On Sat, Mar 31, 2018 at 12:49 PM, Stefan Wahren <stefan.wahren@xxxxxxxx> wrote: > Hi, > > i build linux-next-20180327 with bcm2835_defconfig, but additionally enabled the following settings: > > CONFIG_SMP=y > CONFIG_PREEMPT=y > CONFIG_PROVE_LOCKING=y > > If i boot my RPi Zero W, then i will get the following output during hci_uart probe: I saw something similar, sorry don't have the exact bits close to hand, on the RPI3 on 4.16 when I applied the this patch [1], unfortunately I never got enough time to go back and debug it further. The description in the patch is a bit misleading too as it mentions it's specifically for the Zero W but applies the changes to thebcm283x.dtsi which affects all editions of the RPi. Peter [1] https://patchwork.kernel.org/patch/10240919/ > [ 42.245521] ====================================================== > [ 42.265953] WARNING: possible circular locking dependency detected > [ 42.286527] 4.16.0-rc7-next-20180327+ #2 Tainted: G C > [ 42.307153] ------------------------------------------------------ > [ 42.327529] kworker/u2:1/31 is trying to acquire lock: > [ 42.346819] (bcm_device_lock){+.+.}, at: [<bf07b028>] bcm_recv+0xa4/0x10c [hci_uart] > [ 42.369028] > but task is already holding lock: > [ 42.402020] (&buf->lock){+.+.}, at: [<c04ad460>] flush_to_ldisc+0x2c/0xc0 > [ 42.422713] > which lock already depends on the new lock. > > [ 42.471181] > the existing dependency chain (in reverse order) is: > [ 42.505116] > -> #3 (&buf->lock){+.+.}: > [ 42.536142] __763608] __ldsem_down_write_nested+0x4c/0x280 > [ 42.780869] ldsem_down_write+0x3c/0x48 > [ 42.797163] tty_ldisc_lock+0x20/0x44 > [ 42.813230] tty_init_dev+0xd8/0x1b0 > [ 42.829130] tty_open+0x30c/0x32c > [ 42.844633] chrdev_open+0x154/0x170 > [ 42.860303] do_dentry_open.constprop.4+0x2a8/0x320 > [ 42.877260] vfs_open+0x78/0x7c > [ 42.892198] path_openat+0xc14/0xde0 > [ 42.907367] do_filp_open+0x40/0x8c > [ 42.922270] do_sys_open+0x114/0x1c4 > [ 42.937142] kernel_init_freeable+0x12c/0x1e0 > [ 42.952797] kernel_init+0x18/0x120 > [ 42.967461] ret_from_fork+0x14/0x20 > [ 42.982195] (null) > [ 42.995444] > -> #1 (&tty->legacy_mutex){+.+.}: > [ 43.022015] __mutex_lock+0x70/0x9b4 > [ 43.036665] mutex_lock_nested+0x2c/0x34 > [ 43.051661] tty_lock+0x5c/0x6c > [ 43.065808] tty_init_dev+0x4c/0x1b0 > [ 43.080298] ttyport_open+0x34/0x14c > [ 43.094701] serdev_device_open+0x34/0x40 > [ 43.109685] bcm_open+0x9c/0x190 [hci_uart] > [ 43.124862] hci_uart_register_device+0x48/0x228 [hci_uart] > [ 43.141536] bcm_serdev_probe+0xac/0xcc [hci_uart] > [ 43.157381] serdev_drv_probe+0x20/0x24 > [ 43.172165] driver_probe_device+0x2d4/0x46c > [ 43.187363] __driver_attach+0x98/0x108 > [ 43.202081] bus_for_each_dev+0x68/0x8c > [ 43.216802] driver_attach+0x28/0x30 > [ 43.231232] driver_attach_async+0x20/0x58 > [ 43.246142] async_run_entry_fn+0x98/0x1a0 > [ 43.261105] process_one_work+0x3c8/0x76c > [ 43.276054] worker_thread+0x2b0/0x43c > [ 43.290632] kthread+0x158/0x174 > [ 43.304530] ret_from_fork+0x14/0x20 > [ 43.318693] (null) > [ 43.331378] > -> #0 (bcm_device_lock){+.+.}: > [ 43.356310] lock_acquire+0x228/0x298 > [ 43.370173] __mutex_lock+0x70/0x9b4 > [ 43.383785] mutex_lock_nested+0x2c/0x34 > [ 43.397711] bcm_recv+0xa4/0x10c [hci_uart] > [ 43.411957] hci_uart_receive_buf+0x68/0x84 [hci_uart] > [ 43.427034] ttyport_receive_buf+0x6c/0xe4 > [ 43.440958] flush_to_ldisc+0xa0/0xc0 > [ 43.454321] process_one_work+0x3c8/0x76c > [ 43.468099] worker_thread+0x2b0/0x43c > [ 43.481666] kthread+0x158/0x174 > [ 43.494633] ret_from_fork+0x14/0x20 > [ 43.507831] (null) > [ 43.519665] > other info that might help us debug this: > > [ 43.554302] Chain exists of: > bcm_device_lock --> &tty->ldisc_sem --> &buf->lock > > [ 43.591776] Possible unsafe locking scenario: > > [ 43.615986] CPU0 CPU1 > [ 43.629708] ---- ---- > [ 43.643463] lock(&buf->lock); > [ 43.655748] lock(&tty->ldisc_sem); > [ 43.671197] lock(&buf->lock); > [ 43.686220] lock(bcm_device_lock); > [ 43.699078] > *** DEADLOCK *** > > [ 43.731942] 3 locks held by kworker/u2:1/31: > [ 43.745364] #0: ((wq_completion)"events_unbound"){+.+.}, at: [<c013fb3c>] process_one_work+0x1e0/0x76c > [ 43.764636] #1: ((work_completion)(&buf->work)){+.+.}, at: [<c013fb3c>] process_one_work+0x1e0/0x76c > [ 43.783902] #2: (&buf->lock){+.+.}, at: [<c04ad460>] flush_to_ldisc+0x2c/0xc0 > [ 43.801205] > stack backtrace: > [ 43.824860] CPU: 0 PID: 31 Comm: kworker/u2:1 Tainted: G C 4.16.0-rc7-next-20180327+ #2 > [ 43.844393] Hardware name: BCM2835 > [ 43.857885] Workqueue: events_unbound flush_to_ldisc > [ 43.873103] [<c01118f4>] (unwind_backtrace) from [<c010da50>] (show_stack+0x20/0x24) > [ 43.891391] [<c010da50>] (show_stack) from [<c08f3590>] (dump_stack+0xa4/0xe0) > [ 43.909283] [<c08f3590>] (dump_stack) from [<c017d4e0>] (print_circular_bug.constprop.20+0x1dc/0x2d8) > [ 43.929391] [<c017d4e0>] (print_circular_bug.constprop.20) from [<c017fd30>] (__lock_acquire+0xf00/0x172c) > [ 43.950197] [<c017fd30>] (__lock_acquire) from [<c0180ff8>] (lock_acquire+0x228/0x298) > [ 43.969314] [<c0180ff8>] (lock_acquire) from [<c0909a40>] (__mutex_lock+0x70/0x9b4) > [ 43.988308] [<c0909a40>] (__mutex_lock) from [<c090a3b0>] (mutex_lock_nested+0x2c/0x34) > [ 44.007837] [<c090a3b0>] (mutex_lock_nested) from [<bf07b028>] (bcm_recv+0xa4/0x10c [hci_uart]) > [ 44.028328] [<bf07b028>] (bcm_recv [hci_uart]) from [<bf079bf8>] (hci_uart_receive_buf+0x68/0x84 [hci_uart]) > [ 44.050162] [<bf079bf8>] (hci_uart_receive_buf [hci_uart]) from [<c04cf928>] (ttyport_receive_buf+0x6c/0xe4) > [ 44.072188] [<c04cf928>] (ttyport_receive_buf) from [<c04ad4d4>] (flush_to_ldisc+0xa0/0xc0) > [ 44.092841] [<c04ad4d4>] (flush_to_ldisc) from [<c013fd24>] (process_one_work+0x3c8/0x76c) > [ 44.113440] [<c013fd24>] (process_one_work) from [<c01414d0>] (worker_thread+0x2b0/0x43c) > [ 44.134095] [<c01414d0>] (worker_thread) from [<c0146fa4>] (kthread+0x158/0x174) > [ 44.153985] [<c0146fa4>] (kthread) from [<c01010b4>] (ret_from_fork+0x14/0x20) > [ 44.173718] Exception stack(0xd8fcdfb0 to 0xd8fcdff8) > [ 44.191211] dfa0: 00000000 00000000 00000000 00000000 > [ 44.212185] dfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 > [ 44.233216] dfe0: 00000000 00000000 00000000 00000000 00000013 00000000 > > _______________________________________________ > linux-rpi-kernel mailing list > linux-rpi-kernel@xxxxxxxxxxxxxxxxxxx > http://lists.infradead.org/mailman/listinfo/linux-rpi-kernel -- To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
