rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6818/1:b..l (detected by 0, t=10502 jiffies, g=376893, q=17100) task:syz-executor.3 state:R running task stack:23752 pid: 6818 ppid: 1 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:4972 [inline] __schedule+0xa9a/0x4940 kernel/sched/core.c:6253 preempt_schedule_common+0x45/0xc0 kernel/sched/core.c:6419 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:35 __raw_read_unlock include/linux/rwlock_api_smp.h:225 [inline] _raw_read_unlock+0x36/0x40 kernel/locking/spinlock.c:260 zap_pid_ns_processes+0x271/0x660 kernel/pid_namespace.c:207 find_child_reaper kernel/exit.c:548 [inline] forget_original_parent kernel/exit.c:637 [inline] exit_notify kernel/exit.c:674 [inline] do_exit+0x243d/0x2b40 kernel/exit.c:852 do_group_exit+0x125/0x310 kernel/exit.c:929 get_signal+0x47d/0x2220 kernel/signal.c:2852 arch_do_signal_or_restart+0x2a9/0x1c40 arch/x86/kernel/signal.c:868 handle_signal_work kernel/entry/common.c:148 [inline] exit_to_user_mode_loop kernel/entry/common.c:172 [inline] exit_to_user_mode_prepare+0x17d/0x290 kernel/entry/common.c:207 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline] syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:300 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f271920f811 RSP: 002b:00007f2719831d10 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6 RAX: 0000000000000000 RBX: 0000000000002348 RCX: 00007f271920f811 RDX: 00007f2719831d50 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f2719831ddc R08: 0000000000000000 R09: 00007ffd28edd080 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000047 R13: 00000000002600dc R14: 0000000000000009 R15: 00007f2719831e40 rcu: rcu_preempt kthread timer wakeup didn't happen for 2097 jiffies! g376893 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=156315 rcu: rcu_preempt kthread starved for 2098 jiffies! g376893 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:28688 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4972 [inline] __schedule+0xa9a/0x4940 kernel/sched/core.c:6253 schedule+0xd2/0x260 kernel/sched/core.c:6326 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: 8401 Comm: syz-executor.5 Not tainted 5.16.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:rb_add_cached include/linux/rbtree.h:172 [inline] RIP: 0010:timerqueue_add+0xd2/0x330 lib/timerqueue.c:40 Code: 01 00 00 00 49 bc 00 00 00 00 00 fc ff df eb 2b e8 73 a7 77 fd 4c 8d 7b 10 e8 6a a7 77 fd 4c 89 fa 48 c1 ea 03 42 80 3c 22 00 <0f> 85 c4 01 00 00 49 8b 17 48 85 d2 74 40 48 89 d3 e8 48 a7 77 fd RSP: 0018:ffffc90000dc0dd0 EFLAGS: 00000046 RAX: 0000000080010001 RBX: ffff8880b9d2ade0 RCX: 0000000000000000 RDX: 1ffff110173a55be RSI: ffffffff84000356 RDI: 0000000000000003 RBP: ffff88816ef73648 R08: 0000027875346b95 R09: 0000000000000000 R10: ffffffff8400039d R11: 0000000000000000 R12: dffffc0000000000 R13: 0000027875346b95 R14: 0000000000000001 R15: ffff8880b9d2adf0 FS: 0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c004e4f018 CR3: 000000006fbe6000 CR4: 00000000003526e0 Call Trace: enqueue_hrtimer+0x176/0x3e0 kernel/time/hrtimer.c:1091 __run_hrtimer kernel/time/hrtimer.c:1702 [inline] __hrtimer_run_queues+0xb02/0xe50 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:_compound_head include/linux/page-flags.h:200 [inline] RIP: 0010:PageSwapCache include/linux/page-flags.h:493 [inline] RIP: 0010:free_swap_cache+0x31/0x200 mm/swap_state.c:291 Code: fd 53 4c 8d 6d 08 e8 6e 16 c1 ff 4c 89 ea 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 0f 85 96 01 00 00 4c 8b 65 08 <31> ff 4c 89 e3 83 e3 01 48 89 de e8 cf 18 c1 ff 48 85 db 0f 85 60 RSP: 0018:ffffc90004f27700 EFLAGS: 00000246 RAX: dffffc0000000000 RBX: ffff8880234a16a0 RCX: 0000000000000000 RDX: 1ffffd400038bb31 RSI: ffffffff81b69452 RDI: ffffea0001c5d980 RBP: ffffea0001c5d980 R08: 00000000000001fe R09: 0000000000000000 R10: ffffffff81b69912 R11: 0000000000000000 R12: 0000000000000000 R13: ffffea0001c5d988 R14: dffffc0000000000 R15: ffffc90004f27aa8 free_pages_and_swap_cache+0x58/0x90 mm/swap_state.c:319 tlb_batch_pages_flush mm/mmu_gather.c:49 [inline] tlb_flush_mmu_free mm/mmu_gather.c:242 [inline] tlb_flush_mmu+0xe9/0x6b0 mm/mmu_gather.c:249 zap_pte_range mm/memory.c:1418 [inline] zap_pmd_range mm/memory.c:1467 [inline] zap_pud_range mm/memory.c:1496 [inline] zap_p4d_range mm/memory.c:1517 [inline] unmap_page_range+0x1cac/0x29f0 mm/memory.c:1538 unmap_single_vma+0x198/0x310 mm/memory.c:1583 unmap_vmas+0x16b/0x2f0 mm/memory.c:1615 exit_mmap+0x1d0/0x630 mm/mmap.c:3170 __mmput+0x122/0x4b0 kernel/fork.c:1113 mmput+0x56/0x60 kernel/fork.c:1134 exit_mm kernel/exit.c:507 [inline] do_exit+0xb27/0x2b40 kernel/exit.c:819 do_group_exit+0x125/0x310 kernel/exit.c:929 get_signal+0x47d/0x2220 kernel/signal.c:2852 arch_do_signal_or_restart+0x2a9/0x1c40 arch/x86/kernel/signal.c:868 handle_signal_work kernel/entry/common.c:148 [inline] exit_to_user_mode_loop kernel/entry/common.c:172 [inline] exit_to_user_mode_prepare+0x17d/0x290 kernel/entry/common.c:207 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline] syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:300 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7fd97c84aae9 Code: Unable to access opcode bytes at RIP 0x7fd97c84aabf. RSP: 002b:00007fd979dc0218 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007fd97c95df68 RCX: 00007fd97c84aae9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fd97c95df68 RBP: 00007fd97c95df60 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fd97c95df6c R13: 00007fd97ce91b2f R14: 00007fd979dc0300 R15: 0000000000022000 ---------------- Code disassembly (best guess): 0: 01 00 add %eax,(%rax) 2: 00 00 add %al,(%rax) 4: 49 bc 00 00 00 00 00 movabs $0xdffffc0000000000,%r12 b: fc ff df e: eb 2b jmp 0x3b 10: e8 73 a7 77 fd callq 0xfd77a788 15: 4c 8d 7b 10 lea 0x10(%rbx),%r15 19: e8 6a a7 77 fd callq 0xfd77a788 1e: 4c 89 fa mov %r15,%rdx 21: 48 c1 ea 03 shr $0x3,%rdx 25: 42 80 3c 22 00 cmpb $0x0,(%rdx,%r12,1) * 2a: 0f 85 c4 01 00 00 jne 0x1f4 <-- trapping instruction 30: 49 8b 17 mov (%r15),%rdx 33: 48 85 d2 test %rdx,%rdx 36: 74 40 je 0x78 38: 48 89 d3 mov %rdx,%rbx 3b: e8 48 a7 77 fd callq 0xfd77a788