syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P4578/1:b..l
	(detected by 0, t=10502 jiffies, g=14773, q=75 ncpus=2)
task:kworker/u4:9    state:R  running task     stack:0     pid:4578  ppid:2      flags:0x00000008
Workqueue: bat_events batadv_nc_worker
Call trace:
 __switch_to+0x320/0x754 arch/arm64/kernel/process.c:553
 context_switch kernel/sched/core.c:5241 [inline]
 __schedule+0xef4/0x1d44 kernel/sched/core.c:6558
 preempt_schedule_irq+0x8c/0x1b8 kernel/sched/core.c:6870
 arm64_preempt_schedule_irq arch/arm64/kernel/entry-common.c:265 [inline]
 __el1_irq arch/arm64/kernel/entry-common.c:474 [inline]
 el1_interrupt+0x4c/0x68 arch/arm64/kernel/entry-common.c:486
 el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:491
 el1h_64_irq+0x64/0x68 arch/arm64/kernel/entry.S:581
 preempt_count arch/arm64/include/asm/preempt.h:13 [inline]
 check_kcov_mode kernel/kcov.c:173 [inline]
 write_comp_data kernel/kcov.c:236 [inline]
 __sanitizer_cov_trace_const_cmp4+0x14/0x98 kernel/kcov.c:304
 process_one_work+0x7ac/0x1404 kernel/workqueue.c:2292
 worker_thread+0x8e4/0xfec kernel/workqueue.c:2439
 kthread+0x250/0x2d8 kernel/kthread.c:376
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:864
rcu: rcu_preempt kthread timer wakeup didn't happen for 10274 jiffies! g14773 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=8404
rcu: rcu_preempt kthread starved for 10276 jiffies! g14773 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:0     pid:16    ppid:2      flags:0x00000008
Call trace:
 __switch_to+0x320/0x754 arch/arm64/kernel/process.c:553
 context_switch kernel/sched/core.c:5241 [inline]
 __schedule+0xef4/0x1d44 kernel/sched/core.c:6558
 schedule+0xc4/0x170 kernel/sched/core.c:6634
 schedule_timeout+0x1d8/0x344 kernel/time/timer.c:1965
 rcu_gp_fqs_loop+0x2cc/0x1538 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0xc0/0x308 kernel/rcu/tree.c:1905
 kthread+0x250/0x2d8 kernel/kthread.c:376
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:864
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 PID: 5531 Comm: syz.4.314 Not tainted 6.1.103-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
pstate: 20400005 (nzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : __sanitizer_cov_trace_cmp8+0x8/0x90 kernel/kcov.c:284
lr : __on_sig_stack include/linux/sched/signal.h:587 [inline]
lr : on_sig_stack include/linux/sched/signal.h:608 [inline]
lr : do_sigaltstack kernel/signal.c:4202 [inline]
lr : restore_altstack+0x2bc/0x518 kernel/signal.c:4258
sp : ffff80001ebd74f0
x29: ffff80001ebd75c0 x28: ffff700003d7aea8 x27: 1fffe0001a2c6123
x26: 0000000000000000 x25: 0000ffff94a63a30 x24: 0000000000000002
x23: dfff800000000000 x22: 0000000000000002 x21: 0000000000000000
x20: ffff0000d1630918 x19: ffff0000d1630000 x18: 0000000000000000
x17: 0000000000000000 x16: ffff8000121d2200 x15: 0000ffff94a62860
x14: 1ffff00002b380b0 x13: dfff800000000000 x12: 0000000000000003
x11: 0000000000ff0100 x10: 0000000000000002 x9 : ffff0000d1630000
x8 : 0000000000000000 x7 : 0000000000000000 x6 : ffff80001ebd7578
x5 : ffff80001ebd7578 x4 : 0000000000000000 x3 : 0000000000000000
x2 : 0000000000000018 x1 : 0000000000000000 x0 : 0000ffff94a63a30
Call trace:
 __sanitizer_cov_trace_cmp8+0x8/0x90 kernel/kcov.c:283
 __arm64_sys_rt_sigreturn+0x20a4/0x2658 arch/arm64/kernel/signal.c:700
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585