rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P10755/1:b..l
rcu: (detected by 1, t=10502 jiffies, g=50937, q=291 ncpus=2)
task:syz.3.916 state:R running task stack:25896 pid:10755 ppid:9092 flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x1553/0x45a0 kernel/sched/core.c:6700
preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7010
irqentry_exit+0x67/0x70 kernel/entry/common.c:438
asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:692
RIP: 0010:lockdep_enabled kernel/locking/lockdep.c:122 [inline]
RIP: 0010:lock_acquire+0x10a/0x420 kernel/locking/lockdep.c:5730
Code: 0f 85 1d 02 00 00 83 3d 1f f1 22 0d 00 0f 84 0c 01 00 00 65 8b 05 8e 68 9a 7e 85 c0 0f 85 44 01 00 00 65 4c 8b 35 56 94 9b 7e <49> 81 c6 dc 0a 00 00 4c 89 f0 48 c1 e8 03 42 0f b6 04 38 84 c0 0f
RSP: 0018:ffffc9000b757560 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 262bf8572d05a400
RDX: 0000000000000000 RSI: ffffffff8b1c81c0 RDI: ffffffff8b1c8180
RBP: ffffc9000b757678 R08: ffffffff8e8addaf R09: 1ffffffff1d15bb5
R10: dffffc0000000000 R11: fffffbfff1d15bb6 R12: 1ffff920016eaeb8
R13: ffffffff8d131fa0 R14: ffff888021530000 R15: dffffc0000000000
rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
rcu_read_lock include/linux/rcupdate.h:786 [inline]
atomic_notifier_call_chain+0x42/0x180 kernel/notifier.c:230
notify_write drivers/tty/vt/vt.c:267 [inline]
vc_con_write_normal drivers/tty/vt/vt.c:2839 [inline]
do_con_write+0x1b7b/0x6e50 drivers/tty/vt/vt.c:2909
con_write+0x24/0x40 drivers/tty/vt/vt.c:3245
process_output_block drivers/tty/n_tty.c:580 [inline]
n_tty_write+0xd34/0x11e0 drivers/tty/n_tty.c:2395
iterate_tty_write drivers/tty/tty_io.c:1017 [inline]
file_tty_write+0x54b/0x980 drivers/tty/tty_io.c:1088
call_write_iter include/linux/fs.h:2018 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x46c/0x990 fs/read_write.c:584
ksys_write+0x150/0x260 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f794539bf79
RSP: 002b:00007f79461e2028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f7945616090 RCX: 00007f794539bf79
RDX: 0000000000001006 RSI: 0000200000002080 RDI: 0000000000000006
RBP: 00007f79454327e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7945616128 R14: 00007f7945616090 R15: 00007fffcf289688
rcu: rcu_preempt kthread starved for 9657 jiffies! g50937 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:26728 pid:17 ppid:2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x1553/0x45a0 kernel/sched/core.c:6700
schedule+0xbd/0x170 kernel/sched/core.c:6774
schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168
rcu_gp_fqs_loop+0x313/0x1590 kernel/rcu/tree.c:1667
rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:1866
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
RIP: 0010:pv_native_safe_halt+0xf/0x10 arch/x86/kernel/paravirt.c:148
Code: d7 22 02 c3 cc cc cc cc cc cc cc f3 0f 1e fa 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 66 90 0f 00 2d 83 e1 43 00 fb f4 66 0f 1f 00 55 41 57 41 56 41 54 53 50 8b 2f eb 2e 41 89 de 80
RSP: 0018:ffffffff8ce07d80 EFLAGS: 000002c2
RAX: 8c7bf1b8c8011f00 RBX: ffffffff8162a490 RCX: 8c7bf1b8c8011f00
RDX: 0000000000000001 RSI: ffffffff8acac900 RDI: ffffffff8b1c81e0
RBP: ffffffff8ce07eb8 R08: ffff8880b8e36b2b R09: 1ffff110171c6d65
R10: dffffc0000000000 R11: ffffed10171c6d66 R12: 1ffffffff19d2688
R13: 1ffffffff19c0fbc R14: 0000000000000000 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7c06482818 CR3: 000000002ff58000 CR4: 00000000003506f0
Call Trace:
arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline]
default_idle+0x13/0x20 arch/x86/kernel/process.c:753
default_idle_call+0x6c/0xa0 kernel/sched/idle.c:97
cpuidle_idle_call kernel/sched/idle.c:170 [inline]
do_idle+0x1f0/0x4e0 kernel/sched/idle.c:282
cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:380
rest_init+0x2e2/0x300 init/main.c:744
arch_call_rest_init+0xe/0x10 init/main.c:841
start_kernel+0x459/0x4e0 init/main.c:1086
x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:555
x86_64_start_kernel+0x60/0x60 arch/x86/kernel/head64.c:536
secondary_startup_64_no_verify+0x179/0x17b
NMI backtrace for cpu 1
CPU: 1 PID: 10753 Comm: syz.2.918 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
RIP: 0010:hlock_class kernel/locking/lockdep.c:223 [inline]
RIP: 0010:mark_lock+0x66/0x320 kernel/locking/lockdep.c:4656
Code: b6 47 02 24 03 3c 01 bd 09 00 00 00 83 dd 00 41 bc 01 00 00 00 89 e9 41 d3 e4 4d 8d 7e 20 4c 89 f8 48 c1 e8 03 42 0f b6 04 28 <84> c0 0f 85 22 02 00 00 41 8b 07 41 89 c7 41 81 e7 ff 1f 00 00 c1
RSP: 0018:ffffc900001f0980 EFLAGS: 00000806
RAX: 0000000000000000 RBX: ffff888028bd0000 RCX: 0000000000000001
RDX: 0000000000000001 RSI: ffff888028bd0ae0 RDI: ffff888028bd0000
RBP: 0000000000000001 R08: dffffc0000000000 R09: 1ffffffff2237ea1
R10: dffffc0000000000 R11: fffffbfff2237ea2 R12: 0000000000000002
R13: dffffc0000000000 R14: ffff888028bd0ae0 R15: ffff888028bd0b00
FS: 00007ff3f145f6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055555a924a28 CR3: 000000005e6e1000 CR4: 00000000003506e0
Call Trace:
mark_usage kernel/locking/lockdep.c:4555 [inline]
__lock_acquire+0xc69/0x7d40 kernel/locking/lockdep.c:5091
lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5754
seqcount_lockdep_reader_access+0xd1/0x1d0 include/linux/seqlock.h:102
ktime_get+0x35/0x280 kernel/time/timekeeping.c:846
clockevents_program_event+0xe6/0x310 kernel/time/clockevents.c:326
hrtimer_interrupt+0x5a1/0x9c0 kernel/time/hrtimer.c:1889
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1077 [inline]
__sysvec_apic_timer_interrupt+0xfb/0x3b0 arch/x86/kernel/apic/apic.c:1094
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1088
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x29/0x50 kernel/locking/spinlock.c:202
Code: 00 f3 0f 1e fa 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 ba 9c da f6 48 89 df e8 72 71 db f6 e8 1d 7d ff f6 fb bf 01 00 00 00 92 78 ce f6 65 8b 05 63 af 75 75 85 c0 74 02 5b c3 e8 e0 96 72
RSP: 0018:ffffc9000b70fc78 EFLAGS: 00000286
RAX: 970a1fb3e203e400 RBX: ffff888065f11bc0 RCX: 970a1fb3e203e400
RDX: dffffc0000000000 RSI: ffffffff8acac900 RDI: 0000000000000001
RBP: ffff888065f12058 R08: ffffffff8e8addaf R09: 1ffffffff1d15bb5
R10: dffffc0000000000 R11: fffffbfff1d15bb6 R12: 1ffff1100cbe240b
R13: 0000000000000021 R14: dffffc0000000000 R15: 0000000000000000
spin_unlock_irq include/linux/spinlock.h:401 [inline]
get_signal+0x11f5/0x13f0 kernel/signal.c:2905
arch_do_signal_or_restart+0xc2/0x800 arch/x86/kernel/signal.c:310
exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
do_syscall_64+0x61/0xa0 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7ff3f059bf79
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ff3f145f028 EFLAGS: 00000246
RAX: fffffffffffffffc RBX: 00007ff3f0815fa0 RCX: 00007ff3f059bf79
RDX: 00002000000004c0 RSI: 0000000000000000 RDI: 0000000000000008
RBP: 00007ff3f06327e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff3f0816038 R14: 00007ff3f0815fa0 R15: 00007ffc23685be8