rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 1, t=10502 jiffies, g=31133, q=8) rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4294968255-4294957753), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10502 jiffies! g31133 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: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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 11592 Comm: syz-executor.4 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+0x4/0x10 mm/kasan/shadow.c:31 Code: 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 ba 01 00 00 RSP: 0018:ffffc90000007fd0 EFLAGS: 00000046 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff81316953 RDX: ffff88807864d700 RSI: 0000000000000008 RDI: ffffffff8d6e81d0 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff8165f049 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f5925c2c700(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2ea2e000 CR3: 0000000044d1c000 CR4: 00000000001506f0 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] cpumask_test_cpu include/linux/cpumask.h:344 [inline] cpu_online include/linux/cpumask.h:895 [inline] trace_local_timer_exit arch/x86/include/asm/trace/irq_vectors.h:41 [inline] __sysvec_apic_timer_interrupt+0x173/0x530 arch/x86/kernel/apic/apic.c:1104 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:__sanitizer_cov_trace_const_cmp1+0x1/0x80 kernel/kcov.c:269 Code: fe 72 1f 48 83 c2 01 4c 89 44 38 e8 48 c7 44 38 e0 06 00 00 00 48 89 4c 38 f0 4e 89 54 c8 20 48 89 10 c3 66 0f 1f 44 00 00 53 <41> 89 fb 41 89 f1 bf 03 00 00 00 65 48 8b 0c 25 40 f0 01 00 48 89 RSP: 0018:ffffc9000484f728 EFLAGS: 00000202 RAX: 00000000fffffd99 RBX: ffff888072254a00 RCX: 0000000000000001 RDX: 0000000000040000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffff88806dca2580 R08: 0000000000000000 R09: 0000000000000001 R10: ffffffff88e98f19 R11: 000000000000001f R12: 0000000000000000 R13: 0000000000000001 R14: dffffc0000000000 R15: 0000000000000001 mptcp_subflow_cleanup_rbuf net/mptcp/protocol.c:466 [inline] mptcp_cleanup_rbuf net/mptcp/protocol.c:499 [inline] mptcp_recvmsg+0xb45/0x27b0 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: 0033:0x7f59286b5739 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:00007f5925c2c188 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007f59287b9f80 RCX: 00007f59286b5739 RDX: 0000000000000002 RSI: 00000000200017c0 RDI: 0000000000000005 RBP: 00007f592870fcc4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000100 R11: 0000000000000246 R12: 00007f59287b9f80 R13: 00007fff6669711f R14: 00007f5925c2c300 R15: 0000000000022000 ---------------- Code disassembly (best guess): 0: 34 07 xor $0x7,%al 2: 48 85 db test %rbx,%rbx 5: 0f 85 c3 12 36 07 jne 0x73612ce b: 48 83 c4 60 add $0x60,%rsp f: 5b pop %rbx 10: 5d pop %rbp 11: 41 5c pop %r12 13: 41 5d pop %r13 15: c3 retq 16: c3 retq 17: e9 c3 13 36 07 jmpq 0x73613df 1c: cc int3 1d: cc int3 1e: cc int3 1f: cc int3 20: cc int3 21: cc int3 22: cc int3 23: cc int3 24: cc int3 25: cc int3 26: 48 8b 0c 24 mov (%rsp),%rcx * 2a: 89 f6 mov %esi,%esi <-- trapping instruction 2c: 31 d2 xor %edx,%edx 2e: e9 f3 f9 ff ff jmpq 0xfffffa26 33: 0f 1f 00 nopl (%rax) 36: 48 8b 0c 24 mov (%rsp),%rcx 3a: 89 f6 mov %esi,%esi 3c: ba .byte 0xba 3d: 01 00 add %eax,(%rax)