rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 0, t=10502 jiffies, g=69985, q=84) rcu: All QSes seen, last rcu_preempt kthread activity 10494 (4294988638-4294978144), jiffies_till_next_fqs=1, root ->qsmask 0x0 syz-executor.2 R running task 25488 18984 7299 0x00004000 Call Trace: sched_show_task kernel/sched/core.c:5952 [inline] sched_show_task.cold+0x2e2/0x343 kernel/sched/core.c:5927 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:3030 [inline] rcu_sched_clock_irq.cold+0xb35/0xc55 kernel/rcu/tree.c:2276 update_process_times+0x25/0x60 kernel/time/timer.c:1726 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:171 tick_sched_timer+0x4e/0x140 kernel/time/tick-sched.c:1314 __run_hrtimer kernel/time/hrtimer.c:1517 [inline] __hrtimer_run_queues+0x32c/0xdd0 kernel/time/hrtimer.c:1579 hrtimer_interrupt+0x312/0x770 kernel/time/hrtimer.c:1641 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1119 [inline] smp_apic_timer_interrupt+0x15b/0x600 arch/x86/kernel/apic/apic.c:1144 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829 RIP: 0010:__sanitizer_cov_trace_const_cmp8+0x4/0x20 kernel/kcov.c:280 Code: 84 00 00 00 00 00 48 8b 0c 24 89 f2 89 fe bf 05 00 00 00 e9 ce fe ff ff 0f 1f 40 00 66 2e 0f 1f 84 00 00 00 00 00 48 8b 0c 24 <48> 89 f2 48 89 fe bf 07 00 00 00 e9 ac fe ff ff 66 90 66 2e 0f 1f RSP: 0018:ffffc90008746ff0 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: dffffc0000000000 RBX: ffffea00019c7840 RCX: ffffffff81946546 RDX: 1ffffd4000338f09 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffea00019c7840 R08: ffff8880a42c0280 R09: ffffed1015cc7074 R10: ffffed1015cc7073 R11: ffff8880ae63839b R12: ffffea00019c7848 R13: 0000000000000000 R14: ffffea00021ff9c8 R15: 00000000000003ff compound_head include/linux/page-flags.h:176 [inline] PageReferenced include/linux/page-flags.h:315 [inline] mark_page_accessed+0x86/0x1050 mm/swap.c:377 touch_buffer fs/buffer.c:63 [inline] __find_get_block+0x317/0xe90 fs/buffer.c:1340 __getblk_gfp+0x33/0xae0 fs/buffer.c:1358 sb_getblk include/linux/buffer_head.h:325 [inline] __ext4_get_inode_loc+0x3fe/0x1320 fs/ext4/inode.c:4263 ext4_reserve_inode_write+0xc6/0x230 fs/ext4/inode.c:5609 ext4_mark_inode_dirty+0x174/0x900 fs/ext4/inode.c:5775 ext4_dirty_inode+0xe7/0x120 fs/ext4/inode.c:5814 __mark_inode_dirty+0x65e/0x1350 fs/fs-writeback.c:2258 mark_inode_dirty include/linux/fs.h:2184 [inline] generic_write_end+0x2f4/0x3d0 fs/buffer.c:2199 ext4_da_write_end+0x217/0xbd0 fs/ext4/inode.c:3092 generic_perform_write+0x2c0/0x4e0 mm/filemap.c:3298 ext4_buffered_write_iter+0x1f7/0x450 fs/ext4/file.c:270 ext4_file_write_iter+0x1ec/0x13f0 fs/ext4/file.c:642 call_write_iter include/linux/fs.h:1902 [inline] do_iter_readv_writev+0x59c/0x840 fs/read_write.c:693 do_iter_write fs/read_write.c:998 [inline] do_iter_write+0x185/0x600 fs/read_write.c:979 vfs_iter_write+0x70/0xa0 fs/read_write.c:1039 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+0x1a8/0x270 fs/splice.c:1080 do_sendfile+0x549/0xc40 fs/read_write.c:1520 __do_sys_sendfile64 fs/read_write.c:1575 [inline] __se_sys_sendfile64 fs/read_write.c:1567 [inline] __x64_sys_sendfile64+0x149/0x210 fs/read_write.c:1567 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c849 Code: ad b6 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 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f50d0a15c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007f50d0a166d4 RCX: 000000000045c849 RDX: 00000000200001c0 RSI: 0000000000000005 RDI: 0000000000000005 RBP: 000000000076c040 R08: 0000000000000000 R09: 0000000000000000 R10: 00008080fffffffe R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000008d4 R14: 00000000004cb786 R15: 000000000076c04c rcu: rcu_preempt kthread starved for 10554 jiffies! g69985 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 29384 10 2 0x80004000 Call Trace: schedule+0xd0/0x2a0 kernel/sched/core.c:4154 schedule_timeout+0x474/0xba0 kernel/time/timer.c:1895 rcu_gp_fqs_loop kernel/rcu/tree.c:1658 [inline] rcu_gp_kthread+0x9d9/0x17d0 kernel/rcu/tree.c:1818 kthread+0x357/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352