rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (32 ticks this GP) idle=033/1/0x4000000000000000 softirq=10899/10899 fqs=0 (detected by 0, t=10502 jiffies, g=15309, q=340) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 5571 Comm: syz.4.319 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 RIP: 0010:rcu_dynticks_curr_cpu_in_eqs kernel/rcu/tree.c:331 [inline] RIP: 0010:rcu_is_watching+0x11/0xa0 kernel/rcu/tree.c:1123 Code: 41 5f 5d c3 e8 a0 99 57 08 41 f7 c7 00 02 00 00 75 bd eb bc e8 80 99 57 08 41 57 41 56 53 65 ff 05 7c a0 9d 7e e8 7f a9 57 08 <89> c3 83 f8 08 73 5c 49 bf 00 00 00 00 00 fc ff df 4c 8d 34 dd 20 RSP: 0018:ffffc90000dd0c80 EFLAGS: 00000082 RAX: 0000000000000001 RBX: 0000000000000001 RCX: f83f89df35448300 RDX: 0000000000010000 RSI: ffffffff8a79f960 RDI: ffffffff8a79f920 RBP: ffff88807d5dc360 R08: dffffc0000000000 R09: 1ffffffff203a818 R10: dffffc0000000000 R11: fffffbfff203a819 R12: ffff88807d5dc2e8 R13: dffffc0000000000 R14: ffff88807d5dc000 R15: 18a6efb274fdf068 FS: 00007f9a951926c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00002000002f6030 CR3: 0000000020655000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_read_lock include/linux/rcupdate.h:741 [inline] advance_sched+0x6e3/0x940 net/sched/sch_taprio.c:769 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x4f2/0xb70 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1811 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:lock_acquire+0x208/0x400 kernel/locking/lockdep.c:5627 Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3d 04 f8 0f 85 f1 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 43 c7 44 3d 08 00 00 00 00 65 48 8b 04 RSP: 0018:ffffc9000332f480 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 0000000000000000 RCX: f83f89df35448300 RDX: 0000000000000000 RSI: ffffffff8a2b3a20 RDI: ffffffff8a79f980 RBP: ffffc9000332f588 R08: dffffc0000000000 R09: 1ffffffff203a82e R10: dffffc0000000000 R11: fffffbfff203a82f R12: ffff88807f0d9da0 R13: 1ffff92000665e9c R14: 0000000000000246 R15: dffffc0000000000 __mutex_lock_common+0x1e3/0x2400 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 __unix_dgram_recvmsg+0x205/0xd90 net/unix/af_unix.c:2312 ____sys_recvmsg+0x2cd/0x5e0 net/socket.c:-1 ___sys_recvmsg+0x21a/0x5c0 net/socket.c:2706 do_recvmmsg+0x382/0x850 net/socket.c:2800 __sys_recvmmsg net/socket.c:2879 [inline] __do_sys_recvmmsg net/socket.c:2902 [inline] __se_sys_recvmmsg net/socket.c:2895 [inline] __x64_sys_recvmmsg+0x195/0x250 net/socket.c:2895 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: 0033:0x7f9a96f59819 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:00007f9a95192028 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007f9a971d3090 RCX: 00007f9a96f59819 RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000004 RBP: 00007f9a96fefc91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f9a971d3128 R14: 00007f9a971d3090 R15: 00007ffca03d8628 rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g15309 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=6519 rcu: rcu_preempt kthread starved for 10502 jiffies! g15309 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27152 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2117 rcu_gp_fqs_loop+0x2be/0x11d0 kernel/rcu/tree.c:1972 rcu_gp_kthread+0x9b/0x370 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: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 5571 Comm: syz.4.319 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 RIP: 0010:bytes_is_nonzero mm/kasan/generic.c:87 [inline] RIP: 0010:memory_is_nonzero mm/kasan/generic.c:102 [inline] RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:128 [inline] RIP: 0010:memory_is_poisoned mm/kasan/generic.c:159 [inline] RIP: 0010:check_region_inline mm/kasan/generic.c:180 [inline] RIP: 0010:kasan_check_range+0x8a/0x290 mm/kasan/generic.c:189 Code: 1c 21 49 89 df 4d 29 df 49 83 ff 10 7f 29 4d 85 ff 0f 84 38 01 00 00 4c 89 cb 48 f7 d3 4c 01 f3 41 80 3b 00 0f 85 86 01 00 00 <49> ff c3 48 ff c3 75 ee e9 18 01 00 00 44 89 dd 83 e5 07 0f 84 b5 RSP: 0018:ffffc90000dd08b0 EFLAGS: 00000046 RAX: 0000000000000001 RBX: ffffffffffffffff RCX: ffffffff815d12d3 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff901d40c0 RBP: ffffc90000dd0b30 R08: ffffffff901d40c7 R09: 1ffffffff203a818 R10: dffffc0000000000 R11: fffffbfff203a818 R12: dffffc0000000001 R13: ffff88802bf53b80 R14: 1ffffffff203a818 R15: 0000000000000001 FS: 00007f9a951926c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00002000002f6030 CR3: 0000000020655000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: instrument_atomic_read include/linux/instrumented.h:71 [inline] test_bit include/asm-generic/bitops/instrumented-non-atomic.h:134 [inline] __lock_acquire+0xdc3/0x7d10 kernel/locking/lockdep.c:4982 lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:313 rcu_read_lock include/linux/rcupdate.h:740 [inline] advance_sched+0x6ca/0x940 net/sched/sch_taprio.c:769 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x4f2/0xb70 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1811 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:lock_acquire+0x208/0x400 kernel/locking/lockdep.c:5627 Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3d 04 f8 0f 85 f1 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 43 c7 44 3d 08 00 00 00 00 65 48 8b 04 RSP: 0018:ffffc9000332f480 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 0000000000000000 RCX: f83f89df35448300 RDX: 0000000000000000 RSI: ffffffff8a2b3a20 RDI: ffffffff8a79f980 RBP: ffffc9000332f588 R08: dffffc0000000000 R09: 1ffffffff203a82e R10: dffffc0000000000 R11: fffffbfff203a82f R12: ffff88807f0d9da0 R13: 1ffff92000665e9c R14: 0000000000000246 R15: dffffc0000000000 __mutex_lock_common+0x1e3/0x2400 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 __unix_dgram_recvmsg+0x205/0xd90 net/unix/af_unix.c:2312 ____sys_recvmsg+0x2cd/0x5e0 net/socket.c:-1 ___sys_recvmsg+0x21a/0x5c0 net/socket.c:2706 do_recvmmsg+0x382/0x850 net/socket.c:2800 __sys_recvmmsg net/socket.c:2879 [inline] __do_sys_recvmmsg net/socket.c:2902 [inline] __se_sys_recvmmsg net/socket.c:2895 [inline] __x64_sys_recvmmsg+0x195/0x250 net/socket.c:2895 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: 0033:0x7f9a96f59819 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:00007f9a95192028 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007f9a971d3090 RCX: 00007f9a96f59819 RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000004 RBP: 00007f9a96fefc91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f9a971d3128 R14: 00007f9a971d3090 R15: 00007ffca03d8628