rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-....: (10500 ticks this GP) idle=ec3/1/0x4000000000000000 softirq=78994/78994 fqs=5245 (t=10502 jiffies g=120885 q=2272) NMI backtrace for cpu 1 CPU: 1 PID: 8607 Comm: syz-executor.5 Not tainted 5.16.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: <IRQ> __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:111 nmi_trigger_cpumask_backtrace+0x16a/0x280 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x22d/0x390 kernel/rcu/tree_stall.h:343 print_cpu_stall kernel/rcu/tree_stall.h:627 [inline] check_cpu_stall kernel/rcu/tree_stall.h:711 [inline] rcu_pending kernel/rcu/tree.c:3878 [inline] rcu_sched_clock_irq+0x1e33/0x2bc0 kernel/rcu/tree.c:2597 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:1428 __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 </IRQ> <TASK> asm_sysvec_apic_timer_interrupt+0x12/0x20 RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline] RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202 Code: d1 52 fd ff 90 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 2e f7 4f f7 48 89 df e8 36 a8 51 f7 e8 81 02 75 f7 fb bf 01 00 00 00 <e8> 96 00 44 f7 65 8b 05 b7 49 ec 75 85 c0 74 02 5b c3 e8 3c 31 ea RSP: 0018:ffffc90002bff570 EFLAGS: 00000282 RAX: a9ac30704b4a0800 RBX: ffffffff8cc5c4d8 RCX: ffffffff81667321 RDX: dffffc0000000000 RSI: 0000000000000001 RDI: 0000000000000001 RBP: ffffc90002bff7b0 R08: dffffc0000000000 R09: fffffbfff1ff41de R10: fffffbfff1ff41de R11: 0000000000000000 R12: ffffc90002bff680 R13: dffffc0000000000 R14: ffffffff8cc5c4c0 R15: 0000000000000006 rwsem_down_write_slowpath+0xcbd/0x1480 kernel/locking/rwsem.c:1127 __down_write_common kernel/locking/rwsem.c:1268 [inline] __down_write kernel/locking/rwsem.c:1277 [inline] down_write+0x163/0x170 kernel/locking/rwsem.c:1524 kernfs_remove_by_name_ns+0x24/0x90 fs/kernfs/dir.c:1540 kernfs_remove_by_name include/linux/kernfs.h:570 [inline] remove_files fs/sysfs/group.c:28 [inline] sysfs_remove_group+0xf7/0x280 fs/sysfs/group.c:288 sysfs_remove_groups+0x5b/0xb0 fs/sysfs/group.c:312 __kobject_del+0x84/0x310 lib/kobject.c:611 kobject_del+0x41/0x60 lib/kobject.c:643 ext4_fill_super+0xe819/0xf360 fs/ext4/super.c:5019 mount_bdev+0x26c/0x3a0 fs/super.c:1370 legacy_get_tree+0xea/0x180 fs/fs_context.c:610 vfs_get_tree+0x86/0x270 fs/super.c:1500 do_new_mount fs/namespace.c:2988 [inline] path_mount+0x1986/0x2c30 fs/namespace.c:3318 do_mount fs/namespace.c:3331 [inline] __do_sys_mount fs/namespace.c:3539 [inline] __se_sys_mount+0x308/0x3c0 fs/namespace.c:3516 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: 0033:0x7fb1d47ad3ca Code: 48 c7 c2 bc ff ff ff f7 d8 64 89 02 b8 ff ff ff ff eb d2 e8 b8 04 00 00 0f 1f 84 00 00 00 00 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fb1d3120f88 EFLAGS: 00000206 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 0000000020000200 RCX: 00007fb1d47ad3ca RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007fb1d3120fe0 RBP: 00007fb1d3121020 R08: 00007fb1d3121020 R09: 0000000020000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000020000000 R13: 0000000020000100 R14: 00007fb1d3120fe0 R15: 00000000200000c0 </TASK> ---------------- Code disassembly (best guess): 0: d1 52 fd rcll -0x3(%rdx) 3: ff 90 53 48 89 fb callq *-0x476b7ad(%rax) 9: 48 83 c7 18 add $0x18,%rdi d: 48 8b 74 24 08 mov 0x8(%rsp),%rsi 12: e8 2e f7 4f f7 callq 0xf74ff745 17: 48 89 df mov %rbx,%rdi 1a: e8 36 a8 51 f7 callq 0xf751a855 1f: e8 81 02 75 f7 callq 0xf77502a5 24: fb sti 25: bf 01 00 00 00 mov $0x1,%edi * 2a: e8 96 00 44 f7 callq 0xf74400c5 <-- trapping instruction 2f: 65 8b 05 b7 49 ec 75 mov %gs:0x75ec49b7(%rip),%eax # 0x75ec49ed 36: 85 c0 test %eax,%eax 38: 74 02 je 0x3c 3a: 5b pop %rbx 3b: c3 retq 3c: e8 .byte 0xe8 3d: 3c 31 cmp $0x31,%al 3f: ea (bad)