rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (10499 ticks this GP) idle=ac7/1/0x4000000000000000 softirq=10706/10706 fqs=21 (t=10500 jiffies g=12925 q=5835) rcu: rcu_preempt kthread starved for 10407 jiffies! g12925 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:29400 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: 8952 Comm: syz-executor783 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:__kasan_check_read+0x0/0x10 mm/kasan/shadow.c:31 Code: 8b e8 98 b8 34 07 48 85 db 0f 85 c3 12 36 07 48 83 c4 60 5b 5d 41 5c 41 5d c3 c3 e9 c3 13 36 07 cc cc cc cc cc cc cc cc cc cc <48> 8b 0c 24 89 f6 31 d2 e9 f3 f9 ff ff 0f 1f 00 48 8b 0c 24 89 f6 RSP: 0018:ffffc9000cf97730 EFLAGS: 00000246 RAX: 0000000000000011 RBX: ffff88807cd15700 RCX: ffffffff88e99454 RDX: ffffed1003ae1287 RSI: 0000000000000008 RDI: ffff88801d708c20 RBP: ffff88801d709430 R08: 0000000000000000 R09: ffff88801d709437 R10: ffffed1003ae1286 R11: 0000000000000000 R12: ffff88801d708c20 R13: ffffc9000cf97828 R14: dffffc0000000000 R15: ffff88801d708bc0 FS: 0000555556d3d300(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020000180 CR3: 0000000067999000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: instrument_atomic_read include/linux/instrumented.h:71 [inline] test_bit include/asm-generic/bitops/instrumented-non-atomic.h:134 [inline] sock_flag include/net/sock.h:904 [inline] sk_clear_bit include/net/sock.h:2326 [inline] mptcp_wait_data net/mptcp/protocol.c:1773 [inline] mptcp_recvmsg+0x107a/0x27b0 net/mptcp/protocol.c:2080 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: 0033:0x7ff198670c39 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 41 15 00 00 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 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffe47998038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007ff198670c39 RDX: 0000000000000002 RSI: 00000000200017c0 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000f0b5ff R10: 0000000000000100 R11: 0000000000000246 R12: 0000000000055529 R13: 00007ffe47998060 R14: 00007ffe47998050 R15: 00007ffe47998044 INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.369 msecs NMI backtrace for cpu 0 CPU: 0 PID: 8946 Comm: syz-executor783 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:__local_bh_enable_ip+0xa8/0x120 kernel/softirq.c:390 Code: 1d 9d 8c bb 7e 65 8b 05 96 8c bb 7e a9 00 ff ff 00 74 45 bf 01 00 00 00 e8 a5 31 09 00 e8 00 e9 35 00 fb 65 8b 05 78 8c bb 7e <85> c0 74 58 5b 5d c3 65 8b 05 c6 93 bb 7e 85 c0 75 a2 0f 0b eb 9e RSP: 0018:ffffc9000cfa7720 EFLAGS: 00000202 RAX: 0000000000000000 RBX: 00000000fffffe00 RCX: 1ffffffff1faa266 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffffff88e98f8b R08: 0000000000000001 R09: ffffffff8fd06a07 R10: 0000000000000001 R11: 0000000000000442 R12: 0000000000000000 R13: 0000000000000001 R14: dffffc0000000000 R15: 0000000000000001 spin_unlock_bh include/linux/spinlock.h:413 [inline] unlock_sock_fast include/net/sock.h:1644 [inline] unlock_sock_fast include/net/sock.h:1636 [inline] mptcp_subflow_cleanup_rbuf net/mptcp/protocol.c:468 [inline] mptcp_cleanup_rbuf net/mptcp/protocol.c:499 [inline] mptcp_recvmsg+0xb8b/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: 0033:0x7ff198670c39 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 41 15 00 00 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 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffe47998038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007ff198670c39 RDX: 0000000000000002 RSI: 00000000200017c0 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000900f0b5ff R10: 0000000000000100 R11: 0000000000000246 R12: 000000000005403b R13: 00007ffe47998060 R14: 00007ffe47998050 R15: 00007ffe47998044 ---------------- Code disassembly (best guess), 1 bytes skipped: 0: e8 98 b8 34 07 callq 0x734b89d 5: 48 85 db test %rbx,%rbx 8: 0f 85 c3 12 36 07 jne 0x73612d1 e: 48 83 c4 60 add $0x60,%rsp 12: 5b pop %rbx 13: 5d pop %rbp 14: 41 5c pop %r12 16: 41 5d pop %r13 18: c3 retq 19: c3 retq 1a: e9 c3 13 36 07 jmpq 0x73613e2 1f: cc int3 20: cc int3 21: cc int3 22: cc int3 23: cc int3 24: cc int3 25: cc int3 26: cc int3 27: cc int3 28: cc int3 * 29: 48 8b 0c 24 mov (%rsp),%rcx <-- trapping instruction 2d: 89 f6 mov %esi,%esi 2f: 31 d2 xor %edx,%edx 31: e9 f3 f9 ff ff jmpq 0xfffffa29 36: 0f 1f 00 nopl (%rax) 39: 48 8b 0c 24 mov (%rsp),%rcx 3d: 89 f6 mov %esi,%esi