rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-....: (1 GPs behind) idle=fe3/1/0x4000000000000000 softirq=65557/65558 fqs=5247 (t=10502 jiffies g=82205 q=1143) NMI backtrace for cpu 0 CPU: 0 PID: 26970 Comm: syz-executor.2 Not tainted 5.16.0-rc8-next-20220105-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+0xcd/0x134 lib/dump_stack.c:106 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x262/0x3f0 kernel/rcu/tree_stall.h:343 print_cpu_stall kernel/rcu/tree_stall.h:604 [inline] check_cpu_stall kernel/rcu/tree_stall.h:688 [inline] rcu_pending kernel/rcu/tree.c:3921 [inline] rcu_sched_clock_irq.cold+0x5c/0x759 kernel/rcu/tree.c:2626 update_process_times+0x16d/0x200 kernel/time/timer.c:1785 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:226 tick_sched_timer+0x1b0/0x2d0 kernel/time/tick-sched.c:1428 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x1c0/0xe50 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1097 </IRQ> <TASK> asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:signal_pending_state include/linux/sched/signal.h:387 [inline] RIP: 0010:rwsem_down_write_slowpath+0x576/0x1110 kernel/locking/rwsem.c:1120 Code: 80 00 00 00 f0 4c 0f b1 65 00 0f 85 e1 03 00 00 41 83 e4 04 0f 84 26 02 00 00 c6 84 24 e8 00 00 00 01 4c 89 f7 e8 aa 72 fd 07 <f7> 44 24 04 01 01 00 00 74 71 be 08 00 00 00 4c 89 ef e8 f3 6b 67 RSP: 0018:ffffc9001093f6b0 EFLAGS: 00000286 RAX: 0000000080000000 RBX: dffffc0000000000 RCX: 0000000000000000 RDX: 0000000000000001 RSI: 0000000000000001 RDI: 0000000000000001 RBP: ffff888010c678d8 R08: 0000000000000001 R09: ffffffff8ffbb94f R10: 0000000000000001 R11: 0000000000000001 R12: 1ffffffff1701e30 R13: ffff888075df57c0 R14: ffff888010c678f0 R15: ffffc90002cc7ac8 __down_write_common kernel/locking/rwsem.c:1259 [inline] __down_write_common kernel/locking/rwsem.c:1256 [inline] __down_write kernel/locking/rwsem.c:1268 [inline] down_write+0x135/0x150 kernel/locking/rwsem.c:1515 kernfs_drain fs/kernfs/dir.c:486 [inline] __kernfs_remove+0x5fc/0xb20 fs/kernfs/dir.c:1367 kernfs_remove_by_name_ns+0xa8/0x110 fs/kernfs/dir.c:1565 kernfs_remove_by_name include/linux/kernfs.h:574 [inline] remove_files+0x96/0x1c0 fs/sysfs/group.c:28 sysfs_remove_group+0x87/0x170 fs/sysfs/group.c:288 sysfs_remove_groups fs/sysfs/group.c:312 [inline] sysfs_remove_groups+0x5c/0xa0 fs/sysfs/group.c:304 __kobject_del+0x89/0x200 lib/kobject.c:611 kobject_del lib/kobject.c:643 [inline] kobject_del+0x3c/0x60 lib/kobject.c:635 __ext4_fill_super fs/ext4/super.c:5453 [inline] ext4_fill_super+0xb044/0xe800 fs/ext4/super.c:5551 get_tree_bdev+0x440/0x760 fs/super.c:1292 vfs_get_tree+0x89/0x2f0 fs/super.c:1497 do_new_mount fs/namespace.c:3010 [inline] path_mount+0x1320/0x1fa0 fs/namespace.c:3340 do_mount fs/namespace.c:3353 [inline] __do_sys_mount fs/namespace.c:3561 [inline] __se_sys_mount fs/namespace.c:3538 [inline] __x64_sys_mount+0x27f/0x300 fs/namespace.c:3538 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f0be1fef3ca 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:00007f0be0962f88 EFLAGS: 00000206 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 0000000020000200 RCX: 00007f0be1fef3ca RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007f0be0962fe0 RBP: 00007f0be0963020 R08: 00007f0be0963020 R09: 0000000020000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000020000000 R13: 0000000020000100 R14: 00007f0be0962fe0 R15: 00000000200000c0 </TASK> ---------------- Code disassembly (best guess): 0: 80 00 00 addb $0x0,(%rax) 3: 00 f0 add %dh,%al 5: 4c 0f b1 65 00 cmpxchg %r12,0x0(%rbp) a: 0f 85 e1 03 00 00 jne 0x3f1 10: 41 83 e4 04 and $0x4,%r12d 14: 0f 84 26 02 00 00 je 0x240 1a: c6 84 24 e8 00 00 00 movb $0x1,0xe8(%rsp) 21: 01 22: 4c 89 f7 mov %r14,%rdi 25: e8 aa 72 fd 07 callq 0x7fd72d4 * 2a: f7 44 24 04 01 01 00 testl $0x101,0x4(%rsp) <-- trapping instruction 31: 00 32: 74 71 je 0xa5 34: be 08 00 00 00 mov $0x8,%esi 39: 4c 89 ef mov %r13,%rdi 3c: e8 .byte 0xe8 3d: f3 repz 3e: 6b .byte 0x6b 3f: 67 addr32