[v6.1] INFO: rcu detected stall in nsim_fib_event_work (3)

Hello,

syzbot found the following issue on:

HEAD commit: 344a09659766 Linux 6.1.131
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1435483f980000
kernel config: https://syzkaller.appspot.com/x/.config?x=14d5dbae75afa499
dashboard link: https://syzkaller.appspot.com/bug?extid=ebe2f7e1fa5bbdca1069
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: arm64
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=163b684c580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/8c94453bbad3/disk-344a0965.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6bf26518c790/vmlinux-344a0965.xz
kernel image: https://storage.googleapis.com/syzbot-assets/424da9a470eb/Image-344a0965.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email protected]

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4362/1:b..l
(detected by 0, t=10502 jiffies, g=6305, q=387 ncpus=2)
task:kworker/1:1 state:R running task stack:0 pid:4362 ppid:2 flags:0x00000008
Workqueue: events nsim_fib_event_work
Call trace:
__switch_to+0x308/0x598 arch/arm64/kernel/process.c:553
context_switch kernel/sched/core.c:5243 [inline]
__schedule+0xef4/0x1d44 kernel/sched/core.c:6560
preempt_schedule_irq+0x8c/0x1b8 kernel/sched/core.c:6872
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
memcmp lib/string.c:765 [inline]
bcmp+0x4c/0x1c8 lib/string.c:797
_Z6memcmpPKvU17pass_object_size0S0_U17pass_object_size0m include/linux/fortify-string.h:549 [inline]
rhashtable_compare include/linux/rhashtable.h:577 [inline]
__rhashtable_lookup include/linux/rhashtable.h:602 [inline]
rhashtable_lookup include/linux/rhashtable.h:638 [inline]
rhashtable_lookup_fast+0x3f0/0x814 include/linux/rhashtable.h:664
nsim_fib_rt_lookup drivers/net/netdevsim/fib.c:271 [inline]
nsim_fib4_rt_lookup drivers/net/netdevsim/fib.c:308 [inline]
nsim_fib4_rt_insert drivers/net/netdevsim/fib.c:430 [inline]
nsim_fib4_event drivers/net/netdevsim/fib.c:464 [inline]
nsim_fib_event drivers/net/netdevsim/fib.c:884 [inline]
nsim_fib_event_work+0x1040/0x3320 drivers/net/netdevsim/fib.c:1494
process_one_work+0x804/0x1484 kernel/workqueue.c:2292
process_scheduled_works kernel/workqueue.c:2355 [inline]
worker_thread+0xb6c/0xfec kernel/workqueue.c:2441
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 10499 jiffies! g6305 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=0 timer-softirq=17438
rcu: rcu_preempt kthread starved for 10500 jiffies! g6305 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+0x308/0x598 arch/arm64/kernel/process.c:553
context_switch kernel/sched/core.c:5243 [inline]
__schedule+0xef4/0x1d44 kernel/sched/core.c:6560
schedule+0xc4/0x170 kernel/sched/core.c:6636
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: 4515 Comm: syz.2.32 Not tainted 6.1.131-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
pc : _raw_spin_unlock_irq+0x44/0x90 kernel/locking/spinlock.c:202
lr : __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:159 [inline]
lr : _raw_spin_unlock_irq+0x3c/0x90 kernel/locking/spinlock.c:202
sp : ffff800021fc79c0
x29: ffff800021fc79c0 x28: ffff0000d69bc558 x27: ffff800021fc7d60
x26: 1ffff000043f8f54 x25: dfff800000000000 x24: 1fffe0001ad378ab
x23: 0000000000000021 x22: 0000000000000020 x21: 0000ffffb9181390
x20: ffff0000cff55340 x19: ffff0000d69bc0c0 x18: 1fffe0001a72cd94
x17: 0000000000000000 x16: ffff800008302738 x15: 0000000000000000
x14: 0000000000000001 x13: 0000000000000000 x12: 0000000000000003
x11: 0000000000ff0100 x10: 0000000000000003 x9 : 0000000000000000
x8 : 00000000000000e0 x7 : 0000000018000004 x6 : 0000ffffb9181390
x5 : ffff800021fc7d80 x4 : ffff0000d69bc578 x3 : 0000000000000000
x2 : ffff800021fc78e0 x1 : ffff80001248d5c0 x0 : ffff80019e26e000
Call trace:
arch_local_irq_enable arch/arm64/include/asm/irqflags.h:35 [inline]
__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:159 [inline]
_raw_spin_unlock_irq+0x44/0x90 kernel/locking/spinlock.c:202
spin_unlock_irq include/linux/spinlock.h:401 [inline]
get_signal+0x1258/0x1528 kernel/signal.c:2874
do_signal arch/arm64/kernel/signal.c:1076 [inline]
do_notify_resume+0x2f8/0x2cb8 arch/arm64/kernel/signal.c:1129
prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:137 [inline]
exit_to_user_mode arch/arm64/kernel/entry-common.c:142 [inline]
el0_svc+0x9c/0x168 arch/arm64/kernel/entry-common.c:638
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585


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