rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-...!: (1 GPs behind) idle=9da/1/0x4000000000000002 softirq=171195/171196 fqs=21 (t=10500 jiffies g=295273 q=225) rcu: rcu_preempt kthread starved for 10451 jiffies! g295273 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 29056 10 2 0x80004000 Call Trace: context_switch kernel/sched/core.c:2818 [inline] __schedule+0x7cb/0x1560 kernel/sched/core.c:3445 schedule+0xa8/0x260 kernel/sched/core.c:3509 schedule_timeout+0x486/0xc50 kernel/time/timer.c:1807 rcu_gp_fqs_loop kernel/rcu/tree.c:1589 [inline] rcu_gp_kthread+0x9b2/0x18b0 kernel/rcu/tree.c:1746 kthread+0x354/0x420 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 NMI backtrace for cpu 1 CPU: 1 PID: 20231 Comm: syz-executor.3 Not tainted 5.2.0-rc4+ #30 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x172/0x1f0 lib/dump_stack.c:113 nmi_cpu_backtrace.cold+0x63/0xa4 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1be/0x236 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x183/0x1cf kernel/rcu/tree_stall.h:254 print_cpu_stall kernel/rcu/tree_stall.h:455 [inline] check_cpu_stall kernel/rcu/tree_stall.h:529 [inline] rcu_pending kernel/rcu/tree.c:2625 [inline] rcu_sched_clock_irq.cold+0x4d1/0xbfd kernel/rcu/tree.c:2161 update_process_times+0x32/0x80 kernel/time/timer.c:1639 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:167 tick_sched_timer+0x47/0x130 kernel/time/tick-sched.c:1298 __run_hrtimer kernel/time/hrtimer.c:1389 [inline] __hrtimer_run_queues+0x33b/0xdd0 kernel/time/hrtimer.c:1451 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1509 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline] smp_apic_timer_interrupt+0x111/0x550 arch/x86/kernel/apic/apic.c:1066 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:806 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:767 [inline] RIP: 0010:kmem_cache_free+0xab/0x260 mm/slab.c:3699 Code: e8 8a 28 00 00 84 c0 74 77 41 f7 c5 00 02 00 00 74 4f e8 38 21 cd ff 48 83 3d 50 75 09 07 00 0f 84 ab 01 00 00 4c 89 ef 57 9d <0f> 1f 44 00 00 4c 8b 6d 08 0f 1f 44 00 00 65 8b 05 70 92 58 7e 83 RSP: 0018:ffff88806592f228 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 RAX: 0000000000000007 RBX: ffff888051184898 RCX: 1ffff1100d1c918e RDX: 0000000000000000 RSI: ffff888068e48c50 RDI: 0000000000000286 RBP: ffff88806592f248 R08: ffff888068e48380 R09: ffff888068e48c70 R10: 0000000000000000 R11: 0000000000000000 R12: ffff888219ef3240 R13: 0000000000000286 R14: ffffffff81cecf03 R15: 0000000000025800 mb_cache_entry_create+0x3d3/0x950 fs/mbcache.c:104 ext4_xattr_block_cache_insert fs/ext4/xattr.c:2985 [inline] ext4_xattr_block_get fs/ext4/xattr.c:537 [inline] ext4_xattr_get+0x5ad/0xa00 fs/ext4/xattr.c:652 ext4_xattr_security_get+0x32/0x40 fs/ext4/xattr_security.c:20 __vfs_getxattr+0xee/0x150 fs/xattr.c:311 cap_inode_need_killpriv+0x43/0x70 security/commoncap.c:300 security_inode_need_killpriv+0x63/0xa0 security/security.c:1252 dentry_needs_remove_privs.part.0+0x24/0x80 fs/inode.c:1802 dentry_needs_remove_privs include/linux/fs.h:3481 [inline] file_remove_privs+0x32d/0x530 fs/inode.c:1842 __generic_file_write_iter+0x15e/0x630 mm/filemap.c:3281 ext4_file_write_iter+0x332/0x1070 fs/ext4/file.c:266 call_write_iter include/linux/fs.h:1872 [inline] do_iter_readv_writev+0x5f8/0x8f0 fs/read_write.c:693 do_iter_write fs/read_write.c:970 [inline] do_iter_write+0x184/0x610 fs/read_write.c:951 vfs_iter_write+0x77/0xb0 fs/read_write.c:983 iter_file_splice_write+0x65c/0xbd0 fs/splice.c:746 do_splice_from fs/splice.c:848 [inline] direct_splice_actor+0x123/0x190 fs/splice.c:1020 splice_direct_to_actor+0x366/0x970 fs/splice.c:975 do_splice_direct+0x1da/0x2a0 fs/splice.c:1063 do_sendfile+0x597/0xd00 fs/read_write.c:1464 __do_sys_sendfile64 fs/read_write.c:1525 [inline] __se_sys_sendfile64 fs/read_write.c:1511 [inline] __x64_sys_sendfile64+0x1dd/0x220 fs/read_write.c:1511 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4592c9 Code: fd 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 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f7298cb6c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00000000004592c9 RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000004 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 00008000fffffffe R11: 0000000000000246 R12: 00007f7298cb76d4 R13: 00000000004c689d R14: 00000000004db828 R15: 00000000ffffffff sched: RT throttling activated