rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 ticks this GP) idle=ebb4/1/0x4000000000000000 softirq=18550/18550 fqs=0 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6264/1:b..l rcu: (detected by 1, t=10502 jiffies, g=18213, q=251 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 7276 Comm: syz.1.370 Not tainted 6.14.0-rc7-syzkaller-00196-g88d324e69ea9 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:lock_acquire+0x24b/0x550 kernel/locking/lockdep.c:5854 Code: 4c 89 f7 e8 a7 c4 89 00 48 c7 44 24 60 00 00 00 00 9c 8f 44 24 60 42 80 3c 2b 00 74 08 4c 89 f7 e8 9a c3 89 00 f6 44 24 61 02 <0f> 85 85 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e RSP: 0018:ffffc90000007b00 EFLAGS: 00000046 RAX: 0000000000000001 RBX: 1ffff92000000f6c RCX: ffff888027bc64e8 RDX: dffffc0000000000 RSI: ffffffff8c2ac600 RDI: ffffffff8c802ce0 RBP: ffffc90000007c58 R08: ffffffff94517847 R09: 1ffffffff28a2f08 R10: dffffc0000000000 R11: fffffbfff28a2f09 R12: 1ffff92000000f68 R13: dffffc0000000000 R14: ffffc90000007b60 R15: 0000000000000046 FS: 00007f8f9ae1c6c0(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f8f9ae1bf98 CR3: 0000000033296000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] rcu_read_lock include/linux/rcupdate.h:849 [inline] advance_sched+0xa1e/0xca0 net/sched/sch_taprio.c:985 __run_hrtimer kernel/time/hrtimer.c:1801 [inline] __hrtimer_run_queues+0x59b/0xd30 kernel/time/hrtimer.c:1865 hrtimer_interrupt+0x403/0xa40 kernel/time/hrtimer.c:1927 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline] __sysvec_apic_timer_interrupt+0x110/0x420 arch/x86/kernel/apic/apic.c:1055 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0xd8/0x140 kernel/locking/spinlock.c:194 Code: 9c 8f 44 24 20 42 80 3c 23 00 74 08 4c 89 f7 e8 7e a1 22 f6 f6 44 24 21 02 75 52 41 f7 c7 00 02 00 00 74 01 fb bf 01 00 00 00 a3 8c 8b f5 65 8b 05 74 de ff 73 85 c0 74 43 48 c7 04 24 0e 36 RSP: 0018:ffffc90003eafba0 EFLAGS: 00000206 RAX: a3be21bbfc2c7500 RBX: 1ffff920007d5f78 RCX: ffffffff819d4b6a RDX: dffffc0000000000 RSI: ffffffff8c2ab3a0 RDI: 0000000000000001 RBP: ffffc90003eafc30 R08: ffffffff94517847 R09: 1ffffffff28a2f08 R10: dffffc0000000000 R11: fffffbfff28a2f09 R12: dffffc0000000000 R13: 1ffff920007d5f74 R14: ffffc90003eafbc0 R15: 0000000000000246 clock_was_set+0x686/0x810 kernel/time/hrtimer.c:984 do_settimeofday64+0x343/0x5e0 kernel/time/timekeeping.c:1381 __do_sys_clock_settime kernel/time/posix-timers.c:1135 [inline] __se_sys_clock_settime kernel/time/posix-timers.c:1119 [inline] __x64_sys_clock_settime+0x23a/0x280 kernel/time/posix-timers.c:1119 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f8f99f8d169 Code: 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 01 48 RSP: 002b:00007f8f9ae1c038 EFLAGS: 00000246 ORIG_RAX: 00000000000000e3 RAX: ffffffffffffffda RBX: 00007f8f9a1a5fa0 RCX: 00007f8f99f8d169 RDX: 0000000000000000 RSI: 0000200000003c80 RDI: 0000000000000000 RBP: 00007f8f9a00e2a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000001 R14: 00007f8f9a1a5fa0 R15: 00007ffd91f830f8 task:udevd state:R running task stack:24576 pid:6264 tgid:6264 ppid:5198 task_flags:0x400140 flags:0x00000002 Call Trace: context_switch kernel/sched/core.c:5378 [inline] __schedule+0x18bc/0x4c40 kernel/sched/core.c:6765 preempt_schedule_common+0x84/0xd0 kernel/sched/core.c:6944 preempt_schedule+0xe1/0xf0 kernel/sched/core.c:6968 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock_irqrestore+0x130/0x140 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] __wake_up_common_lock+0x18c/0x1e0 kernel/sched/wait.c:108 sock_def_readable+0x20f/0x5a0 net/core/sock.c:3493 unix_dgram_sendmsg+0xf1b/0x1df0 net/unix/af_unix.c:2164 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg+0x221/0x270 net/socket.c:733 sock_write_iter+0x2d7/0x3f0 net/socket.c:1137 new_sync_write fs/read_write.c:586 [inline] vfs_write+0xacf/0xd10 fs/read_write.c:679 ksys_write+0x18f/0x2b0 fs/read_write.c:731 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f0393116bf2 RSP: 002b:00007ffcd1531dd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f0393116bf2 RDX: 0000000000000000 RSI: 00007ffcd1531e2f RDI: 000000000000000a RBP: 00007ffcd1531e2f R08: 0000000000000001 R09: 0000000000000000 R10: 000000000000010f R11: 0000000000000246 R12: 000000000000000a R13: 00007f0393587ae0 R14: 0000000000000000 R15: 00005561c3f64910 rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g18213 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=8461 rcu: rcu_preempt kthread starved for 10502 jiffies! g18213 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:25784 pid:18 tgid:18 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5378 [inline] __schedule+0x18bc/0x4c40 kernel/sched/core.c:6765 __schedule_loop kernel/sched/core.c:6842 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6857 schedule_timeout+0x15a/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2024 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2226 kthread+0x7a9/0x920 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244