=============================
WARNING: suspicious RCU usage
5.1.0-rc3-319004-g43151d6 #6 Not tainted
-----------------------------
include/linux/rcupdate.h:267 Illegal context switch in RCU read-side critical section!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 1
4 locks held by kworker/u4:4/5359:
 #0: 0000000042c1c4fb ((wq_completion)bat_events){+.+.}, at: __write_once_size include/linux/compiler.h:220 [inline]
 #0: 0000000042c1c4fb ((wq_completion)bat_events){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: 0000000042c1c4fb ((wq_completion)bat_events){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline]
 #0: 0000000042c1c4fb ((wq_completion)bat_events){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline]
 #0: 0000000042c1c4fb ((wq_completion)bat_events){+.+.}, at: set_work_data kernel/workqueue.c:619 [inline]
 #0: 0000000042c1c4fb ((wq_completion)bat_events){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline]
 #0: 0000000042c1c4fb ((wq_completion)bat_events){+.+.}, at: process_one_work+0x81f/0x1580 kernel/workqueue.c:2240
 #1: 000000003fb783e3 ((work_completion)(&(&bat_priv->nc.work)->work)){+.+.}, at: process_one_work+0x853/0x1580 kernel/workqueue.c:2244
 #2: 00000000bec45dfd (rcu_read_lock){....}, at: batadv_nc_process_nc_paths.part.0+0xb6/0x3d0 net/batman-adv/network-coding.c:695
 #3: 000000000e38cd2f ((&toneport->timer)){+.-.}, at: lockdep_copy_map include/linux/lockdep.h:170 [inline]
 #3: 000000000e38cd2f ((&toneport->timer)){+.-.}, at: call_timer_fn+0xce/0x5f0 kernel/time/timer.c:1315

stack backtrace:
CPU: 1 PID: 5359 Comm: kworker/u4:4 Not tainted 5.1.0-rc3-319004-g43151d6 #6
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: bat_events batadv_nc_worker
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0xe8/0x16e lib/dump_stack.c:113
 rcu_preempt_sleep_check include/linux/rcupdate.h:267 [inline]
 rcu_preempt_sleep_check include/linux/rcupdate.h:265 [inline]
 ___might_sleep+0x1b6/0x280 kernel/sched/core.c:6155
 __mutex_lock_common kernel/locking/mutex.c:908 [inline]
 __mutex_lock+0xcd/0x12b0 kernel/locking/mutex.c:1072
 line6_pcm_acquire+0x35/0x210 sound/usb/line6/pcm.c:311
 call_timer_fn+0x161/0x5f0 kernel/time/timer.c:1325
 expire_timers kernel/time/timer.c:1362 [inline]
 __run_timers kernel/time/timer.c:1681 [inline]
 __run_timers kernel/time/timer.c:1649 [inline]
 run_timer_softirq+0x58b/0x1400 kernel/time/timer.c:1694
 __do_softirq+0x22a/0x8cd kernel/softirq.c:293
 invoke_softirq kernel/softirq.c:374 [inline]
 irq_exit+0x187/0x1b0 kernel/softirq.c:414
 exiting_irq arch/x86/include/asm/apic.h:536 [inline]
 smp_apic_timer_interrupt+0xfe/0x4a0 arch/x86/kernel/apic/apic.c:1062
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807
 </IRQ>
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:767 [inline]
RIP: 0010:lock_acquire+0x15c/0x2f0 kernel/locking/lockdep.c:4214
Code: 0f b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 7e 01 00 00 c7 83 3c 08 00 00 00 00 00 00 48 8b 7c 24 08 57 9d <0f> 1f 44 00 00 48 83 c4 20 5b 5d 41 5c 41 5d 41 5e 41 5f c3 65 8b
RSP: 0018:ffff8880704dfc30 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000007 RBX: ffff8880946d4980 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffff8880946d5210 RDI: 0000000000000246
RBP: ffffffff917d62e0 R08: 00000000a9a778ff R09: 0000000000000028
R10: ffff8880946d5210 R11: ffff8880946d4980 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000002 R15: 0000000000000064
 rcu_lock_acquire include/linux/rcupdate.h:210 [inline]
 rcu_read_lock include/linux/rcupdate.h:595 [inline]
 batadv_nc_process_nc_paths.part.0+0xf3/0x3d0 net/batman-adv/network-coding.c:698
 batadv_nc_process_nc_paths net/batman-adv/network-coding.c:690 [inline]
 batadv_nc_worker+0x553/0x770 net/batman-adv/network-coding.c:739
 process_one_work+0x90f/0x1580 kernel/workqueue.c:2269
 worker_thread+0x9b/0xe20 kernel/workqueue.c:2415
 kthread+0x313/0x420 kernel/kthread.c:253
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352
BUG: sleeping function called from invalid context at kernel/locking/mutex.c:908
in_atomic(): 1, irqs_disabled(): 0, pid: 5359, name: kworker/u4:4
4 locks held by kworker/u4:4/5359:
 #0: 0000000042c1c4fb ((wq_completion)bat_events){+.+.}, at: __write_once_size include/linux/compiler.h:220 [inline]
 #0: 0000000042c1c4fb ((wq_completion)bat_events){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: 0000000042c1c4fb ((wq_completion)bat_events){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline]
 #0: 0000000042c1c4fb ((wq_completion)bat_events){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline]
 #0: 0000000042c1c4fb ((wq_completion)bat_events){+.+.}, at: set_work_data kernel/workqueue.c:619 [inline]
 #0: 0000000042c1c4fb ((wq_completion)bat_events){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline]
 #0: 0000000042c1c4fb ((wq_completion)bat_events){+.+.}, at: process_one_work+0x81f/0x1580 kernel/workqueue.c:2240
 #1: 000000003fb783e3 ((work_completion)(&(&bat_priv->nc.work)->work)){+.+.}, at: process_one_work+0x853/0x1580 kernel/workqueue.c:2244
 #2: 00000000bec45dfd (rcu_read_lock){....}, at: batadv_nc_process_nc_paths.part.0+0xb6/0x3d0 net/batman-adv/network-coding.c:695
 #3: 000000000e38cd2f ((&toneport->timer)){+.-.}, at: lockdep_copy_map include/linux/lockdep.h:170 [inline]
 #3: 000000000e38cd2f ((&toneport->timer)){+.-.}, at: call_timer_fn+0xce/0x5f0 kernel/time/timer.c:1315
CPU: 1 PID: 5359 Comm: kworker/u4:4 Not tainted 5.1.0-rc3-319004-g43151d6 #6
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: bat_events batadv_nc_worker
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0xe8/0x16e lib/dump_stack.c:113
 ___might_sleep.cold+0x11c/0x136 kernel/sched/core.c:6190
 __mutex_lock_common kernel/locking/mutex.c:908 [inline]
 __mutex_lock+0xcd/0x12b0 kernel/locking/mutex.c:1072
 line6_pcm_acquire+0x35/0x210 sound/usb/line6/pcm.c:311
 call_timer_fn+0x161/0x5f0 kernel/time/timer.c:1325
 expire_timers kernel/time/timer.c:1362 [inline]
 __run_timers kernel/time/timer.c:1681 [inline]
 __run_timers kernel/time/timer.c:1649 [inline]
 run_timer_softirq+0x58b/0x1400 kernel/time/timer.c:1694
 __do_softirq+0x22a/0x8cd kernel/softirq.c:293
 invoke_softirq kernel/softirq.c:374 [inline]
 irq_exit+0x187/0x1b0 kernel/softirq.c:414
 exiting_irq arch/x86/include/asm/apic.h:536 [inline]
 smp_apic_timer_interrupt+0xfe/0x4a0 arch/x86/kernel/apic/apic.c:1062
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807
 </IRQ>
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:767 [inline]
RIP: 0010:lock_acquire+0x15c/0x2f0 kernel/locking/lockdep.c:4214
Code: 0f b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 7e 01 00 00 c7 83 3c 08 00 00 00 00 00 00 48 8b 7c 24 08 57 9d <0f> 1f 44 00 00 48 83 c4 20 5b 5d 41 5c 41 5d 41 5e 41 5f c3 65 8b
RSP: 0018:ffff8880704dfc30 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000007 RBX: ffff8880946d4980 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffff8880946d5210 RDI: 0000000000000246
RBP: ffffffff917d62e0 R08: 00000000a9a778ff R09: 0000000000000028
R10: ffff8880946d5210 R11: ffff8880946d4980 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000002 R15: 0000000000000064
 rcu_lock_acquire include/linux/rcupdate.h:210 [inline]
 rcu_read_lock include/linux/rcupdate.h:595 [inline]
 batadv_nc_process_nc_paths.part.0+0xf3/0x3d0 net/batman-adv/network-coding.c:698
 batadv_nc_process_nc_paths net/batman-adv/network-coding.c:690 [inline]
 batadv_nc_worker+0x553/0x770 net/batman-adv/network-coding.c:739
 process_one_work+0x90f/0x1580 kernel/workqueue.c:2269
 worker_thread+0x9b/0xe20 kernel/workqueue.c:2415
 kthread+0x313/0x420 kernel/kthread.c:253
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352
==================================================================
BUG: KASAN: null-ptr-deref in memset include/linux/string.h:337 [inline]
BUG: KASAN: null-ptr-deref in submit_audio_out_urb+0x91e/0x1780 sound/usb/line6/playback.c:246
Write of size 20 at addr 0000000000000010 by task kworker/u4:4/5359

CPU: 1 PID: 5359 Comm: kworker/u4:4 Tainted: G        W         5.1.0-rc3-319004-g43151d6 #6
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: bat_events batadv_nc_worker
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0xe8/0x16e lib/dump_stack.c:113
 kasan_report.cold+0x5/0x3c mm/kasan/report.c:321
 memset+0x20/0x40 mm/kasan/common.c:115
 memset include/linux/string.h:337 [inline]
 submit_audio_out_urb+0x91e/0x1780 sound/usb/line6/playback.c:246
 line6_submit_audio_out_all_urbs+0xce/0x120 sound/usb/line6/playback.c:295
 line6_stream_start+0x15b/0x1f0 sound/usb/line6/pcm.c:199
 line6_pcm_acquire+0x139/0x210 sound/usb/line6/pcm.c:322
 call_timer_fn+0x161/0x5f0 kernel/time/timer.c:1325
 expire_timers kernel/time/timer.c:1362 [inline]
 __run_timers kernel/time/timer.c:1681 [inline]
 __run_timers kernel/time/timer.c:1649 [inline]
 run_timer_softirq+0x58b/0x1400 kernel/time/timer.c:1694
 __do_softirq+0x22a/0x8cd kernel/softirq.c:293
 invoke_softirq kernel/softirq.c:374 [inline]
 irq_exit+0x187/0x1b0 kernel/softirq.c:414
 exiting_irq arch/x86/include/asm/apic.h:536 [inline]
 smp_apic_timer_interrupt+0xfe/0x4a0 arch/x86/kernel/apic/apic.c:1062
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807
 </IRQ>
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:767 [inline]
RIP: 0010:lock_acquire+0x15c/0x2f0 kernel/locking/lockdep.c:4214
Code: 0f b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 7e 01 00 00 c7 83 3c 08 00 00 00 00 00 00 48 8b 7c 24 08 57 9d <0f> 1f 44 00 00 48 83 c4 20 5b 5d 41 5c 41 5d 41 5e 41 5f c3 65 8b
RSP: 0018:ffff8880704dfc30 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000007 RBX: ffff8880946d4980 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffff8880946d5210 RDI: 0000000000000246
RBP: ffffffff917d62e0 R08: 00000000a9a778ff R09: 0000000000000028
R10: ffff8880946d5210 R11: ffff8880946d4980 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000002 R15: 0000000000000064
 rcu_lock_acquire include/linux/rcupdate.h:210 [inline]
 rcu_read_lock include/linux/rcupdate.h:595 [inline]
 batadv_nc_process_nc_paths.part.0+0xf3/0x3d0 net/batman-adv/network-coding.c:698
 batadv_nc_process_nc_paths net/batman-adv/network-coding.c:690 [inline]
 batadv_nc_worker+0x553/0x770 net/batman-adv/network-coding.c:739
 process_one_work+0x90f/0x1580 kernel/workqueue.c:2269
 worker_thread+0x9b/0xe20 kernel/workqueue.c:2415
 kthread+0x313/0x420 kernel/kthread.c:253
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352
==================================================================