000008005003b
        CR2: ffffffff8807b455 CR3: 0000000000201000 CR4: 00000000000006e0
        DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
        DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
        Process events/0 (pid: 9, threadinfo ffff81007dcdc000, task ffff81007dc95040)
        Stack:  ffffffff8023b396 ffffffff88082524 0000000000000000 ffffffff8807d9ae
        ffff81007dc5eb40 ffff81007dc9dce0 ffff81007dc5eb40 ffff81007dc5eb80
        ffff81007dc9dce0 ffffffffffffffff ffffffff8023be87 0000000000000000
        Call Trace:
        [<ffffffff8023b396>] ? run_workqueue+0xdf/0x1df
        [<ffffffff8023be87>] ? worker_thread+0xd8/0xe3
        [<ffffffff8023e917>] ? autoremove_wake_function+0x0/0x2e
        [<ffffffff8023bdaf>] ? worker_thread+0x0/0xe3
        [<ffffffff8023e813>] ? kthread+0x47/0x74
        [<ffffffff804198e0>] ? trace_hardirqs_on_thunk+0x35/0x3a
        [<ffffffff8020c008>] ? child_rip+0xa/0x12
        [<ffffffff8020b6e3>] ? restore_args+0x0/0x3d
        [<ffffffff8023e68a>] ? kthreadd+0x14c/0x171
        [<ffffffff8023e68a>] ? kthreadd+0x14c/0x171
        [<ffffffff8023e7cc>] ? kthread+0x0/0x74
        [<ffffffff8020bffe>] ? child_rip+0x0/0x12
    
        Code:  Bad RIP value.
        RIP  [<ffffffff8807b455>]
        RSP <ffff81007dcdde88>
        CR2: ffffffff8807b455
        ---[ end trace c7366c6657fe5bed ]---
    
    Note that this crash happened _after_ firewire-core was unloaded.  The
    shared workqueue tried to run firewire-core's device initialization jobs
    or similar jobs.
    
    The fix makes sure that firewire-ohci and hence firewire-core is not
    unloaded before all device shutdown jobs have been completed.  This is
    determined by the count of device initializations minus device releases.
    
    Also skip useless retries in the node initialization job if the node is
    to be shut down.
    Signed-off-by: default avatarStefan Richter <stefanr@s5r6.in-berlin.de>
    Signed-off-by: default avatarJarod Wilson <jwilson@redhat.com>
    855c603d
fw-sbp2.c 45.4 KB