rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: (detected by 1, t=10502 jiffies, g=5513, q=82) rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4295015017-4295004515), jiffies_till_next_fqs=1, root ->qsmask 0x0 syz-executor918 R running task 26560 7905 7883 0x00000000 Call Trace: sched_show_task kernel/sched/core.c:5338 [inline] sched_show_task.cold+0x291/0x2fc kernel/sched/core.c:5313 print_other_cpu_stall kernel/rcu/tree.c:1313 [inline] check_cpu_stall kernel/rcu/tree.c:1441 [inline] rcu_pending kernel/rcu/tree.c:3103 [inline] rcu_sched_clock_irq.cold+0xa10/0xa4a kernel/rcu/tree.c:2544 update_process_times+0x32/0x80 kernel/time/timer.c:1635 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:161 tick_sched_timer+0x47/0x130 kernel/time/tick-sched.c:1271 __run_hrtimer kernel/time/hrtimer.c:1389 [inline] __hrtimer_run_queues+0x33e/0xde0 kernel/time/hrtimer.c:1451 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1509 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1035 [inline] smp_apic_timer_interrupt+0x120/0x570 arch/x86/kernel/apic/apic.c:1060 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807 RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x50 kernel/kcov.c:95 Code: 89 25 b4 7e ec 08 41 bc f4 ff ff ff e8 cd 5d ea ff 48 c7 05 9e 7e ec 08 00 00 00 00 e9 a4 e9 ff ff 90 90 90 90 90 90 90 90 90 <55> 48 89 e5 48 8b 75 08 65 48 8b 04 25 00 ee 01 00 65 8b 15 c8 60 RSP: 0018:ffff8880975af300 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: 0000000000000000 RBX: 000000000000000e RCX: ffffffff818b6bcc RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005 RBP: ffff8880975af358 R08: ffff8880a7c40040 R09: 0000000000000003 R10: ffffed1015d25bc7 R11: ffff8880ae92de3b R12: ffffea00020c67c0 R13: 0000000000100cca R14: dffffc0000000000 R15: 0000000000000000 grab_cache_page_write_begin+0x75/0xb0 mm/filemap.c:3249 ext4_da_write_begin+0x2d7/0xec0 fs/ext4/inode.c:3071 generic_perform_write+0x231/0x530 mm/filemap.c:3299 __generic_file_write_iter+0x25e/0x630 mm/filemap.c:3428 ext4_file_write_iter+0x346/0x11c0 fs/ext4/file.c:266 call_write_iter include/linux/fs.h:1866 [inline] do_iter_readv_writev+0x5e1/0x8e0 fs/read_write.c:681 do_iter_write fs/read_write.c:957 [inline] do_iter_write+0x184/0x610 fs/read_write.c:938 vfs_iter_write+0x77/0xb0 fs/read_write.c:970 iter_file_splice_write+0x662/0xbe0 fs/splice.c:745 do_splice_from fs/splice.c:847 [inline] direct_splice_actor+0x126/0x1a0 fs/splice.c:1019 splice_direct_to_actor+0x369/0x970 fs/splice.c:974 do_splice_direct+0x1da/0x2a0 fs/splice.c:1062 do_sendfile+0x597/0xd00 fs/read_write.c:1443 __do_sys_sendfile64 fs/read_write.c:1498 [inline] __se_sys_sendfile64 fs/read_write.c:1490 [inline] __x64_sys_sendfile64+0x15a/0x220 fs/read_write.c:1490 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x446989 Code: e8 0c e8 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 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 0f 83 5b 07 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f69fcde7da8 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00000000006dbc28 RCX: 0000000000446989 RDX: 0000000020000000 RSI: 0000000000000004 RDI: 0000000000000004 RBP: 00000000006dbc20 R08: 0000000000000000 R09: 0000000000000000 R10: 00008080fffffffe R11: 0000000000000246 R12: 00000000006dbc2c R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10502 jiffies! g5513 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 29304 10 2 0x80000000 Call Trace: context_switch kernel/sched/core.c:2877 [inline] __schedule+0x813/0x1cc0 kernel/sched/core.c:3518 schedule+0x92/0x180 kernel/sched/core.c:3562 schedule_timeout+0x4db/0xfd0 kernel/time/timer.c:1803 rcu_gp_fqs_loop kernel/rcu/tree.c:1971 [inline] rcu_gp_kthread+0x962/0x17b0 kernel/rcu/tree.c:2128 kthread+0x357/0x430 kernel/kthread.c:253 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352