rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4809/1:b..l (detected by 0, t=10502 jiffies, g=11713, q=204 ncpus=2) task:rm state:R running task stack:24352 pid:4809 ppid:4778 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6873 irqentry_exit+0x63/0x70 kernel/entry/common.c:439 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:lock_is_held_type+0x7/0x190 kernel/locking/lockdep.c:5690 Code: c7 c7 a0 01 8c 8a 48 c7 c6 e0 01 8c 8a e8 e1 b5 35 f7 0f 0b eb bf e8 98 fd ff ff 0f 1f 84 00 00 00 00 00 55 41 57 41 56 41 55 <41> 54 53 48 83 ec 10 65 48 8b 04 25 28 00 00 00 48 89 44 24 08 bd RSP: 0018:ffffc9000491f858 EFLAGS: 00000246 RAX: 1ffff1100ef3df00 RBX: 0000000000000000 RCX: dffffc0000000000 RDX: 0000000000000000 RSI: 00000000ffffffff RDI: ffff8880779ef958 RBP: ffffc9000491fa50 R08: ffff888074028000 R09: 0000000000000003 R10: 0000000000000003 R11: 0000000000000000 R12: ffff888076636948 R13: ffff88801df7b080 R14: ffff8880779ef958 R15: 0000000000000300 lock_is_held include/linux/lockdep.h:283 [inline] mt_locked lib/maple_tree.c:-1 [inline] mt_slot lib/maple_tree.c:814 [inline] mas_slot lib/maple_tree.c:847 [inline] mt_validate_nulls lib/maple_tree.c:7191 [inline] mt_validate+0x43ce/0x4c90 lib/maple_tree.c:7247 validate_mm_mt+0xcd/0x420 mm/mmap.c:295 validate_mm+0xcc/0x2b0 mm/mmap.c:332 do_mmap+0xc7/0xfd0 mm/mmap.c:1270 vm_mmap_pgoff+0x1b2/0x2b0 mm/util.c:520 ksys_mmap_pgoff+0x516/0x6f0 mm/mmap.c:1482 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7ff14f47b242 RSP: 002b:00007ffcc143e288 EFLAGS: 00000206 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007ff14f1af000 RCX: 00007ff14f47b242 RDX: 0000000000000001 RSI: 0000000000004000 RDI: 00007ff14f1af000 RBP: 0000000000000812 R08: 0000000000000003 R09: 000000000000b000 R10: 0000000000000812 R11: 0000000000000206 R12: 00007ffcc143e310 R13: 00007ff14f457b20 R14: 00007ffcc143e6c0 R15: 00000fff98287c54 rcu: rcu_preempt kthread starved for 10409 jiffies! g11713 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:27840 pid:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561 schedule+0xb9/0x180 kernel/sched/core.c:6637 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1965 rcu_gp_fqs_loop+0x2f2/0x1310 kernel/rcu/tree.c:1706 rcu_gp_kthread+0x95/0x380 kernel/rcu/tree.c:1905 kthread+0x29d/0x330 kernel/kthread.c:376 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: 4763 Comm: syz.4.81 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:check_preemption_disabled+0x6/0x110 lib/smp_processor_id.c:13 Code: 89 f6 e8 bd 32 17 fa e9 6e ff ff ff 00 00 cc cc 00 00 cc cc 48 c7 c7 80 fa de 8a 48 c7 c6 c0 fa de 8a eb 00 55 41 57 41 56 53 <48> 83 ec 10 65 48 8b 04 25 28 00 00 00 48 89 44 24 08 65 8b 05 21 RSP: 0018:ffffc900034a78b8 EFLAGS: 00000046 RAX: 0000000000000046 RBX: ffff888027210adc RCX: f2701722961c0100 RDX: 0000000000000000 RSI: ffffffff8a8c0fe0 RDI: ffffffff8adefae0 RBP: ffffc900034a79f0 R08: dffffc0000000000 R09: fffffbfff1c3ee26 R10: fffffbfff1c3ee26 R11: 1ffffffff1c3ee25 R12: 0000000000000000 R13: dffffc0000000000 R14: ffff888027210000 R15: 1ffff92000694f28 FS: 00007fac504a16c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c33a3e6 CR3: 000000002d50d000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lockdep_recursion_inc kernel/locking/lockdep.c:462 [inline] lock_release+0x16f/0x910 kernel/locking/lockdep.c:5681 seqcount_lockdep_reader_access+0xd9/0x1c0 include/linux/seqlock.h:103 timekeeping_get_delta kernel/time/timekeeping.c:254 [inline] timekeeping_get_ns kernel/time/timekeeping.c:388 [inline] ktime_get+0x7b/0x270 kernel/time/timekeeping.c:848 common_hrtimer_rearm+0x5d/0x110 kernel/time/posix-timers.c:303 posixtimer_rearm+0x131/0x340 kernel/time/posix-timers.c:329 dequeue_signal+0x1b6/0x4b0 kernel/signal.c:704 get_signal+0x547/0x1350 kernel/signal.c:2751 arch_do_signal_or_restart+0xb0/0x1230 arch/x86/kernel/signal.c:871 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fac4f58ebe9 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fac504a10e8 EFLAGS: 00000246 RAX: fffffffffffffffc RBX: 00007fac4f7c5fa8 RCX: 00007fac4f58ebe9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fac4f7c5fa8 RBP: 00007fac4f7c5fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fac4f7c6038 R14: 00007ffd14ec7ad0 R15: 00007ffd14ec7bb8