rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (10498 ticks this GP) idle=8b3/1/0x4000000000000000 softirq=29852/29852 fqs=0 (t=10500 jiffies g=42513 q=36) rcu: rcu_preempt kthread starved for 10500 jiffies! g42513 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:28648 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4986 [inline] __schedule+0xab2/0x4d90 kernel/sched/core.c:6296 schedule+0xd2/0x260 kernel/sched/core.c:6369 schedule_timeout+0x14a/0x2a0 kernel/time/timer.c:1881 rcu_gp_fqs_loop+0x186/0x810 kernel/rcu/tree.c:1971 rcu_gp_kthread+0x1de/0x320 kernel/rcu/tree.c:2144 kthread+0x2e9/0x3a0 kernel/kthread.c:381 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 11713 Comm: syz-executor.4 Not tainted 5.16.0-rc6-next-20211223-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:match_held_lock+0xe/0xc0 kernel/locking/lockdep.c:5089 Code: 48 c7 c7 20 fc ab 89 e8 3c 09 bd ff e8 26 c1 cc ff 31 c0 5d c3 0f 1f 80 00 00 00 00 53 48 89 fb 48 83 ec 08 48 39 77 10 74 6a <66> f7 47 22 f0 ff 74 5a 48 8b 46 08 48 89 f7 48 85 c0 74 42 8b 15 RSP: 0018:ffffc9000614f1e8 EFLAGS: 00000087 RAX: 0000000000000005 RBX: ffff888036824510 RCX: 0000000000000001 RDX: 0000000000000000 RSI: ffffffff8bb82360 RDI: ffff888036824510 RBP: ffffffff8bb82360 R08: 0000000000000000 R09: ffffffff8d931dd7 R10: fffffbfff1b263ba R11: 0000000000000000 R12: ffff888036823a80 R13: ffff8880368244e8 R14: 00000000ffffffff R15: ffff888036824510 FS: 00007f5676d41700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2e939000 CR3: 000000001a0a8000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __lock_is_held kernel/locking/lockdep.c:5380 [inline] lock_is_held_type+0xa7/0x140 kernel/locking/lockdep.c:5682 lock_is_held include/linux/lockdep.h:283 [inline] rcu_read_lock_sched_held+0x3a/0x70 kernel/rcu/update.c:125 trace_lock_acquire include/trace/events/lock.h:13 [inline] lock_acquire+0x442/0x510 kernel/locking/lockdep.c:5610 rcu_lock_acquire include/linux/rcupdate.h:268 [inline] rcu_read_lock include/linux/rcupdate.h:694 [inline] mapping_get_entry mm/filemap.c:1892 [inline] __filemap_get_folio+0x127/0xef0 mm/filemap.c:1957 pagecache_get_page+0x2e/0x280 mm/folio-compat.c:125 ext4_da_write_begin+0x3bb/0xba0 fs/ext4/inode.c:2959 generic_perform_write+0x205/0x510 mm/filemap.c:3809 ext4_buffered_write_iter+0x1ac/0x3b0 fs/ext4/file.c:269 ext4_file_write_iter+0x423/0x14e0 fs/ext4/file.c:681 call_write_iter include/linux/fs.h:2079 [inline] do_iter_readv_writev+0x47a/0x750 fs/read_write.c:725 do_iter_write+0x188/0x710 fs/read_write.c:851 vfs_iter_write+0x70/0xa0 fs/read_write.c:892 iter_file_splice_write+0x723/0xc70 fs/splice.c:689 do_splice_from fs/splice.c:767 [inline] direct_splice_actor+0x110/0x180 fs/splice.c:936 splice_direct_to_actor+0x34b/0x8c0 fs/splice.c:891 do_splice_direct+0x1b3/0x280 fs/splice.c:979 do_sendfile+0xaf2/0x1250 fs/read_write.c:1245 __do_sys_sendfile64 fs/read_write.c:1310 [inline] __se_sys_sendfile64 fs/read_write.c:1296 [inline] __x64_sys_sendfile64+0x1cc/0x210 fs/read_write.c:1296 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: 0033:0x7f56783cbe99 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:00007f5676d41168 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007f56784def60 RCX: 00007f56783cbe99 RDX: 0000000000000000 RSI: 000000000000000f RDI: 0000000000000005 RBP: 00007f5678425ff1 R08: 0000000000000000 R09: 0000000000000000 R10: 00008400fffffffa R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffcdf98007f R14: 00007f5676d41300 R15: 0000000000022000 NMI backtrace for cpu 0 CPU: 0 PID: 11715 Comm: syz-executor.3 Not tainted 5.16.0-rc6-next-20211223-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: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:3927 [inline] rcu_sched_clock_irq.cold+0x9d/0x746 kernel/rcu/tree.c:2625 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:arch_is_kernel_initmem_freed arch/x86/include/asm/sections.h:27 [inline] RIP: 0010:static_obj+0x1e/0xc0 kernel/locking/lockdep.c:812 Code: f5 fa 07 66 0f 1f 84 00 00 00 00 00 48 c7 c0 00 aa 99 8b 55 48 89 fd 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 53 80 3c 10 00 <75> 7b 48 c7 c0 00 60 a2 90 48 39 e8 0f 97 c3 48 83 3d 8b b5 3d 0a RSP: 0018:ffffc9000678f240 EFLAGS: 00000246 RAX: 1ffffffff1733540 RBX: ffffffff90503900 RCX: 0000000000000000 RDX: dffffc0000000000 RSI: ffffffff89bac3e0 RDI: ffffffff9057a0a0 RBP: ffffffff9057a0a0 R08: 0000000000000002 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff9057a0a0 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000408c40 lockdep_init_map_type+0x2c3/0x7b0 kernel/locking/lockdep.c:4810 lockdep_init_map_waits include/linux/lockdep.h:195 [inline] lockdep_init_map_wait include/linux/lockdep.h:202 [inline] __raw_spin_lock_init+0x36/0x110 kernel/locking/spinlock_debug.c:24 __spin_lock_init include/linux/spinlock.h:332 [inline] alloc_buffer_head+0x98/0x140 fs/buffer.c:3365 alloc_page_buffers+0x285/0x7b0 fs/buffer.c:832 create_empty_buffers+0x2c/0x1060 fs/buffer.c:1597 ext4_block_write_begin+0x117a/0x16e0 fs/ext4/inode.c:1061 ext4_da_write_begin+0x3e9/0xba0 fs/ext4/inode.c:2967 generic_perform_write+0x205/0x510 mm/filemap.c:3809 ext4_buffered_write_iter+0x1ac/0x3b0 fs/ext4/file.c:269 ext4_file_write_iter+0x423/0x14e0 fs/ext4/file.c:681 call_write_iter include/linux/fs.h:2079 [inline] do_iter_readv_writev+0x47a/0x750 fs/read_write.c:725 do_iter_write+0x188/0x710 fs/read_write.c:851 vfs_iter_write+0x70/0xa0 fs/read_write.c:892 iter_file_splice_write+0x723/0xc70 fs/splice.c:689 do_splice_from fs/splice.c:767 [inline] direct_splice_actor+0x110/0x180 fs/splice.c:936 splice_direct_to_actor+0x34b/0x8c0 fs/splice.c:891 do_splice_direct+0x1b3/0x280 fs/splice.c:979 do_sendfile+0xaf2/0x1250 fs/read_write.c:1245 __do_sys_sendfile64 fs/read_write.c:1310 [inline] __se_sys_sendfile64 fs/read_write.c:1296 [inline] __x64_sys_sendfile64+0x1cc/0x210 fs/read_write.c:1296 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: 0033:0x7f718f6dee99 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:00007f718e054168 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007f718f7f1f60 RCX: 00007f718f6dee99 RDX: 0000000000000000 RSI: 000000000000000f RDI: 0000000000000005 RBP: 00007f718f738ff1 R08: 0000000000000000 R09: 0000000000000000 R10: 00008400fffffffa R11: 0000000000000246 R12: 0000000000000000 R13: 00007fffa843a9bf R14: 00007f718e054300 R15: 0000000000022000 sched: RT throttling activated ---------------- Code disassembly (best guess): 0: 48 c7 c7 20 fc ab 89 mov $0xffffffff89abfc20,%rdi 7: e8 3c 09 bd ff callq 0xffbd0948 c: e8 26 c1 cc ff callq 0xffccc137 11: 31 c0 xor %eax,%eax 13: 5d pop %rbp 14: c3 retq 15: 0f 1f 80 00 00 00 00 nopl 0x0(%rax) 1c: 53 push %rbx 1d: 48 89 fb mov %rdi,%rbx 20: 48 83 ec 08 sub $0x8,%rsp 24: 48 39 77 10 cmp %rsi,0x10(%rdi) 28: 74 6a je 0x94 * 2a: 66 f7 47 22 f0 ff testw $0xfff0,0x22(%rdi) <-- trapping instruction 30: 74 5a je 0x8c 32: 48 8b 46 08 mov 0x8(%rsi),%rax 36: 48 89 f7 mov %rsi,%rdi 39: 48 85 c0 test %rax,%rax 3c: 74 42 je 0x80 3e: 8b .byte 0x8b 3f: 15 .byte 0x15