rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6642/1:b..l rcu: (detected by 1, t=10503 jiffies, g=11333, q=1693 ncpus=2) task:syz.4.218 state:R running task stack:25512 pid:6642 tgid:6642 ppid:5810 task_flags:0x400040 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5396 [inline] __schedule+0x116a/0x5de0 kernel/sched/core.c:6785 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7108 irqentry_exit+0x36/0x90 kernel/entry/common.c:307 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_acquire+0x62/0x350 kernel/locking/lockdep.c:5875 Code: 63 34 12 83 f8 07 0f 87 bc 02 00 00 89 c0 48 0f a3 05 62 96 0f 0f 0f 82 74 02 00 00 8b 35 4a c8 0f 0f 85 f6 0f 85 8d 00 00 00 <48> 8b 44 24 30 65 48 2b 05 f9 62 34 12 0f 85 c7 02 00 00 48 83 c4 RSP: 0018:ffffc9000ba07170 EFLAGS: 00000206 RAX: 0000000000000046 RBX: ffffffff8e5c4940 RCX: 00000000d2211cd3 RDX: 0000000000000000 RSI: ffffffff8ddf4bc3 RDI: ffffffff8c157ba0 RBP: 0000000000000002 R08: df5c6cda94746d70 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:841 [inline] page_ext_get+0x36/0x1a0 mm/page_ext.c:538 __reset_page_owner+0x2b/0x1a0 mm/page_owner.c:294 reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1248 [inline] __free_frozen_pages+0x7fe/0x1180 mm/page_alloc.c:2706 discard_slab mm/slub.c:2717 [inline] __put_partials+0x16d/0x1c0 mm/slub.c:3186 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x4d/0x120 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:329 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4148 [inline] slab_alloc_node mm/slub.c:4197 [inline] kmem_cache_alloc_noprof+0x1cb/0x3b0 mm/slub.c:4204 mt_alloc_one lib/maple_tree.c:176 [inline] mas_alloc_nodes+0x18b/0x8b0 lib/maple_tree.c:1249 mas_node_count_gfp+0x105/0x130 lib/maple_tree.c:1331 mas_preallocate+0x7e0/0xde0 lib/maple_tree.c:5533 vma_iter_prealloc mm/vma.h:463 [inline] __split_vma+0x34a/0x1070 mm/vma.c:525 vms_gather_munmap_vmas+0x392/0x1310 mm/vma.c:1375 __mmap_prepare mm/vma.c:2351 [inline] __mmap_region+0x3c7/0x25e0 mm/vma.c:2607 mmap_region+0x32b/0x3f0 mm/vma.c:2692 do_mmap+0xa3e/0x1210 mm/mmap.c:561 vm_mmap_pgoff+0x281/0x450 mm/util.c:579 ksys_mmap_pgoff+0x32c/0x5c0 mm/mmap.c:607 __do_sys_mmap arch/x86/kernel/sys_x86_64.c:89 [inline] __se_sys_mmap arch/x86/kernel/sys_x86_64.c:82 [inline] __x64_sys_mmap+0x125/0x190 arch/x86/kernel/sys_x86_64.c:82 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fea6b98e963 RSP: 002b:00007ffe285e41f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007fea6bbb63b8 RCX: 00007fea6b98e963 RDX: 0000000000000003 RSI: 0000000000400000 RDI: 00007fea68ff4000 RBP: 00007fea6bbb6320 R08: 00000000000000dc R09: 0000000000000000 R10: 0000000000000011 R11: 0000000000000246 R12: 00007fea6bbb5fa0 R13: 00007fea6bbb6320 R14: 0000000000001275 R15: 0000000000000004 rcu: rcu_preempt kthread starved for 6354 jiffies! g11333 f0x0 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:27784 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5396 [inline] __schedule+0x116a/0x5de0 kernel/sched/core.c:6785 __schedule_loop kernel/sched/core.c:6863 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6878 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2054 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2256 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.16.0-rc3-syzkaller-00116-ge34a79b96ab9 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82 Code: eb 71 02 e9 03 fb 02 00 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 63 70 29 00 fb f4 cc cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffffff8e207e08 EFLAGS: 000002c2 RAX: 00000000019eb81b RBX: 0000000000000000 RCX: ffffffff8b809c59 RDX: 0000000000000000 RSI: ffffffff8de1a086 RDI: ffffffff8c157ba0 RBP: fffffbfff1c52ef0 R08: 0000000000000001 R09: ffffed1017086645 R10: ffff8880b843322b R11: 0000000000000001 R12: 0000000000000000 R13: ffffffff8e297780 R14: ffffffff90a81350 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888124752000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff6d812ba90 CR3: 0000000078773000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:749 default_idle_call+0x6d/0xb0 kernel/sched/idle.c:117 cpuidle_idle_call kernel/sched/idle.c:185 [inline] do_idle+0x391/0x510 kernel/sched/idle.c:325 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:423 rest_init+0x16b/0x2b0 init/main.c:745 start_kernel+0x3ee/0x4d0 init/main.c:1102 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:307 x86_64_start_kernel+0x130/0x190 arch/x86/kernel/head64.c:288 common_startup_64+0x13e/0x148