rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 1, t=10502 jiffies, g=19317, q=52) rcu: All QSes seen, last rcu_preempt kthread activity 10503 (4294960116-4294949613), jiffies_till_next_fqs=1, root ->qsmask 0x0 syz-executor.4 R running task 25160 9515 7492 0x00004000 Call Trace: sched_show_task kernel/sched/core.c:5956 [inline] sched_show_task.cold+0x2e2/0x343 kernel/sched/core.c:5931 print_other_cpu_stall kernel/rcu/tree_stall.h:430 [inline] check_cpu_stall kernel/rcu/tree_stall.h:558 [inline] rcu_pending kernel/rcu/tree.c:3225 [inline] rcu_sched_clock_irq.cold+0xb9b/0xcfa kernel/rcu/tree.c:2296 update_process_times+0x25/0x60 kernel/time/timer.c:1727 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:176 tick_sched_timer+0x4e/0x140 kernel/time/tick-sched.c:1320 __run_hrtimer kernel/time/hrtimer.c:1520 [inline] __hrtimer_run_queues+0x5ca/0xed0 kernel/time/hrtimer.c:1584 hrtimer_interrupt+0x312/0x770 kernel/time/hrtimer.c:1646 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1113 [inline] smp_apic_timer_interrupt+0x15b/0x600 arch/x86/kernel/apic/apic.c:1138 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829 RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:26 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:153 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x9/0x50 kernel/kcov.c:187 Code: cc 65 48 8b 04 25 00 1f 02 00 48 8b 80 f0 13 00 00 c3 0f 1f 44 00 00 66 2e 0f 1f 84 00 00 00 00 00 65 48 8b 04 25 00 1f 02 00 <65> 8b 15 98 e9 8e 7e 81 e2 00 01 1f 00 48 8b 34 24 75 2b 8b 90 d8 RSP: 0018:ffffc900019c7570 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: ffff888089d860c0 RBX: 1ffff92000338eb1 RCX: ffffffff81c28954 RDX: 000000003a1a83f9 RSI: 000000003a1a83f9 RDI: 000000003a1a83f9 RBP: ffffc900019c7610 R08: ffff888089d860c0 R09: fffffbfff185dd3e R10: ffffffff8c2ee9ef R11: fffffbfff185dd3d R12: ffff8880638b28b8 R13: ffff88809ff02840 R14: 0000000000000000 R15: 000000005ec99964 file_update_time+0x173/0x480 fs/inode.c:1897 file_modified fs/inode.c:1933 [inline] file_modified+0x7d/0xa0 fs/inode.c:1918 ext4_write_checks+0x4f/0x80 fs/ext4/file.c:249 ext4_buffered_write_iter+0xbe/0x450 fs/ext4/file.c:265 ext4_file_write_iter+0x1ec/0x13f0 fs/ext4/file.c:642 call_write_iter include/linux/fs.h:1907 [inline] do_iter_readv_writev+0x5a8/0x850 fs/read_write.c:694 do_iter_write fs/read_write.c:999 [inline] do_iter_write+0x18b/0x600 fs/read_write.c:980 vfs_iter_write+0x70/0xa0 fs/read_write.c:1040 iter_file_splice_write+0x684/0xb00 fs/splice.c:760 do_splice_from fs/splice.c:863 [inline] direct_splice_actor+0x115/0x160 fs/splice.c:1037 splice_direct_to_actor+0x38c/0x980 fs/splice.c:992 do_splice_direct+0x1b4/0x280 fs/splice.c:1080 do_sendfile+0x555/0xc50 fs/read_write.c:1521 __do_sys_sendfile64 fs/read_write.c:1576 [inline] __se_sys_sendfile64 fs/read_write.c:1568 [inline] __x64_sys_sendfile64+0x149/0x210 fs/read_write.c:1568 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 RIP: 0033:0x45ca29 Code: 0d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 db b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f5b7261dc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00000000004fc540 RCX: 000000000045ca29 RDX: 00000000200001c0 RSI: 0000000000000005 RDI: 0000000000000005 RBP: 000000000078c0e0 R08: 0000000000000000 R09: 0000000000000000 R10: 00008080fffffffe R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000008dc R14: 00000000004cba16 R15: 00007f5b7261e6d4 rcu: rcu_preempt kthread starved for 10553 jiffies! g19317 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 28848 10 2 0x80004000 Call Trace: