rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (1 GPs behind) idle=d15/1/0x4000000000000000 softirq=49515/49516 fqs=21 (t=10501 jiffies g=87957 q=152) rcu: rcu_preempt kthread starved for 10456 jiffies! g87957 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:28696 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4955 [inline] __schedule+0x940/0x26f0 kernel/sched/core.c:6236 schedule+0xd3/0x270 kernel/sched/core.c:6315 schedule_timeout+0x14a/0x2a0 kernel/time/timer.c:1881 rcu_gp_fqs_loop+0x186/0x810 kernel/rcu/tree.c:1955 rcu_gp_kthread+0x1de/0x320 kernel/rcu/tree.c:2128 kthread+0x405/0x4f0 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 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: 21756 Comm: syz-executor.0 Not tainted 5.15.0-rc2-next-20210920-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:rcu_read_lock_held_common kernel/rcu/update.c:120 [inline] RIP: 0010:rcu_read_lock_sched_held+0x2/0x70 kernel/rcu/update.c:123 Code: 49 c1 ec 09 49 83 f4 01 41 83 e4 01 44 89 e0 41 5c c3 45 31 e4 44 89 e0 41 5c c3 66 66 2e 0f 1f 84 00 00 00 00 00 66 90 41 54 <41> bc 01 00 00 00 e8 f3 83 d1 07 85 c0 75 06 44 89 e0 41 5c c3 e8 RSP: 0018:ffffc90005b2f5f0 EFLAGS: 00000203 RAX: 0000000000000000 RBX: 1ffff92000b65ec2 RCX: ffffffff815b8198 RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffffff8d6e81d0 RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffff8d6e81d7 R10: fffffbfff1add03a R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: ffff88803da400a0 R15: 0000000000000000 FS: 00007f33f887e700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2e02b000 CR3: 0000000027332000 CR4: 00000000001526e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: trace_lock_acquire include/trace/events/lock.h:13 [inline] lock_acquire+0x442/0x510 kernel/locking/lockdep.c:5596 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline] _raw_spin_lock_bh+0x2f/0x40 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:373 [inline] lock_sock_fast+0x5d/0x100 net/core/sock.c:3232 mptcp_subflow_cleanup_rbuf net/mptcp/protocol.c:465 [inline] mptcp_cleanup_rbuf net/mptcp/protocol.c:499 [inline] mptcp_recvmsg+0xad3/0x27b0 net/mptcp/protocol.c:2027 inet6_recvmsg+0x11b/0x5e0 net/ipv6/af_inet6.c:659 sock_recvmsg_nosec net/socket.c:944 [inline] ____sys_recvmsg+0x527/0x600 net/socket.c:2626 ___sys_recvmsg+0x127/0x200 net/socket.c:2670 do_recvmmsg+0x24d/0x6d0 net/socket.c:2764 __sys_recvmmsg net/socket.c:2843 [inline] __do_sys_recvmmsg net/socket.c:2866 [inline] __se_sys_recvmmsg net/socket.c:2859 [inline] __x64_sys_recvmmsg+0x20b/0x260 net/socket.c:2859 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f33fb307739 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:00007f33f887e188 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007f33fb40bf80 RCX: 00007f33fb307739 RDX: 0000000000000002 RSI: 00000000200017c0 RDI: 0000000000000005 RBP: 00007f33fb361cc4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000100 R11: 0000000000000246 R12: 00007f33fb40bf80 R13: 00007ffe315557af R14: 00007f33f887e300 R15: 0000000000022000 NMI backtrace for cpu 0 CPU: 0 PID: 21751 Comm: syz-executor.3 Not tainted 5.15.0-rc2-next-20210920-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1ae/0x220 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x25e/0x3f0 kernel/rcu/tree_stall.h:343 print_cpu_stall kernel/rcu/tree_stall.h:627 [inline] check_cpu_stall kernel/rcu/tree_stall.h:711 [inline] rcu_pending kernel/rcu/tree.c:3878 [inline] rcu_sched_clock_irq.cold+0x9d/0x746 kernel/rcu/tree.c:2597 update_process_times+0x16d/0x200 kernel/time/timer.c:1785 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:226 tick_sched_timer+0x1b0/0x2d0 kernel/time/tick-sched.c:1428 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x1c0/0xe50 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:check_kcov_mode kernel/kcov.c:163 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x7/0x60 kernel/kcov.c:197 Code: fd ff ff b9 ff ff ff ff ba 08 00 00 00 4d 8b 03 48 0f bd ca 49 8b 45 00 48 63 c9 e9 64 ff ff ff 0f 1f 00 65 8b 05 a9 ce 8b 7e <89> c1 48 8b 34 24 81 e1 00 01 00 00 65 48 8b 14 25 40 f0 01 00 a9 RSP: 0018:ffffc90005aff700 EFLAGS: 00000246 RAX: 0000000000000201 RBX: 0000000000000001 RCX: ffffc90010327000 RDX: 1ffff1100729eb26 RSI: ffffffff879f2629 RDI: ffff8880394f5780 RBP: ffff8880394f5780 R08: 0000000000000000 R09: 0000000000000001 R10: ffffffff88e98f45 R11: 0000000000000000 R12: ffff8880394f5930 R13: ffff8880394f5930 R14: dffffc0000000000 R15: 0000000000000001 inet_csk_ack_scheduled include/net/inet_connection_sock.h:182 [inline] tcp_cleanup_rbuf+0x124/0x5a0 net/ipv4/tcp.c:1558 mptcp_subflow_cleanup_rbuf net/mptcp/protocol.c:467 [inline] mptcp_cleanup_rbuf net/mptcp/protocol.c:499 [inline] mptcp_recvmsg+0xcf6/0x27b0 net/mptcp/protocol.c:2027 inet6_recvmsg+0x11b/0x5e0 net/ipv6/af_inet6.c:659 sock_recvmsg_nosec net/socket.c:944 [inline] ____sys_recvmsg+0x527/0x600 net/socket.c:2626 ___sys_recvmsg+0x127/0x200 net/socket.c:2670 do_recvmmsg+0x24d/0x6d0 net/socket.c:2764 __sys_recvmmsg net/socket.c:2843 [inline] __do_sys_recvmmsg net/socket.c:2866 [inline] __se_sys_recvmmsg net/socket.c:2859 [inline] __x64_sys_recvmmsg+0x20b/0x260 net/socket.c:2859 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7fac34ad8739 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:00007fac3200d188 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007fac34bdd0f0 RCX: 00007fac34ad8739 RDX: 0000000000000002 RSI: 00000000200017c0 RDI: 0000000000000005 RBP: 00007fac34b32cc4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000100 R11: 0000000000000246 R12: 00007fac34bdd0f0 R13: 00007ffda532eedf R14: 00007fac3200d300 R15: 0000000000022000 ---------------- Code disassembly (best guess): 0: 49 c1 ec 09 shr $0x9,%r12 4: 49 83 f4 01 xor $0x1,%r12 8: 41 83 e4 01 and $0x1,%r12d c: 44 89 e0 mov %r12d,%eax f: 41 5c pop %r12 11: c3 retq 12: 45 31 e4 xor %r12d,%r12d 15: 44 89 e0 mov %r12d,%eax 18: 41 5c pop %r12 1a: c3 retq 1b: 66 66 2e 0f 1f 84 00 data16 nopw %cs:0x0(%rax,%rax,1) 22: 00 00 00 00 26: 66 90 xchg %ax,%ax 28: 41 54 push %r12 * 2a: 41 bc 01 00 00 00 mov $0x1,%r12d <-- trapping instruction 30: e8 f3 83 d1 07 callq 0x7d18428 35: 85 c0 test %eax,%eax 37: 75 06 jne 0x3f 39: 44 89 e0 mov %r12d,%eax 3c: 41 5c pop %r12 3e: c3 retq 3f: e8 .byte 0xe8