INFO: rcu detected stall in batadv_nc

INFO: rcu detected stall in batadv_nc_worker (3)
Status: upstream: reported on 2020/10/01 10:35
Reported-by: syzbot+69904c3b4a09e8fa2e1b@syzkaller.appspotmail.com
First crash: 250d, last: 15d

similar bugs (2):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	INFO: rcu detected stall in batadv_nc_worker				7	408d	409d	0/17	closed as invalid on 2019/12/04 14:04
upstream	INFO: rcu detected stall in batadv_nc_worker (2)				4	373d	373d	0/17	closed as invalid on 2020/01/09 08:13

Sample crash report:

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (0 ticks this GP) idle=00a/1/0x4000000000000000 softirq=16819/16819 fqs=0 
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1):
	(detected by 0, t=10502 jiffies, g=22677, q=157)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 11723 Comm: syz-executor.3 Not tainted 5.11.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:queued_write_lock_slowpath+0x131/0x270 kernel/locking/qrwlock.c:77
Code: 00 00 00 00 fc ff df 49 01 c7 41 83 c6 03 41 0f b6 07 41 38 c6 7c 08 84 c0 0f 85 fe 00 00 00 8b 03 3d 00 01 00 00 74 19 f3 90 <41> 0f b6 07 41 38 c6 7c ec 84 c0 74 e8 48 89 df e8 2a c1 5b 00 eb
RSP: 0018:ffffc90001f5fa60 EFLAGS: 00000006
RAX: 0000000000000300 RBX: ffffffff8b00a080 RCX: ffffffff815946ba
RDX: fffffbfff1601411 RSI: 0000000000000004 RDI: ffffffff8b00a080
RBP: 00000000000000ff R08: 0000000000000001 R09: ffffffff8b00a083
R10: fffffbfff1601410 R11: 0000000000000000 R12: 1ffff920003ebf4d
R13: ffffffff8b00a084 R14: 0000000000000003 R15: fffffbfff1601410
FS:  0000000000000000(0000) GS:ffff8880b9f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000557fcc3f1c30 CR3: 000000002da21000 CR4: 0000000000350ee0
Call Trace:
 queued_write_lock include/asm-generic/qrwlock.h:95 [inline]
 do_raw_write_lock+0x1ce/0x280 kernel/locking/spinlock_debug.c:207
 exit_notify kernel/exit.c:666 [inline]
 do_exit+0xbd7/0x29e0 kernel/exit.c:843
 do_group_exit+0x125/0x310 kernel/exit.c:920
 get_signal+0x3ec/0x2010 kernel/signal.c:2770
 arch_do_signal_or_restart+0x2a8/0x1eb0 arch/x86/kernel/signal.c:811
 handle_signal_work kernel/entry/common.c:147 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:171 [inline]
 exit_to_user_mode_prepare+0x148/0x250 kernel/entry/common.c:201
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:302
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45e219
Code: Unable to access opcode bytes at RIP 0x45e1ef.
RSP: 002b:00007fe1cfbeec68 EFLAGS: 00000246 ORIG_RAX: 000000000000010e
RAX: fffffffffffffdfe RBX: 0000000000000006 RCX: 000000000045e219
RDX: 0000000000000000 RSI: 00000000200001c0 RDI: 0000000000000040
RBP: 000000000119bfd8 R08: 0000000020000200 R09: 0000000000000000
R10: 0000000020000140 R11: 0000000000000246 R12: 000000000119bf8c
R13: 00007ffc0012e4bf R14: 00007fe1cfbef9c0 R15: 000000000119bf8c
task:kworker/u4:3    state:R  running task     stack:24736 pid:  124 ppid:     2 flags:0x00004000
Workqueue: bat_events batadv_nc_worker
Call Trace:
 context_switch kernel/sched/core.c:4313 [inline]
 __schedule+0x90c/0x21a0 kernel/sched/core.c:5064
 preempt_schedule_irq+0x4e/0x90 kernel/sched/core.c:5326
 irqentry_exit_cond_resched kernel/entry/common.c:393 [inline]
 irqentry_exit_cond_resched kernel/entry/common.c:385 [inline]
 irqentry_exit+0x7a/0xa0 kernel/entry/common.c:423
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:628
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/irqflags.h:85 [inline]
RIP: 0010:lock_acquire kernel/locking/lockdep.c:5440 [inline]
RIP: 0010:lock_acquire+0x2c7/0x740 kernel/locking/lockdep.c:5402
Code: 48 c7 c7 80 a1 4b 89 48 83 c4 20 e8 53 14 93 07 b8 ff ff ff ff 65 0f c1 05 76 72 a9 7e 83 f8 01 0f 85 36 03 00 00 ff 34 24 9d <e9> 3a fe ff ff 65 ff 05 dd 60 a9 7e 48 8b 05 b6 fd 82 0b e8 71 09
RSP: 0018:ffffc90000f6fb30 EFLAGS: 00000246
RAX: 0000000000000001 RBX: 1ffff920001edf68 RCX: 0000000000000001
RDX: 1ffff1100220b4a8 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff8ebda7a7
R10: fffffbfff1d7b4f4 R11: 0000000000000000 R12: 0000000000000002
R13: ffffffff8b363860 R14: 0000000000000000 R15: 0000000000000000
 rcu_lock_acquire include/linux/rcupdate.h:253 [inline]
 rcu_read_lock include/linux/rcupdate.h:642 [inline]
 batadv_nc_process_nc_paths.part.0+0xec/0x3b0 net/batman-adv/network-coding.c:683
 batadv_nc_process_nc_paths net/batman-adv/network-coding.c:675 [inline]
 batadv_nc_worker+0xaf2/0xe50 net/batman-adv/network-coding.c:724
 process_one_work+0x98d/0x15f0 kernel/workqueue.c:2275
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421
 kthread+0x3b1/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
rcu: rcu_preempt kthread starved for 10502 jiffies! g22677 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt     state:R  running task     stack:28880 pid:   11 ppid:     2 flags:0x00004000
Call Trace:
 context_switch kernel/sched/core.c:4313 [inline]
 __schedule+0x90c/0x21a0 kernel/sched/core.c:5064
 schedule+0xcf/0x270 kernel/sched/core.c:5143
 schedule_timeout+0x148/0x250 kernel/time/timer.c:1878
 rcu_gp_fqs_loop kernel/rcu/tree.c:1940 [inline]
 rcu_gp_kthread+0xbbe/0x1d70 kernel/rcu/tree.c:2113
 kthread+0x3b1/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

Crashes (12):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	VM info	Maintainers
ci-upstream-kasan-gce-root	2020/12/31 16:10	upstream	f6e1ea19	79264ae3	.config	log	report	info	akpm@linux-foundation.org, ast@kernel.org, christian@brauner.io, ebiederm@xmission.com, linux-kernel@vger.kernel.org, minchan@kernel.org, peterz@infradead.org
ci-upstream-kasan-gce-root	2020/10/09 00:16	upstream	3d006ee4	92390980	.config	log	report	info	davem@davemloft.net, jhs@mojatatu.com, jiri@resnulli.us, kuba@kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, xiyou.wangcong@gmail.com
ci-upstream-kasan-gce-smack-root	2020/08/06 00:31	upstream	fffe3ae0	0487ea6f	.config	log	report		linux-kernel@vger.kernel.org, tglx@linutronix.de
ci-upstream-kasan-gce-root	2020/07/08 03:46	upstream	7cc2a8ea	51095195	.config	log	report		davem@davemloft.net, jhs@mojatatu.com, jiri@resnulli.us, kuba@kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, xiyou.wangcong@gmail.com
ci-upstream-kasan-gce-smack-root	2020/07/07 14:37	upstream	7cc2a8ea	51095195	.config	log	report		linux-kernel@vger.kernel.org, tglx@linutronix.de
ci-upstream-kasan-gce-selinux-root	2020/05/30 22:53	upstream	ffeb595d	6f3e1c7c	.config	log	report		bp@alien8.de, hpa@zytor.com, linux-kernel@vger.kernel.org, mingo@redhat.com, peterz@infradead.org, tglx@linutronix.de, tony.luck@intel.com, x86@kernel.org
ci-upstream-kasan-gce-root	2020/05/10 07:00	upstream	1d3962ae	8742a2b9	.config	log	report		bp@alien8.de, hpa@zytor.com, linux-kernel@vger.kernel.org, mingo@redhat.com, peterz@infradead.org, tglx@linutronix.de, tony.luck@intel.com, x86@kernel.org
ci-upstream-kasan-gce-386	2020/07/13 03:50	upstream	4437dd6e	9ebcc5b1	.config	log	report		fweisbec@gmail.com, linux-kernel@vger.kernel.org, mingo@kernel.org, tglx@linutronix.de
ci-upstream-net-this-kasan-gce	2020/07/22 15:39	net	2c4dc314	128cd85f	.config	log	report		fweisbec@gmail.com, linux-kernel@vger.kernel.org, mingo@kernel.org, tglx@linutronix.de
ci-upstream-net-this-kasan-gce	2020/07/03 01:55	net	e4b9a72d	bed10395	.config	log	report		davem@davemloft.net, jhs@mojatatu.com, jiri@resnulli.us, kuba@kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, xiyou.wangcong@gmail.com
ci-upstream-net-kasan-gce	2020/09/01 04:44	net-next	c30a3c95	d5a3ae1f	.config	log	report		linux-kernel@vger.kernel.org, tglx@linutronix.de
ci-upstream-linux-next-kasan-gce-root	2020/09/02 03:53	linux-next	b36c9697	abf9ba4f	.config	log	report		linux-kernel@vger.kernel.org, tglx@linutronix.de