On Mon, Aug 4, 2008 at 6:00 PM, Jiri Slaby [off-list ref] wrote:

Dave Young napsal(a):

quoted

Lockdep helped me, this morning I get a lockdep warning about this,

[  171.432140] [ INFO: possible recursive locking detected ]
[  171.433113] 2.6.27-rc1-smp #4
[  171.434079] ---------------------------------------------
[  171.435039] ath5k_pci/2447 is trying to acquire lock:
[  171.435990]  (&sc->lock){--..}, at: [<f89ee9b5>]
ath5k_config_interface+0xd5/0x340 [ath5k]
[  171.437046]
[  171.437048] but task is already holding lock:
[  171.438903]  (&sc->lock){--..}, at: [<f89ee91d>]
ath5k_config_interface+0x3d/0x340 [ath5k]
[  171.439953]
[  171.439954] other info that might help us debug this:
[  171.441795] 3 locks held by ath5k_pci/2447:
[  171.442729]  #0:  ((name)){--..}, at: [<c013a122>]
run_workqueue+0x102/0x1d0
[  171.443800]  #1:  (&(&local->scan_work)->work){--..}, at:
[<c013a122>] run_workqueue+0x102/0x1d0
[  171.444859]  #2:  (&sc->lock){--..}, at: [<f89ee91d>]
ath5k_config_interface+0x3d/0x340 [ath5k]

Deadlock happen here, I remove the lock in the sub routine, tested and
fixed the problem for me.
I will send the patch after a while.

That's some kind different. 2.6.26 can't suffer from the thing above
(opposing to 27-rc1).

Yes, it's got with 27-rc1

Pasting the original issue below. Maybe it's been fixed too? I suppose you
don't encounter the problem anymore in 27-rc1 with your/Bob's/mine (fix for
the same thing in the same manner) patch applied?

With the patch I cann't reproduce the bug with 27-rc1 now.

BUG: soft lockup - CPU#0 stuck for 61s! [events/0:9]
Modules linked in: radeonfb fb_ddc i2c_algo_bit snd_seq_dummy snd_seq_oss
snd_seq_midi_event snd_seq snd_seq_device snd_pcm_oss snd_mixer_oss rfcomm
l2cap bluetooth vfat fuse rtc_cmos rtc_core psmouse intel_agp pl2303 rtc_lib
ath5k e100 i2c_i801 serio_raw usbserial agpgart 3c59x mii snd_hda_intel
snd_pcm mac80211 snd_timer snd_page_alloc cfg80211 snd_hwdep snd soundcore
thermal processor button thermal_sys evdev sg

Pid: 9, comm: events/0 Tainted: G        W (2.6.26-smp #3)
EIP: 0060:[<c0450bc3>] EFLAGS: 00000246 CPU: 0
EIP is at mutex_lock_nested+0x1b3/0x280
EAX: 00000000 EBX: f7bf5284 ECX: f7c7e000 EDX: f7bf52a8
ESI: f7bf5288 EDI: 00000246 EBP: f7c7fedc ESP: f7c7fe9c
 DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
CR0: 8005003b CR2: b800c5ac CR3: 36e71000 CR4: 000006d0
DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
DR6: ffff0ff0 DR7: 00000400
 [<c02375a6>] ? debugfs_create_file+0x46/0x210
 [<c02375a6>] ? debugfs_create_file+0x46/0x210
 [<c02375a6>] debugfs_create_file+0x46/0x210
 [<c02377f1>] debugfs_create_dir+0x21/0x30
 [<f8901f6d>] ieee80211_sta_debugfs_add+0x2d/0x150 [mac80211]
 [<f88eba89>] sta_info_debugfs_add_work+0x89/0x130 [mac80211]
 [<f890a170>] ? rate_control_pid_add_sta_debugfs+0x0/0x30 [mac80211]
 [<c01394c6>] run_workqueue+0x156/0x1d0
 [<c0139472>] ? run_workqueue+0x102/0x1d0
 [<f88eba00>] ? sta_info_debugfs_add_work+0x0/0x130 [mac80211]
 [<c0139f18>] worker_thread+0x88/0xe0
 [<c013cd20>] ? autoremove_wake_function+0x0/0x40
 [<c0139e90>] ? worker_thread+0x0/0xe0
 [<c013ca32>] kthread+0x42/0x70
 [<c013c9f0>] ? kthread+0x0/0x70
 [<c0104993>] kernel_thread_helper+0x7/0x14
 =======================
BUG: soft lockup - CPU#0 stuck for 61s! [events/0:9]
Modules linked in: radeonfb fb_ddc i2c_algo_bit snd_seq_dummy snd_seq_oss
snd_seq_midi_event snd_seq snd_seq_device snd_pcm_oss snd_mixer_oss rfcomm
l2cap bluetooth vfat fuse rtc_cmos rtc_core psmouse intel_agp pl2303 rtc_lib
ath5k e100 i2c_i801 serio_raw usbserial agpgart 3c59x mii snd_hda_intel
snd_pcm mac80211 snd_timer snd_page_alloc cfg80211 snd_hwdep snd soundcore
thermal processor button thermal_sys evdev sg

Pid: 9, comm: events/0 Tainted: G        W (2.6.26-smp #3)
EIP: 0060:[<c0450bc3>] EFLAGS: 00000246 CPU: 0
EIP is at mutex_lock_nested+0x1b3/0x280
EAX: 00000000 EBX: f7bf5284 ECX: f7c7e000 EDX: f7bf52a8
ESI: f7bf5288 EDI: 00000246 EBP: f7c7fedc ESP: f7c7fe9c
 DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
CR0: 8005003b CR2: b800c5ac CR3: 36e71000 CR4: 000006d0
DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
DR6: ffff0ff0 DR7: 00000400
 [<c02375a6>] ? debugfs_create_file+0x46/0x210
 [<c02375a6>] ? debugfs_create_file+0x46/0x210
 [<c02375a6>] debugfs_create_file+0x46/0x210
 [<c02377f1>] debugfs_create_dir+0x21/0x30
 [<f8901f6d>] ieee80211_sta_debugfs_add+0x2d/0x150 [mac80211]
 [<f88eba89>] sta_info_debugfs_add_work+0x89/0x130 [mac80211]
 [<f890a170>] ? rate_control_pid_add_sta_debugfs+0x0/0x30 [mac80211]
 [<c01394c6>] run_workqueue+0x156/0x1d0
 [<c0139472>] ? run_workqueue+0x102/0x1d0
 [<f88eba00>] ? sta_info_debugfs_add_work+0x0/0x130 [mac80211]
 [<c0139f18>] worker_thread+0x88/0xe0
 [<c013cd20>] ? autoremove_wake_function+0x0/0x40
 [<c0139e90>] ? worker_thread+0x0/0xe0
 [<c013ca32>] kthread+0x42/0x70
 [<c013c9f0>] ? kthread+0x0/0x70
 [<c0104993>] kernel_thread_helper+0x7/0x14
 =======================

-- 
Regards
dave