rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P21178/1:b..l rcu: (detected by 0, t=10502 jiffies, g=148109, q=162 ncpus=2) task:syz.0.2954 state:R running task stack:25640 pid:21178 ppid:12507 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5380 [inline] __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699 preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7009 irqentry_exit+0x67/0x70 kernel/entry/common.c:438 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:__kasan_check_read+0x4/0x20 mm/kasan/shadow.c:31 Code: 41 5e 41 5f 5d c3 48 c7 c7 7e 1c 79 8c 4c 89 e6 eb 0a 48 c7 c7 3b 76 61 8c 48 89 de e8 35 27 85 08 31 ed eb d4 cc f3 0f 1e fa <89> f6 48 8b 0c 24 31 d2 e9 df ea ff ff 66 2e 0f 1f 84 00 00 00 00 RSP: 0018:ffffc900046af778 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000002 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8e4a8828 RBP: ffffc900046af898 R08: 0000000000000000 R09: 0000000000000000 R10: ffffc900046afa4c R11: fffff520008d5f52 R12: 1ffff920008d5efc R13: ffffffff8cd2fbe0 R14: 0000000000000001 R15: dffffc0000000000 instrument_atomic_read include/linux/instrumented.h:68 [inline] _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline] cpumask_test_cpu include/linux/cpumask.h:504 [inline] cpu_online include/linux/cpumask.h:1082 [inline] trace_lock_acquire include/trace/events/lock.h:24 [inline] lock_acquire+0xbc/0x410 kernel/locking/lockdep.c:5725 rcu_lock_acquire include/linux/rcupdate.h:334 [inline] rcu_read_lock include/linux/rcupdate.h:786 [inline] __pte_offset_map+0x48/0x2c0 mm/pgtable-generic.c:287 pte_offset_map_nolock+0x44/0x130 mm/pgtable-generic.c:314 handle_pte_fault mm/memory.c:5011 [inline] __handle_mm_fault mm/memory.c:5166 [inline] handle_mm_fault+0xe1b/0x4920 mm/memory.c:5331 faultin_page mm/gup.c:868 [inline] __get_user_pages+0x5ea/0x1470 mm/gup.c:1167 populate_vma_page_range+0x2b6/0x370 mm/gup.c:1593 __mm_populate+0x24c/0x380 mm/gup.c:1696 mm_populate include/linux/mm.h:3317 [inline] vm_mmap_pgoff+0x2e7/0x400 mm/util.c:561 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fe74bf8ebe9 RSP: 002b:00007fe74ce83038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007fe74c1b5fa0 RCX: 00007fe74bf8ebe9 RDX: b635773f06ebbeef RSI: 0000000000b36000 RDI: 0000200000000000 RBP: 00007fe74c011e19 R08: ffffffffffffffff R09: 0000000000000000 R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fe74c1b6038 R14: 00007fe74c1b5fa0 R15: 00007fffe4b0a548 rcu: rcu_preempt kthread starved for 10408 jiffies! g148109 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:27080 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5380 [inline] __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699 schedule+0xbd/0x170 kernel/sched/core.c:6773 schedule_timeout+0x160/0x280 kernel/time/timer.c:2167 rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667 rcu_gp_kthread+0x99/0x380 kernel/rcu/tree.c:1866 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 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: 0 Comm: swapper/1 Not tainted 6.6.102-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:148 Code: cc cc cc cc cc cc cc f3 0f 1e fa 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 66 90 0f 00 2d e3 e6 3a 00 f3 0f 1e fa fb f4 cc cc cc cc cc cc cc cc cc cc cc cc 66 0f 1f 00 55 41 57 41 56 RSP: 0018:ffffc90000187de0 EFLAGS: 000002c6 RAX: fc7f862d8c648300 RBX: ffffffff8161914b RCX: fc7f862d8c648300 RDX: 0000000000000001 RSI: ffffffff8aaab9c0 RDI: ffffffff8afc66c0 RBP: ffffc90000187f20 R08: ffff8880b8f36d4b R09: 1ffff110171e6da9 R10: dffffc0000000000 R11: ffffed10171e6daa R12: ffffffff8e4a8828 R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff110037cb780 FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f3478b4ff98 CR3: 000000002d69d000 CR4: 00000000003506e0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:753 default_idle_call+0x6c/0xa0 kernel/sched/idle.c:97 cpuidle_idle_call kernel/sched/idle.c:170 [inline] do_idle+0x1eb/0x510 kernel/sched/idle.c:282 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:380 start_secondary+0xee/0xf0 arch/x86/kernel/smpboot.c:323 secondary_startup_64_no_verify+0x179/0x17b