rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 1-...!: (1 GPs behind) idle=542c/1/0x4000000000000000 softirq=140559/140562 fqs=10
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P23510/3:b..l P23511
rcu: (detected by 0, t=10506 jiffies, g=148741, q=172 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 23511 Comm: syz-executor Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:check_preemption_disabled+0x23/0xe0 lib/smp_processor_id.c:54
Code: 90 90 90 90 90 90 90 41 54 55 53 48 83 ec 08 65 8b 1d f5 25 7b 08 65 f7 05 e6 25 7b 08 ff ff ff 7f 74 0f 48 83 c4 08 89 d8 5b <5d> 41 5c e9 c5 26 03 00 9c 58 f6 c4 02 74 ea 65 4c 8b 25 ae 25 7b
RSP: 0018:ffffc90000a08ce0 EFLAGS: 00000086
RAX: 0000000000000001 RBX: ffffffff9b477088 RCX: 1ffff1100fb8ffde
RDX: ffffffff8bb2f940 RSI: ffffffff8c1cef00 RDI: ffffffff8c1cef40
RBP: ffffffff85064b01 R08: 0000000000000001 R09: fffff5200014119c
R10: 0000000000000002 R11: 0000000000000001 R12: 0000000000000002
R13: ffff88804127b300 R14: dffffc0000000000 R15: 1ffff920001411b2
FS: 00005555780e8500(0000) GS:ffff888124432000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c2bb89b CR3: 00000000312cc000 CR4: 00000000003526f0
Call Trace:
rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline]
rcu_is_watching+0x12/0xc0 kernel/rcu/tree.c:752
trace_lock_release include/trace/events/lock.h:68 [inline]
lock_release+0x24d/0x310 kernel/locking/lockdep.c:5879
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:176 [inline]
_raw_spin_unlock_irqrestore+0x1a/0x80 kernel/locking/spinlock.c:198
debug_object_activate+0x331/0x490 lib/debugobjects.c:891
debug_hrtimer_activate kernel/time/hrtimer.c:485 [inline]
debug_activate kernel/time/hrtimer.c:528 [inline]
enqueue_hrtimer+0x75/0x2f0 kernel/time/hrtimer.c:1109
__run_hrtimer kernel/time/hrtimer.c:2048 [inline]
__hrtimer_run_queues+0x6ed/0x9c0 kernel/time/hrtimer.c:2096
hrtimer_interrupt+0x3e5/0x940 kernel/time/hrtimer.c:2215
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline]
__sysvec_apic_timer_interrupt+0x109/0x470 arch/x86/kernel/apic/apic.c:1068
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1062
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:finish_task_switch.isra.0+0x2cd/0x1010 kernel/sched/core.c:5361
Code: 2f 0a 00 00 41 c7 87 20 0e 00 00 00 00 00 00 e9 0f 04 00 00 49 8d 7f 48 e8 c0 84 c1 09 e8 6b a2 3c 00 fb 48 8d bb f8 16 00 00 <48> b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 0f b6 04 02 84
RSP: 0018:ffffc900085bf788 EFLAGS: 00000246
RAX: 0000000000000001 RBX: ffff88802ccd2540 RCX: ffffffff8211b23f
RDX: 0000000000000000 RSI: ffffffff8c1cef00 RDI: ffff88802ccd3c38
RBP: ffffc900085bf7e0 R08: 0000000000000000 R09: fffffbfff21b3292
R10: 0000000000000000 R11: ffffffff81d50f9c R12: ffff88801eaa4a80
R13: 0000000000000001 R14: ffffffff90d9c864 R15: ffff8880b853b340
context_switch kernel/sched/core.c:5507 [inline]
__schedule+0x1264/0x6730 kernel/sched/core.c:7228
preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7552
irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:468 [inline]
irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline]
irqentry_exit+0x205/0xa00 kernel/entry/common.c:167
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:unwind_next_frame+0xf8/0x2090 arch/x86/kernel/unwind_orc.c:498
Code: 8e 2d 00 e8 4a 2e dc 09 5a 85 c0 0f 85 16 06 00 00 48 b8 00 00 00 00 00 fc ff df 4d 8d 65 50 4c 89 e2 48 c1 ea 03 80 3c 02 00 <0f> 85 c9 18 00 00 4d 8b 75 50 4d 85 f6 74 36 49 8d be 88 00 00 00
RSP: 0018:ffffc900085bfa68 EFLAGS: 00000246
RAX: dffffc0000000000 RBX: 0000000000000001 RCX: 0000000000000002
RDX: 1ffff920010b7f65 RSI: 0000000000000000 RDI: ffffffff8e1e7928
RBP: ffffc900085bfb20 R08: 0000000000000000 R09: 0000000000000000
R10: ffffc900085bfad8 R11: 0000000000016dd7 R12: ffffc900085bfb28
R13: ffffc900085bfad8 R14: 0000000000000000 R15: ffff88802ccd2540
arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
kasan_save_track+0x14/0x30 mm/kasan/common.c:78
kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:253 [inline]
__kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:2700 [inline]
slab_free mm/slub.c:6310 [inline]
kmem_cache_free+0x127/0x6b0 mm/slub.c:6437
free_filename fs/namei.c:152 [inline]
putname+0xb1/0x110 fs/namei.c:311
class_filename_destructor include/linux/fs.h:2564 [inline]
__do_sys_symlinkat fs/namei.c:5700 [inline]
__se_sys_symlinkat fs/namei.c:5696 [inline]
__x64_sys_symlinkat+0xa6/0xe0 fs/namei.c:5696
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb549d9bf17
Code: 44 00 00 48 89 f2 31 c9 48 89 fe bf 9c ff ff ff e9 8e f5 ff ff 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 b8 0a 01 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe4d431698 EFLAGS: 00000202 ORIG_RAX: 000000000000010a
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fb549d9bf17
RDX: 00007fb549e33d31 RSI: 00000000ffffff9c RDI: 00007ffe4d431730
RBP: 00007ffe4d4316dc R08: 0000000000000001 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000202 R12: 00000000000003c9
R13: 00000000000927c0 R14: 000000000010e630 R15: 00007ffe4d431730
task:syz-executor state:R running task stack:28728 pid:23511 tgid:23511 ppid:5607 task_flags:0x400040 flags:0x00080010
Call Trace:
task:syz.3.4986 state:R running task stack:27360 pid:23510 tgid:23510 ppid:5618 task_flags:0x400040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5504 [inline]
__schedule+0x125c/0x6730 kernel/sched/core.c:7228
preempt_schedule_common+0x42/0xc0 kernel/sched/core.c:7409
preempt_schedule_thunk+0x16/0x40 arch/x86/entry/thunk.S:12
__raw_spin_unlock include/linux/spinlock_api_smp.h:169 [inline]
_raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:190
spin_unlock include/linux/spinlock.h:390 [inline]
filemap_map_pages+0x14ad/0x20a0 mm/filemap.c:3953
do_fault_around mm/memory.c:5867 [inline]
do_read_fault mm/memory.c:5900 [inline]
do_fault+0x985/0x1750 mm/memory.c:6043
do_pte_missing mm/memory.c:4566 [inline]
handle_pte_fault mm/memory.c:6427 [inline]
__handle_mm_fault+0x187d/0x2a00 mm/memory.c:6565
handle_mm_fault+0x37b/0xa30 mm/memory.c:6734
do_user_addr_fault+0x5a3/0x12f0 arch/x86/mm/fault.c:1343
handle_page_fault arch/x86/mm/fault.c:1483 [inline]
exc_page_fault+0x6f/0xd0 arch/x86/mm/fault.c:1536
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:595
RIP: 0033:0x7f8c84271756
RSP: 002b:00007ffc7db16690 EFLAGS: 00010202
RAX: 000000110c2b8000 RBX: ffffffff82961ed1 RCX: 0000000000000002
RDX: 0000000000001ed1 RSI: 000000000000187b RDI: 0000000000000004
RBP: 0000000000000000 R08: 00007f8c84600000 R09: 00007f8c84602000
R10: 0000000082961ed5 R11: 0000000000000000 R12: 00007f8c84616038
R13: 0000000000000003 R14: ffffffff829616dd R15: 00007f8c85145720
rcu: rcu_preempt kthread starved for 10455 jiffies! g148741 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:28576 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5504 [inline]
__schedule+0x125c/0x6730 kernel/sched/core.c:7228
__schedule_loop kernel/sched/core.c:7307 [inline]
schedule+0xdd/0x390 kernel/sched/core.c:7322
schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2123
rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2325
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 1220 Comm: kworker/0:2 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Workqueue: events fqdir_free_fn
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_single+0x204/0x710 kernel/smp.c:702
Code: bc 24 ce 00 00 00 48 89 84 24 d8 00 00 00 e8 a3 f9 ff ff 89 44 24 2c 0f 1f 44 00 00 e8 c5 72 0c 00 eb 07 e8 be 72 0c 00 f3 90 <8b> 9c 24 c8 00 00 00 31 ff 83 e3 01 89 de e8 59 6d 0c 00 85 db 75
RSP: 0018:ffffc90005627a40 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff81fcfdb7
RDX: ffff88802a16ca80 RSI: ffffffff81fcfda2 RDI: ffff88802a16ca80
RBP: ffffc90005627b88 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: ffff8880b853c3c0 R15: ffff8880b853c508
FS: 0000000000000000(0000) GS:ffff888124332000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000003a9030 CR3: 0000000020f50000 CR4: 00000000003526f0
Call Trace:
rcu_barrier kernel/rcu/tree.c:3909 [inline]
rcu_barrier+0x2a4/0x6d0 kernel/rcu/tree.c:3846
fqdir_free_fn+0x32/0x140 net/ipv4/inet_fragment.c:164
process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
process_scheduled_works kernel/workqueue.c:3405 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245