rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (0 ticks this GP) idle=e2e/1/0x4000000000000000 softirq=77487/77487 fqs=0 (detected by 0, t=10502 jiffies, g=137841, q=24) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 2589 Comm: modprobe Not tainted 5.9.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__lock_acquire+0x1cf/0x5780 kernel/locking/lockdep.c:4336 Code: 6f 7a d3 48 c1 fa 03 48 89 74 24 28 48 0f af d1 48 89 54 24 08 8b 54 24 10 4c 8d 14 92 49 c1 e2 03 85 d2 74 47 4a 8d 54 16 d8 <48> b9 00 00 00 00 00 fc ff df 48 8d 7a 20 48 89 fe 48 c1 ee 03 0f RSP: 0018:ffffc90000da8a78 EFLAGS: 00000002 RAX: 0000000000000003 RBX: 0000000000000001 RCX: d37a6f4de9bd37a7 RDX: ffff8880a4b84a50 RSI: ffff8880a4b84a28 RDI: ffffffff8d47a790 RBP: ffff8880a4b84140 R08: 0000000000000001 R09: 0000000000000001 R10: 0000000000000050 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: ffffffff8d47a788 R15: 0000000000000000 FS: 00007fb1a9a8e4c0(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffdde72ad90 CR3: 000000008dc1a000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x1f3/0xae0 kernel/locking/lockdep.c:5006 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x94/0xce kernel/locking/spinlock.c:159 debug_object_activate+0x12e/0x3e0 lib/debugobjects.c:636 debug_hrtimer_activate kernel/time/hrtimer.c:420 [inline] debug_activate kernel/time/hrtimer.c:480 [inline] enqueue_hrtimer+0x27/0x3f0 kernel/time/hrtimer.c:969 __run_hrtimer kernel/time/hrtimer.c:1541 [inline] __hrtimer_run_queues+0xc1e/0xfc0 kernel/time/hrtimer.c:1588 hrtimer_interrupt+0x334/0x940 kernel/time/hrtimer.c:1650 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline] __sysvec_apic_timer_interrupt+0x147/0x5f0 arch/x86/kernel/apic/apic.c:1097 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:706 __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline] run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline] sysvec_apic_timer_interrupt+0xb2/0xf0 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:581 RIP: 0010:write_comp_data+0x2f/0x80 kernel/kcov.c:218 Code: 05 96 c3 8b 7e 65 48 8b 34 25 c0 fe 01 00 a9 00 01 ff 00 74 0f f6 c4 01 74 59 8b 86 2c 14 00 00 85 c0 74 4f 8b 86 08 14 00 00 <83> f8 03 75 44 48 8b 86 10 14 00 00 8b b6 0c 14 00 00 4c 8b 00 48 RSP: 0018:ffffc9000871f9e8 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffffffff8a464f38 RCX: ffffffff835df78e RDX: 0000000000000000 RSI: ffff8880a4b84140 RDI: 0000000000000005 RBP: dffffc0000000000 R08: 0000000000000001 R09: ffff8880a4b84a20 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: ffff888098012578 R14: 0000000000000081 R15: 70646f6d2f637465 security_inode_permission+0x9e/0xf0 security/security.c:1258 inode_permission.part.0+0x113/0x410 fs/namei.c:471 inode_permission fs/namei.c:444 [inline] may_lookup fs/namei.c:1569 [inline] link_path_walk.part.0+0x1f2/0xc20 fs/namei.c:2125 link_path_walk fs/namei.c:2111 [inline] path_lookupat+0xb7/0x830 fs/namei.c:2332 filename_lookup+0x19f/0x560 fs/namei.c:2366 user_path_at include/linux/namei.h:59 [inline] vfs_statx+0x14e/0x390 fs/stat.c:202 vfs_stat include/linux/fs.h:3173 [inline] __do_sys_newstat+0x91/0x110 fs/stat.c:361 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7fb1a95ac295 Code: 00 00 00 e8 5d 01 00 00 48 83 c4 18 c3 0f 1f 84 00 00 00 00 00 83 ff 01 48 89 f0 77 30 48 89 c7 48 89 d6 b8 04 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 03 f3 c3 90 48 8b 15 d1 db 2b 00 f7 d8 64 89 RSP: 002b:00007ffdde72ad88 EFLAGS: 00000246 ORIG_RAX: 0000000000000004 RAX: ffffffffffffffda RBX: 0000556ec4ee3090 RCX: 00007fb1a95ac295 RDX: 00007ffdde72ae50 RSI: 00007ffdde72ae50 RDI: 0000556ec3643e99 RBP: 0000556ec3643e99 R08: 0000000000000003 R09: 0000000000000020 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 0000556ec384b068 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10502 jiffies! g137841 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:29096 pid: 10 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:3778 [inline] __schedule+0xec9/0x2280 kernel/sched/core.c:4527 schedule+0xd0/0x2a0 kernel/sched/core.c:4602 schedule_timeout+0x148/0x250 kernel/time/timer.c:1879 rcu_gp_fqs_loop kernel/rcu/tree.c:1888 [inline] rcu_gp_kthread+0xb2c/0x1ca0 kernel/rcu/tree.c:2058 kthread+0x3b5/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294