rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): (detected by 0, t=10502 jiffies, g=90041, q=50) rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4295013187-4295002685), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10502 jiffies! g90041 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:29032 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4339 [inline] __schedule+0x916/0x23e0 kernel/sched/core.c:5147 schedule+0xcf/0x270 kernel/sched/core.c:5226 schedule_timeout+0x14a/0x250 kernel/time/timer.c:1892 rcu_gp_fqs_loop kernel/rcu/tree.c:2004 [inline] rcu_gp_kthread+0xd07/0x2300 kernel/rcu/tree.c:2177 kthread+0x3b1/0x4a0 kernel/kthread.c:313 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 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: 29061 Comm: syz-executor.4 Not tainted 5.13.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:native_apic_mem_write+0x8/0x10 arch/x86/include/asm/apic.h:110 Code: c7 40 87 41 8f e8 08 59 86 00 eb b0 66 0f 1f 44 00 00 be 01 00 00 00 e9 86 f4 2b 00 cc cc cc cc cc cc 89 ff 89 b7 00 c0 5f ff 0f 1f 80 00 00 00 00 48 b8 00 00 00 00 00 fc ff df 53 89 fb 48 RSP: 0018:ffffc90000dd8ea8 EFLAGS: 00000046 RAX: dffffc0000000000 RBX: ffffffff8b0da8c0 RCX: 0000000000000020 RDX: 1ffffffff161b51a RSI: 00000000000000e9 RDI: 0000000000000380 RBP: ffff8880b9d1f2c0 R08: 000000000000003f R09: 0000000000000000 R10: ffffffff8166ffa7 R11: 0000000000000000 R12: 00000000000000e9 R13: 0000000000000020 R14: ffff8880b9d26380 R15: 7fffffffffffffff FS: 00007fc09f4db700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b33530000 CR3: 0000000083956000 CR4: 00000000001526e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: apic_write arch/x86/include/asm/apic.h:393 [inline] lapic_next_event+0x4d/0x80 arch/x86/kernel/apic/apic.c:472 clockevents_program_event+0x254/0x370 kernel/time/clockevents.c:334 tick_program_event+0xac/0x140 kernel/time/tick-oneshot.c:44 hrtimer_interrupt+0x414/0xa00 kernel/time/hrtimer.c:1676 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1089 [inline] __sysvec_apic_timer_interrupt+0x146/0x540 arch/x86/kernel/apic/apic.c:1106 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1100 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:647 RIP: 0010:lock_acquire+0x1ef/0x740 kernel/locking/lockdep.c:5480 Code: 47 a8 7e 83 f8 01 0f 85 ee 03 00 00 9c 58 f6 c4 02 0f 85 d9 03 00 00 48 83 7c 24 08 00 74 01 fb 48 b8 00 00 00 00 00 fc ff df <48> 01 c3 48 c7 03 00 00 00 00 48 c7 43 08 00 00 00 00 48 8b 84 24 RSP: 0018:ffffc900018c7120 EFLAGS: 00000206 RAX: dffffc0000000000 RBX: 1ffff92000318e26 RCX: ffffffff81596307 RDX: 1ffff11014404196 RSI: 0000000000000001 RDI: 0000000000000000 RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffff9022a957 R10: fffffbfff204552a R11: 0000000000000000 R12: 0000000000000000 R13: ffff88808271d890 R14: 0000000000000000 R15: 0000000000000000 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:354 [inline] ext4_do_update_inode fs/ext4/inode.c:5033 [inline] ext4_mark_iloc_dirty+0x213/0x38c0 fs/ext4/inode.c:5724 __ext4_mark_inode_dirty+0x222/0x8d0 fs/ext4/inode.c:5918 ext4_dirty_inode+0xd4/0x110 fs/ext4/inode.c:5947 __mark_inode_dirty+0x6e3/0x10f0 fs/fs-writeback.c:2274 mark_inode_dirty include/linux/fs.h:2404 [inline] generic_write_end+0x316/0x4f0 fs/buffer.c:2223 ext4_da_write_end+0x20f/0xb50 fs/ext4/inode.c:3110 generic_perform_write+0x2c0/0x4f0 mm/filemap.c:3671 ext4_buffered_write_iter+0x244/0x4d0 fs/ext4/file.c:269 ext4_file_write_iter+0x423/0x14e0 fs/ext4/file.c:680 call_write_iter include/linux/fs.h:2114 [inline] do_iter_readv_writev+0x46f/0x740 fs/read_write.c:740 do_iter_write+0x188/0x670 fs/read_write.c:866 vfs_iter_write+0x70/0xa0 fs/read_write.c:907 iter_file_splice_write+0x6fa/0xc10 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+0x9f0/0x1110 fs/read_write.c:1260 __do_sys_sendfile64 fs/read_write.c:1325 [inline] __se_sys_sendfile64 fs/read_write.c:1311 [inline] __x64_sys_sendfile64+0x1cc/0x210 fs/read_write.c:1311 do_syscall_64+0x3a/0xb0 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x4665d9 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:00007fc09f4db188 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 00000000004665d9 RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000005 RBP: 00000000004bfcb9 R08: 0000000000000000 R09: 0000000000000000 R10: 00008400fffffffa R11: 0000000000000246 R12: 000000000056bf60 R13: 00007ffe5b0fd61f R14: 00007fc09f4db300 R15: 0000000000022000