rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: (detected by 0, t=10503 jiffies, g=69505, q=179 ncpus=2) rcu: All QSes seen, last rcu_preempt kthread activity 10503 (4295113959-4295103456), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10503 jiffies! g69505 f0x2 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:25392 pid:17 tgid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5369 [inline] __schedule+0x17fb/0x4be0 kernel/sched/core.c:6756 __schedule_loop kernel/sched/core.c:6833 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6848 schedule_timeout+0x15a/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2045 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2247 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 21047 Comm: syz.7.3257 Not tainted 6.13.0-rc2-syzkaller-00018-g7cb1b4663150 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 RIP: 0010:task_irq_context kernel/locking/lockdep.c:4678 [inline] RIP: 0010:__lock_acquire+0x3c5/0x2100 kernel/locking/lockdep.c:5163 Code: 48 89 df e8 8d 90 88 00 48 8b 7c 24 08 48 be 00 00 00 00 00 fc ff df 48 8b 84 24 c8 00 00 00 48 89 9c 24 80 00 00 00 48 89 03 <65> 8b 05 60 e4 87 7e 31 db 85 c0 0f 95 c3 01 db 48 8b 44 24 40 4c RSP: 0018:ffffc90000a188f0 EFLAGS: 00000046 RAX: 0000000000000000 RBX: ffff888031f1c720 RCX: ffffffff9a374903 RDX: 0000000000000001 RSI: dffffc0000000000 RDI: ffff888031f1c6e0 RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000001 R10: dffffc0000000000 R11: fffffbfff203075f R12: ffffffff84c087df R13: 0000000000000005 R14: 0000000000000000 R15: ffffffff9a5bf518 FS: 00007f29eacaa6c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b30514ff8 CR3: 0000000037484000 CR4: 00000000003526f0 Call Trace: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162 debug_object_activate+0x17f/0x580 lib/debugobjects.c:818 debug_hrtimer_activate kernel/time/hrtimer.c:428 [inline] debug_activate kernel/time/hrtimer.c:469 [inline] enqueue_hrtimer+0x30/0x3c0 kernel/time/hrtimer.c:1076 __run_hrtimer kernel/time/hrtimer.c:1756 [inline] __hrtimer_run_queues+0x6cb/0xd30 kernel/time/hrtimer.c:1803 hrtimer_interrupt+0x403/0xa40 kernel/time/hrtimer.c:1865 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:finish_task_switch+0x1ea/0x870 kernel/sched/core.c:5243 Code: c9 50 e8 c9 06 0c 00 48 83 c4 08 4c 89 f7 e8 ed 39 00 00 0f 1f 44 00 00 4c 89 f7 e8 d0 57 54 0a e8 2b 96 38 00 fb 48 8b 5d c0 <48> 8d bb f8 15 00 00 48 89 f8 48 c1 e8 03 49 be 00 00 00 00 00 fc RSP: 0018:ffffc90003a1f1a8 EFLAGS: 00000286 RAX: b31f40ba343e8d00 RBX: ffff888031f1bc00 RCX: ffffffff9a374903 RDX: dffffc0000000000 RSI: ffffffff8c0a9760 RDI: ffffffff8c5ec300 RBP: ffffc90003a1f1f0 R08: ffffffff90183af7 R09: 1ffffffff203075e R10: dffffc0000000000 R11: fffffbfff203075f R12: 1ffff110170e7eac R13: dffffc0000000000 R14: ffff8880b873e740 R15: ffff8880b873f560 context_switch kernel/sched/core.c:5372 [inline] __schedule+0x1803/0x4be0 kernel/sched/core.c:6756 __schedule_loop kernel/sched/core.c:6833 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6848 schedule_timeout+0xb0/0x290 kernel/time/sleep_timeout.c:75 unix_wait_for_peer+0x250/0x340 net/unix/af_unix.c:1529 unix_dgram_sendmsg+0x127f/0x1f80 net/unix/af_unix.c:2131 sock_sendmsg_nosec net/socket.c:711 [inline] __sock_sendmsg+0x221/0x270 net/socket.c:726 ____sys_sendmsg+0x52a/0x7e0 net/socket.c:2583 ___sys_sendmsg net/socket.c:2637 [inline] __sys_sendmmsg+0x36a/0x720 net/socket.c:2726 __do_sys_sendmmsg net/socket.c:2753 [inline] __se_sys_sendmmsg net/socket.c:2750 [inline] __x64_sys_sendmmsg+0xa0/0xb0 net/socket.c:2750 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: 0033:0x7f29e9f7fed9 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:00007f29eacaa058 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 00007f29ea145fa0 RCX: 00007f29e9f7fed9 RDX: 0000000000000651 RSI: 0000000020000000 RDI: 0000000000000007 RBP: 00007f29e9ff3cc8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f29ea145fa0 R15: 00007ffe593ab688