rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P3063/1:b..l P9589/1:b..l
(detected by 1, t=10502 jiffies, g=33305, q=67)
task:udevd state:R running task stack:25728 pid: 9589 ppid: 3562 flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11bb/0x4390 kernel/sched/core.c:6395
preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6571
preempt_schedule+0xa7/0xb0 kernel/sched/core.c:6596
preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
_raw_spin_unlock_irq+0x3c/0x40 kernel/locking/spinlock.c:202
spin_unlock_irq include/linux/spinlock.h:413 [inline]
loop_queue_work drivers/block/loop.c:1069 [inline]
loop_queue_rq+0x9e0/0xac0 drivers/block/loop.c:2202
__blk_mq_issue_directly block/blk-mq.c:2014 [inline]
__blk_mq_try_issue_directly+0x497/0x810 block/blk-mq.c:2070
blk_mq_request_issue_directly block/blk-mq.c:2118 [inline]
blk_mq_try_issue_list_directly+0x1a1/0x530 block/blk-mq.c:2136
blk_mq_sched_insert_requests+0x2d6/0x5c0 block/blk-mq-sched.c:512
blk_mq_flush_plug_list+0x57f/0x660 block/blk-mq.c:1971
blk_flush_plug_list+0x3ec/0x430 block/blk-core.c:1734
blk_finish_plug+0x59/0x80 block/blk-core.c:1751
read_pages+0x4c2/0x920 mm/readahead.c:150
page_cache_ra_unbounded+0x830/0x930 mm/readahead.c:239
do_page_cache_ra mm/readahead.c:269 [inline]
force_page_cache_ra+0x3e5/0x440 mm/readahead.c:301
page_cache_sync_readahead include/linux/pagemap.h:833 [inline]
filemap_get_pages mm/filemap.c:2551 [inline]
filemap_read+0x589/0x2480 mm/filemap.c:2634
blkdev_read_iter+0x11d/0x150 block/fops.c:563
call_read_iter include/linux/fs.h:2166 [inline]
new_sync_read fs/read_write.c:404 [inline]
vfs_read+0x725/0xcf0 fs/read_write.c:485
ksys_read+0x14d/0x250 fs/read_write.c:623
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f7be01cf407
RSP: 002b:00007ffdda406e70 EFLAGS: 00000202 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f7be00e1880 RCX: 00007f7be01cf407
RDX: 0000000000000200 RSI: 00007f7bdf790000 RDI: 0000000000000009
RBP: 000055704477f050 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 00000000003f8200 R14: 00005570447974b8 R15: 00007f7be092539c
task:kworker/u4:5 state:R running task stack:22696 pid: 3063 ppid: 2 flags:0x00004000
Workqueue: bat_events batadv_nc_worker
Call Trace:
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11bb/0x4390 kernel/sched/core.c:6395
preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6799
irqentry_exit+0x63/0x70 kernel/entry/common.c:432
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:lock_acquire+0x1f2/0x3f0 kernel/locking/lockdep.c:5627
Code: 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 0f 85 f6 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 66 43 c7 44 3d 09 00 00 43 c6 44 3d 0b
RSP: 0000:ffffc9000c75faa0 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: ec236470bce34800
RDX: 0000000000000000 RSI: ffffffff8a0b28c0 RDI: ffffffff8a59a240
RBP: ffffc9000c75fbc0 R08: dffffc0000000000 R09: fffffbfff1ff7619
R10: fffffbfff1ff7619 R11: 1ffffffff1ff7618 R12: ffffffff8c11c460
R13: 1ffff920018ebf60 R14: 0000000000000246 R15: dffffc0000000000
rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:312
rcu_read_lock include/linux/rcupdate.h:739 [inline]
batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:412 [inline]
batadv_nc_worker+0xc9/0x5c0 net/batman-adv/network-coding.c:723
process_one_work+0x863/0x1000 kernel/workqueue.c:2310
worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
rcu: rcu_preempt kthread starved for 10553 jiffies! g33305 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
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:27808 pid: 15 ppid: 2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11bb/0x4390 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
schedule_timeout+0x15c/0x280 kernel/time/timer.c:1914
rcu_gp_fqs_loop+0x29e/0x11b0 kernel/rcu/tree.c:1972
rcu_gp_kthread+0x98/0x350 kernel/rcu/tree.c:2145
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
rcu: Stack dump where RCU GP kthread last ran:
NMI backtrace for cpu 1
CPU: 1 PID: 9992 Comm: syz.2.1659 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
rcu_check_gp_kthread_starvation+0x1cd/0x250 kernel/rcu/tree_stall.h:487
print_other_cpu_stall+0x10c8/0x1220 kernel/rcu/tree_stall.h:592
check_cpu_stall kernel/rcu/tree_stall.h:745 [inline]
rcu_pending kernel/rcu/tree.c:3936 [inline]
rcu_sched_clock_irq+0x831/0x1110 kernel/rcu/tree.c:2619
update_process_times+0x193/0x200 kernel/time/timer.c:1818
tick_sched_handle kernel/time/tick-sched.c:254 [inline]
tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473
__run_hrtimer kernel/time/hrtimer.c:1690 [inline]
__hrtimer_run_queues+0x4fe/0xc40 kernel/time/hrtimer.c:1754
hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1816
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
__sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202
Code: f6 ff 0f 1f 00 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 8e 1d aa f7 48 89 df e8 56 f2 aa f7 e8 d1 8c cb f7 fb bf 01 00 00 00 a6 15 9f f7 65 8b 05 a7 13 50 76 85 c0 74 02 5b c3 e8 54 1e 4e
RSP: 0018:ffffc90003d2fbc0 EFLAGS: 00000282
RAX: 5160eb9733f59e00 RBX: ffff888077e340c0 RCX: 5160eb9733f59e00
RDX: dffffc0000000000 RSI: ffffffff8a0b1620 RDI: 0000000000000001
RBP: 0000000000000000 R08: dffffc0000000000 R09: ffffed100efc6819
R10: ffffed100efc6819 R11: 1ffff1100efc6818 R12: ffff888077e340c0
R13: 0000000000000021 R14: dffffc0000000000 R15: 000000001c000004
spin_unlock_irq include/linux/spinlock.h:413 [inline]
get_signal+0x11d6/0x12c0 kernel/signal.c:2903
arch_do_signal_or_restart+0xc1/0x1300 arch/x86/kernel/signal.c:867
handle_signal_work kernel/entry/common.c:154 [inline]
exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178
exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214
__syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fbf55e6fbe7
Code: ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 <0f> 05 48 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89
RSP: 002b:00007fbf540d70e8 EFLAGS: 00000246
RAX: 00000000000000ca RBX: 00007fbf560a6fa8 RCX: 00007fbf55e6fbe9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fbf560a6fa8
RBP: 00007fbf560a6fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fbf560a7038 R14: 00007ffecfeb75c0 R15: 00007ffecfeb76a8