rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-....: (10500 ticks this GP) idle=0b1/1/0x4000000000000000 softirq=176797/176797 fqs=5183 (t=10502 jiffies g=334273 q=7242) NMI backtrace for cpu 0 CPU: 0 PID: 17120 Comm: syz-executor.5 Not tainted 5.15.0-rc7-next-20211029-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __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:105 nmi_trigger_cpumask_backtrace+0x1ae/0x220 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x25e/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:3922 [inline] rcu_sched_clock_irq.cold+0x9d/0x746 kernel/rcu/tree.c:2620 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 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:seq_printf+0xaf/0x240 fs/seq_file.c:405 Code: f3 65 48 8b 04 25 28 00 00 00 48 89 84 24 90 00 00 00 31 c0 e8 62 0c a4 ff 48 8d 45 10 48 89 44 24 40 48 8d 84 24 98 00 00 00 <48> 89 44 24 48 4c 89 f8 48 c1 e8 03 c7 44 24 38 10 00 00 00 42 80 RSP: 0018:ffffc9000389f820 EFLAGS: 00000246 RAX: ffffc9000389f8b8 RBX: ffff88808089e5c8 RCX: ffffc9000f561000 RDX: 0000000000040000 RSI: ffffffff81d3bfce RDI: ffff88808089e5c8 RBP: ffffc9000389f910 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff88d82172 R11: 0000000000000000 R12: 1ffff92000713f07 R13: dffffc0000000000 R14: dffffc0000000000 R15: ffff88808089e5e0 __io_uring_show_fdinfo fs/io_uring.c:10157 [inline] io_uring_show_fdinfo+0x47f/0x1372 fs/io_uring.c:10240 seq_show+0x58d/0x800 fs/proc/fd.c:68 seq_read_iter+0x4f6/0x1240 fs/seq_file.c:230 seq_read+0x3e0/0x5b0 fs/seq_file.c:162 do_loop_readv_writev fs/read_write.c:746 [inline] do_loop_readv_writev fs/read_write.c:733 [inline] do_iter_read+0x501/0x760 fs/read_write.c:788 vfs_readv+0xe5/0x150 fs/read_write.c:906 do_preadv fs/read_write.c:998 [inline] __do_sys_preadv fs/read_write.c:1048 [inline] __se_sys_preadv fs/read_write.c:1043 [inline] __x64_sys_preadv+0x231/0x310 fs/read_write.c:1043 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: 0033:0x7f1425e33ae9 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 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f1423367188 EFLAGS: 00000246 ORIG_RAX: 0000000000000127 RAX: ffffffffffffffda RBX: 00007f1425f470e0 RCX: 00007f1425e33ae9 RDX: 0000000000000001 RSI: 00000000200001c0 RDI: 0000000000000004 RBP: 00007f1425e8df25 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fff661b3cdf R14: 00007f1423367300 R15: 0000000000022000 ---------------- Code disassembly (best guess): 0: f3 65 48 8b 04 25 28 repz mov %gs:0x28,%rax 7: 00 00 00 a: 48 89 84 24 90 00 00 mov %rax,0x90(%rsp) 11: 00 12: 31 c0 xor %eax,%eax 14: e8 62 0c a4 ff callq 0xffa40c7b 19: 48 8d 45 10 lea 0x10(%rbp),%rax 1d: 48 89 44 24 40 mov %rax,0x40(%rsp) 22: 48 8d 84 24 98 00 00 lea 0x98(%rsp),%rax 29: 00 * 2a: 48 89 44 24 48 mov %rax,0x48(%rsp) <-- trapping instruction 2f: 4c 89 f8 mov %r15,%rax 32: 48 c1 e8 03 shr $0x3,%rax 36: c7 44 24 38 10 00 00 movl $0x10,0x38(%rsp) 3d: 00 3e: 42 rex.X 3f: 80 .byte 0x80