rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 1, t=10502 jiffies, g=94257, q=139) rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4295019486-4295008984), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10502 jiffies! g94257 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 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:26768 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xc8d/0x1270 kernel/sched/core.c:6287 schedule+0x14b/0x210 kernel/sched/core.c:6366 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1881 rcu_gp_fqs_loop+0x1fd/0x770 kernel/rcu/tree.c:1957 rcu_gp_kthread+0xa5/0x350 kernel/rcu/tree.c:2130 kthread+0x453/0x480 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 25850 Comm: syz-executor.4 Not tainted 5.14.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:get_current arch/x86/include/asm/current.h:15 [inline] RIP: 0010:write_comp_data kernel/kcov.c:217 [inline] RIP: 0010:__sanitizer_cov_trace_cmp8+0x4/0x90 kernel/kcov.c:264 Code: c1 e0 03 48 83 c8 18 48 89 34 01 4c 89 44 f9 18 49 ff c2 4c 89 11 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 4c 8b 04 24 <65> 48 8b 14 25 c0 ef 01 00 65 8b 05 74 75 7f 7e a9 00 01 ff 00 74 RSP: 0018:ffffc90000007c78 EFLAGS: 00000046 RAX: 1ffff1100e27c505 RBX: 1770f6392ee1ec72 RCX: dffffc0000000000 RDX: ffff888075aeb900 RSI: 1770f6392ee1ec72 RDI: 1770f6392ee1ec72 RBP: 1770f6392ee1ec72 R08: ffffffff8840946f R09: 0000000000000003 R10: fffff52000000f81 R11: 0000000000000004 R12: ffff8880713e2828 R13: ffff8880713e2810 R14: ffff88807c941510 R15: 1ffff1100f9282a0 FS: 00007f3103051700(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000568000 CR3: 0000000070f14000 CR4: 00000000001506f0 Call Trace: should_restart_cycle net/sched/sch_taprio.c:661 [inline] advance_sched+0x32f/0x930 net/sched/sch_taprio.c:734 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x50b/0xa60 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x3b3/0x1040 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0xf9/0x270 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 RIP: 0010:smack_cred security/smack/smack.h:336 [inline] RIP: 0010:smack_key_alloc+0x2f/0x90 security/smack/smack_lsm.c:4238 Code: 54 53 49 89 f7 49 89 fe 49 bc 00 00 00 00 00 fc ff df e8 a4 86 ad fd 49 81 c7 88 00 00 00 4c 89 f8 48 c1 e8 03 42 80 3c 20 00 <74> 08 4c 89 ff e8 f7 dd f8 fd 48 63 1d 60 bb 63 08 49 03 1f 48 89 RSP: 0018:ffffc9000341fb08 EFLAGS: 00000246 RAX: 1ffff1100e1b5ff1 RBX: ffffffff8c38bb38 RCX: 0000000000040000 RDX: ffffc90012216000 RSI: 00000000000010d3 RDI: 00000000000010d4 RBP: ffffffff8c38bb50 R08: ffffffff83cf50af R09: ffff88823bccef20 R10: ffffed1047799de6 R11: 0000000000000000 R12: dffffc0000000000 R13: dffffc0000000000 R14: ffff88823bccee80 R15: ffff888070daff88 security_key_alloc+0x56/0xb0 security/security.c:2520 key_alloc+0x7c5/0xf10 security/keys/key.c:314 keyring_alloc+0x40/0xa0 security/keys/keyring.c:526 install_process_keyring_to_cred security/keys/process_keys.c:275 [inline] install_process_keyring security/keys/process_keys.c:300 [inline] lookup_user_key+0x4d6/0x1710 security/keys/process_keys.c:653 __do_sys_add_key security/keys/keyctl.c:126 [inline] __se_sys_add_key+0x2f3/0x480 security/keys/keyctl.c:74 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x4665f9 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:00007f3103051188 EFLAGS: 00000246 ORIG_RAX: 00000000000000f8 RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665f9 RDX: 0000000020000a80 RSI: 0000000020000080 RDI: 0000000020000a40 RBP: 00000000004bfcc4 R08: fffffffffffffffe R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000246 R12: 000000000056bf80 R13: 00007ffdfdab915f R14: 00007f3103051300 R15: 0000000000022000 vkms_vblank_simulate: vblank timer overrun vkms_vblank_simulate: vblank timer overrun vkms_vblank_simulate: vblank timer overrun ---------------- Code disassembly (best guess): 0: c1 e0 03 shl $0x3,%eax 3: 48 83 c8 18 or $0x18,%rax 7: 48 89 34 01 mov %rsi,(%rcx,%rax,1) b: 4c 89 44 f9 18 mov %r8,0x18(%rcx,%rdi,8) 10: 49 ff c2 inc %r10 13: 4c 89 11 mov %r10,(%rcx) 16: c3 retq 17: 66 2e 0f 1f 84 00 00 nopw %cs:0x0(%rax,%rax,1) 1e: 00 00 00 21: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) 26: 4c 8b 04 24 mov (%rsp),%r8 * 2a: 65 48 8b 14 25 c0 ef mov %gs:0x1efc0,%rdx <-- trapping instruction 31: 01 00 33: 65 8b 05 74 75 7f 7e mov %gs:0x7e7f7574(%rip),%eax # 0x7e7f75ae 3a: a9 00 01 ff 00 test $0xff0100,%eax 3f: 74 .byte 0x74