rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (0 ticks this GP) idle=3ed/1/0x4000000000000000 softirq=33374/33374 fqs=4 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P2971/1:b..l P18574/1:b..l (detected by 1, t=10502 jiffies, g=50117, q=44) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 3055 Comm: systemd-timesyn Not tainted 5.15.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:instrument_atomic_read include/linux/instrumented.h:71 [inline] RIP: 0010:test_bit include/asm-generic/bitops/instrumented-non-atomic.h:134 [inline] RIP: 0010:hlock_class kernel/locking/lockdep.c:199 [inline] RIP: 0010:__lock_acquire+0x12ee/0x2b00 kernel/locking/lockdep.c:5012 Code: 44 24 38 8a 04 38 84 c0 0f 85 2b 12 00 00 48 8b 44 24 20 8b 18 81 e3 ff 1f 00 00 48 89 d8 48 c1 e8 06 48 8d 3c c5 00 8e d1 8f 08 00 00 00 e8 f8 ce 69 00 48 0f a3 1d a0 7b 6d 0e 72 32 48 c7 RSP: 0018:ffffc90000007980 EFLAGS: 00000007 RAX: 000000000000002d RBX: 0000000000000b75 RCX: ffffffff81640fc0 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8fd18f68 RBP: ffffc90000007ad0 R08: dffffc0000000000 R09: fffffbfff1fa31c3 R10: fffffbfff1fa31c3 R11: 0000000000000000 R12: ffff88801a6a0000 R13: ffff88801a6a0a20 R14: ffffffff8f6673e0 R15: 960d9c1b3bb0c0bd FS: 00007f872cba68c0(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f8fbe68f018 CR3: 000000001faa6000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x19f/0x4d0 kernel/locking/lockdep.c:5625 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:363 [inline] advance_sched+0x4c/0x930 net/sched/sch_taprio.c:710 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x50b/0xa60 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x3b3/0x1040 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0xf9/0x270 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 RIP: 0010:lock_acquire+0x21f/0x4d0 kernel/locking/lockdep.c:5629 Code: 08 4c 89 f7 e8 b2 e4 69 00 f6 84 24 81 00 00 00 02 0f 85 13 02 00 00 41 f7 c4 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 04 2f 00 00 00 00 43 c7 44 2f 09 00 00 00 00 43 c7 44 2f 11 RSP: 0018:ffffc900012dfbc0 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 1ffff9200025bf88 RCX: ffff88801a6a09f0 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc900012dfd18 R08: dffffc0000000000 R09: fffffbfff1fa31c3 R10: fffffbfff1fa31c3 R11: 0000000000000000 R12: 0000000000000246 R13: 1ffff9200025bf80 R14: ffffc900012dfc40 R15: dffffc0000000000 __fs_reclaim_acquire mm/page_alloc.c:4539 [inline] fs_reclaim_acquire+0x77/0x110 mm/page_alloc.c:4553 might_alloc include/linux/sched/mm.h:198 [inline] slab_pre_alloc_hook mm/slab.h:492 [inline] slab_alloc_node mm/slub.c:3120 [inline] slab_alloc mm/slub.c:3214 [inline] kmem_cache_alloc+0x43/0x300 mm/slub.c:3219 sock_alloc_inode+0x17/0xb0 net/socket.c:303 alloc_inode fs/inode.c:237 [inline] new_inode_pseudo+0x61/0x220 fs/inode.c:938 sock_alloc net/socket.c:626 [inline] __sock_create+0x12b/0x8d0 net/socket.c:1428 sock_create net/socket.c:1515 [inline] __sys_socket+0x133/0x380 net/socket.c:1557 __do_sys_socket net/socket.c:1566 [inline] __se_sys_socket net/socket.c:1564 [inline] __x64_sys_socket+0x76/0x80 net/socket.c:1564 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f872bf9bf17 Code: 73 01 c3 48 8b 0d 81 ef 2a 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 29 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 51 ef 2a 00 f7 d8 64 89 01 48 RSP: 002b:00007fff360e58a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000029 RAX: ffffffffffffffda RBX: 0000563fbc56e630 RCX: 00007f872bf9bf17 RDX: 0000000000000000 RSI: 0000000000080002 RDI: 0000000000000002 RBP: 00007fff360e58c0 R08: 0000563fbc2dc260 R09: 00000000ffffffff R10: 00007fff360e58dc R11: 0000000000000246 R12: 0000000000000000 R13: 00007fff360e58f0 R14: 0000000000000066 R15: 0000000000000000 task:syz-executor.4 state:R running task stack:26768 pid:18574 ppid: 6926 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xc8d/0x1270 kernel/sched/core.c:6287 preempt_schedule_common kernel/sched/core.c:6459 [inline] preempt_schedule+0x14d/0x190 kernel/sched/core.c:6484 preempt_schedule_thunk+0x16/0x18 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline] _raw_spin_unlock_irqrestore+0x128/0x130 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:418 [inline] timerfd_clock_was_set+0x1d3/0x2b0 fs/timerfd.c:113 clock_was_set+0x8a0/0x940 kernel/time/hrtimer.c:980 do_settimeofday64+0x618/0x7a0 kernel/time/timekeeping.c:1327 __do_sys_clock_settime kernel/time/posix-timers.c:1079 [inline] __se_sys_clock_settime kernel/time/posix-timers.c:1067 [inline] __x64_sys_clock_settime+0x23d/0x280 kernel/time/posix-timers.c:1067 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f8fbe58a8d9 RSP: 002b:00007f8fbbb01188 EFLAGS: 00000246 ORIG_RAX: 00000000000000e3 RAX: ffffffffffffffda RBX: 00007f8fbe68ef60 RCX: 00007f8fbe58a8d9 RDX: 0000000000000000 RSI: 0000000020000080 RDI: 0000000000000000 RBP: 00007f8fbe5e4cb4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffd6104377f R14: 00007f8fbbb01300 R15: 0000000000022000 task:systemd-udevd state:R running task stack:19728 pid: 2971 ppid: 1 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xc8d/0x1270 kernel/sched/core.c:6287 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6687 irqentry_exit+0x56/0x90 kernel/entry/common.c:425 asm_sysvec_apic_timer_interrupt+0x12/0x20 RIP: 0010:lock_acquire+0x21f/0x4d0 kernel/locking/lockdep.c:5629 Code: 08 4c 89 f7 e8 b2 e4 69 00 f6 84 24 81 00 00 00 02 0f 85 13 02 00 00 41 f7 c4 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 04 2f 00 00 00 00 43 c7 44 2f 09 00 00 00 00 43 c7 44 2f 11 RSP: 0018:ffffc9000225f740 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 1ffff9200044bef8 RCX: ffff88801a6a5f70 RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc9000225f898 R08: dffffc0000000000 R09: fffffbfff1fa31c1 R10: fffffbfff1fa31c1 R11: 0000000000000000 R12: 0000000000000246 R13: 1ffff9200044bef0 R14: ffffc9000225f7c0 R15: dffffc0000000000 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:267 rcu_read_lock include/linux/rcupdate.h:687 [inline] dput+0x58/0x6e0 fs/dcache.c:874 path_put fs/namei.c:557 [inline] terminate_walk+0x3dc/0x570 fs/namei.c:676 path_lookupat+0x371/0x6c0 fs/namei.c:2466 filename_lookup+0x270/0x640 fs/namei.c:2478 user_path_at_empty+0x40/0x1a0 fs/namei.c:2801 user_path_at include/linux/namei.h:57 [inline] vfs_statx+0x10a/0x3f0 fs/stat.c:221 vfs_fstatat fs/stat.c:243 [inline] vfs_lstat include/linux/fs.h:3356 [inline] __do_sys_newlstat fs/stat.c:398 [inline] __se_sys_newlstat+0xba/0x750 fs/stat.c:392 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7fc02ea9c335 RSP: 002b:00007fff16e3cf68 EFLAGS: 00000246 ORIG_RAX: 0000000000000006 RAX: ffffffffffffffda RBX: 000055c34659fb40 RCX: 00007fc02ea9c335 RDX: 00007fff16e3cfa0 RSI: 00007fff16e3cfa0 RDI: 000055c34659eb40 RBP: 00007fff16e3d060 R08: 00007fc02ed5b228 R09: 0000000000001010 R10: 00007fc02ed5ab58 R11: 0000000000000246 R12: 000055c34659eb40 R13: 000055c34659eb5a R14: 000055c3465aefd5 R15: 000055c3465aefda rcu: rcu_preempt kthread starved for 10494 jiffies! g50117 f0x0 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:26296 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xc8d/0x1270 kernel/sched/core.c:6287 schedule+0x14b/0x210 kernel/sched/core.c:6366 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1881 rcu_gp_fqs_loop+0x1fd/0x770 kernel/rcu/tree.c:1957 rcu_gp_kthread+0xa5/0x350 kernel/rcu/tree.c:2130 kthread+0x453/0x480 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 rcu: Stack dump where RCU GP kthread last ran: NMI backtrace for cpu 1 CPU: 1 PID: 10968 Comm: kworker/u4:7 Not tainted 5.15.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events_unbound toggle_allocation_gate Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1dc/0x2d8 lib/dump_stack.c:106 nmi_cpu_backtrace+0x45f/0x490 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x16a/0x280 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_check_gp_kthread_starvation+0x1ff/0x270 kernel/rcu/tree_stall.h:481 print_other_cpu_stall kernel/rcu/tree_stall.h:586 [inline] check_cpu_stall kernel/rcu/tree_stall.h:729 [inline] rcu_pending kernel/rcu/tree.c:3880 [inline] rcu_sched_clock_irq+0x23d5/0x2bc0 kernel/rcu/tree.c:2599 update_process_times+0x197/0x200 kernel/time/timer.c:1785 tick_sched_handle kernel/time/tick-sched.c:226 [inline] tick_sched_timer+0x27d/0x420 kernel/time/tick-sched.c:1421 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x4cb/0xa60 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x3b3/0x1040 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0xf9/0x270 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 RIP: 0010:csd_lock_wait kernel/smp.c:440 [inline] RIP: 0010:smp_call_function_many_cond+0xbb7/0xda0 kernel/smp.c:969 Code: e8 ae 9f 0b 00 41 83 e7 01 49 bf 00 00 00 00 00 fc ff df 75 0e e8 89 9b 0b 00 eb 4c 0f 1f 80 00 00 00 00 f3 90 42 0f b6 04 3b <84> c0 75 11 41 f7 45 00 01 00 00 00 74 2b e8 66 9b 0b 00 eb e4 44 RSP: 0018:ffffc900187bf820 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 1ffff11017387305 RCX: ffff888022f30000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc900187bf960 R08: ffffffff8176d702 R09: ffffffff843540e0 R10: 0000000000000009 R11: ffff888022f30000 R12: 0000000000000000 R13: ffff8880b9c39828 R14: ffff8880b9d325c0 R15: dffffc0000000000 on_each_cpu_cond_mask+0x3b/0x80 kernel/smp.c:1135 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:929 [inline] text_poke_bp_batch+0x310/0x940 arch/x86/kernel/alternative.c:1114 text_poke_flush arch/x86/kernel/alternative.c:1268 [inline] text_poke_finish+0x16/0x30 arch/x86/kernel/alternative.c:1275 arch_jump_label_transform_apply+0x13/0x20 arch/x86/kernel/jump_label.c:146 static_key_enable_cpuslocked+0x12d/0x250 kernel/jump_label.c:177 static_key_enable+0x16/0x20 kernel/jump_label.c:190 toggle_allocation_gate+0xbf/0x460 mm/kfence/core.c:626 process_one_work+0x853/0x1140 kernel/workqueue.c:2297 worker_thread+0xac1/0x1320 kernel/workqueue.c:2444 kthread+0x453/0x480 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 ---------------- Code disassembly (best guess): 0: 44 24 38 rex.R and $0x38,%al 3: 8a 04 38 mov (%rax,%rdi,1),%al 6: 84 c0 test %al,%al 8: 0f 85 2b 12 00 00 jne 0x1239 e: 48 8b 44 24 20 mov 0x20(%rsp),%rax 13: 8b 18 mov (%rax),%ebx 15: 81 e3 ff 1f 00 00 and $0x1fff,%ebx 1b: 48 89 d8 mov %rbx,%rax 1e: 48 c1 e8 06 shr $0x6,%rax 22: 48 8d 3c c5 00 8e d1 lea -0x702e7200(,%rax,8),%rdi 29: 8f * 2a: be 08 00 00 00 mov $0x8,%esi <-- trapping instruction 2f: e8 f8 ce 69 00 callq 0x69cf2c 34: 48 0f a3 1d a0 7b 6d bt %rbx,0xe6d7ba0(%rip) # 0xe6d7bdc 3b: 0e 3c: 72 32 jb 0x70 3e: 48 rex.W 3f: c7 .byte 0xc7