Hi Anand, On 2016년 04월 09일 03:24, Chanwoo Choi wrote: > Hi Anand, > > On Sat, Apr 9, 2016 at 3:11 AM, Anand Moon <linux.amoon@xxxxxxxxx> wrote: >> Hi Chanwoo, >> [snip] >>> >> >> I am observing following deadlock. Both on Odroid U3 and Odroid XU4. > > Thanks for your test. I'll test it again and fix it. This possible recursive locking is fixed with following diff: Thanks for your report. I'll fix it on next patchset[1] (v9). [1] https://lkml.org/lkml/2016/4/8/14 diff --git a/drivers/devfreq/governor_passive.c b/drivers/devfreq/governor_passive.c index 28a9ae32d330..a4b0b02ee797 100644 --- a/drivers/devfreq/governor_passive.c +++ b/drivers/devfreq/governor_passive.c @@ -102,7 +102,7 @@ static int update_devfreq_passive(struct devfreq *devfreq, unsigned long freq) if (!devfreq->governor) return -EINVAL; - mutex_lock(&devfreq->lock); + mutex_lock_nested(&devfreq->lock, SINGLE_DEPTH_NESTING); ret = devfreq->governor->get_target_freq(devfreq, &freq); if (ret < 0) Best Regards, Chanwoo Choi > >> >> [ 7.718372] [ INFO: possible recursive locking detected ] >> [ 7.723747] 4.6.0-rc2-xu4ml #4 Not tainted >> [ 7.727817] --------------------------------------------- >> [ 7.733190] kworker/u16:1/136 is trying to acquire lock: >> [ 7.738476] (&devfreq->lock){+.+.+.}, at: [<c05be41c>] >> update_devfreq_passive+0x2c/0x88 >> [ 7.746534] >> [ 7.746534] but task is already holding lock: >> [ 7.752339] (&devfreq->lock){+.+.+.}, at: [<c05bd838>] >> devfreq_monitor+0x1c/0x78 >> [ 7.759791] >> [ 7.759791] other info that might help us debug this: >> [ 7.766291] Possible unsafe locking scenario: >> [ 7.766291] >> [ 7.766307] usb 5-1: new high-speed USB device number 2 using xhci-hcd >> [ 7.778682] CPU0 >> [ 7.781107] ---- >> [ 7.783533] lock(&devfreq->lock); >> [ 7.786999] lock(&devfreq->lock); >> [ 7.790467] >> [ 7.790467] *** DEADLOCK *** >> [ 7.790467] >> [ 7.796359] May be due to missing lock nesting notation >> [ 7.796359] >> [ 7.803120] 4 locks held by kworker/u16:1/136: >> [ 7.807537] #0: ("%s"("devfreq_wq")){.+.+..}, at: [<c013b41c>] >> process_one_work+0x13c/0x454 >> [ 7.816029] #1: ((&(&devfreq->work)->work)){+.+...}, at: >> [<c013b41c>] process_one_work+0x13c/0x454 >> [ 7.825128] #2: (&devfreq->lock){+.+.+.}, at: [<c05bd838>] >> devfreq_monitor+0x1c/0x78 >> [ 7.833013] #3: (&nh->srcu){......}, at: [<c014309c>] >> __srcu_notifier_call_chain+0x54/0xe0 >> [ 7.841419] >> [ 7.841419] stack backtrace: >> [ 7.845758] CPU: 1 PID: 136 Comm: kworker/u16:1 Not tainted >> 4.6.0-rc2-xu4ml #4 >> [ 7.852946] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) >> [ 7.859017] Workqueue: devfreq_wq devfreq_monitor >> [ 7.863717] [<c010eb48>] (unwind_backtrace) from [<c010b884>] >> (show_stack+0x10/0x14) >> [ 7.871417] [<c010b884>] (show_stack) from [<c037715c>] >> (dump_stack+0xa4/0xd0) >> [ 7.878613] [<c037715c>] (dump_stack) from [<c017112c>] >> (__lock_acquire+0x1ce8/0x207c) >> [ 7.886492] [<c017112c>] (__lock_acquire) from [<c0172010>] >> (lock_acquire+0x90/0xd4) >> [ 7.892726] usb 5-1: New USB device found, idVendor=0bda, idProduct=8153 >> [ 7.892737] usb 5-1: New USB device strings: Mfr=1, Product=2, SerialNumber=6 >> [ 7.892745] usb 5-1: Product: USB 10/100/1000 LAN >> [ 7.892753] usb 5-1: Manufacturer: Realtek >> [ 7.892761] usb 5-1: SerialNumber: 000001000000 >> [ 7.921248] [<c0172010>] (lock_acquire) from [<c075d298>] >> (mutex_lock_nested+0x78/0x4ec) >> [ 7.929301] [<c075d298>] (mutex_lock_nested) from [<c05be41c>] >> (update_devfreq_passive+0x2c/0x88) >> [ 7.938138] [<c05be41c>] (update_devfreq_passive) from [<c05be4c0>] >> (devfreq_passive_notifier_call+0x48/0x50) >> [ 7.948016] [<c05be4c0>] (devfreq_passive_notifier_call) from >> [<c0142d84>] (notifier_call_chain+0x54/0xa4) >> [ 7.957633] [<c0142d84>] (notifier_call_chain) from [<c01430e0>] >> (__srcu_notifier_call_chain+0x98/0xe0) >> [ 7.966991] [<c01430e0>] (__srcu_notifier_call_chain) from >> [<c0143140>] (srcu_notifier_call_chain+0x18/0x20) >> [ 7.976783] [<c0143140>] (srcu_notifier_call_chain) from >> [<c05bd774>] (update_devfreq+0xe4/0x18c) >> [ 7.985622] [<c05bd774>] (update_devfreq) from [<c05bd840>] >> (devfreq_monitor+0x24/0x78) >> [ 7.993595] [<c05bd840>] (devfreq_monitor) from [<c013b48c>] >> (process_one_work+0x1ac/0x454) >> [ 8.001913] [<c013b48c>] (process_one_work) from [<c013b784>] >> (worker_thread+0x50/0x508) >> [ 8.009976] [<c013b784>] (worker_thread) from [<c0141cf4>] >> (kthread+0xf8/0x110) >> [ 8.017254] [<c0141cf4>] (kthread) from [<c0107750>] >> (ret_from_fork+0x14/0x24) >> >> Best Regards >> -Anand Moon >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in >> the body of a message to majordomo@xxxxxxxxxxxxxxx >> More majordomo info at http://vger.kernel.org/majordomo-info.html > -- > To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > > -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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