rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P12248/1:b..l P12414/2:b..l rcu: (detected by 1, t=10503 jiffies, g=74261, q=564 ncpus=2) task:syz.0.1240 state:R running task stack:26488 pid:12414 tgid:12406 ppid:11634 task_flags:0x400040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x14ed/0x5040 kernel/sched/core.c:6866 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7193 irqentry_exit+0x5e3/0x670 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_is_held_type+0x107/0x150 kernel/locking/lockdep.c:5945 Code: 18 00 00 b8 ff ff ff ff 65 0f c1 05 a3 c0 44 07 83 f8 01 75 25 9c 58 a9 00 02 00 00 75 39 41 f7 c4 00 02 00 00 74 01 fb 89 d8 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 90 0f 0b 90 48 c7 RSP: 0018:ffffc9000b5b73e8 EFLAGS: 00000206 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000046 RDX: ffff88802554bc80 RSI: ffffffff8db80e95 RDI: ffffffff8be082e0 RBP: 00000000ffffffff R08: ffff88802554bc80 R09: 0000000000000002 R10: 0000000000000003 R11: 0000000000000002 R12: 0000000000000246 R13: ffff88802554bc80 R14: ffff8880515cb780 R15: 0000000000000003 lock_is_held include/linux/lockdep.h:249 [inline] xa_head include/linux/xarray.h:1211 [inline] xas_start+0x1e8/0x770 lib/xarray.c:191 xas_load+0x2c/0x5b0 lib/xarray.c:239 xas_find+0x157/0x990 lib/xarray.c:1406 next_uptodate_folio+0x32/0x5d0 mm/filemap.c:3699 filemap_map_pages+0x222/0x1fd0 mm/filemap.c:3882 do_fault_around mm/memory.c:5695 [inline] do_read_fault mm/memory.c:5728 [inline] do_fault mm/memory.c:5871 [inline] do_pte_missing+0x20b0/0x3330 mm/memory.c:4416 handle_pte_fault mm/memory.c:6255 [inline] __handle_mm_fault mm/memory.c:6393 [inline] handle_mm_fault+0x1b26/0x32b0 mm/memory.c:6562 faultin_page mm/gup.c:1126 [inline] __get_user_pages+0x1650/0x29f0 mm/gup.c:1428 populate_vma_page_range+0x29f/0x3a0 mm/gup.c:1860 __mm_populate+0x24c/0x380 mm/gup.c:1963 mm_populate include/linux/mm.h:3701 [inline] vm_mmap_pgoff+0x387/0x4d0 mm/util.c:586 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe66698f749 RSP: 002b:00007fe6677be038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007fe666be6090 RCX: 00007fe66698f749 RDX: b635773f07ebbeeb RSI: 0000000000b36000 RDI: 0000200000000000 RBP: 00007fe666a13f91 R08: ffffffffffffffff R09: 00000000c36e5000 R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fe666be6128 R14: 00007fe666be6090 R15: 00007ffcfe42f068 task:syz.6.1215 state:R running task stack:20832 pid:12248 tgid:12248 ppid:9127 task_flags:0x400640 flags:0x00080001 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x14ed/0x5040 kernel/sched/core.c:6866 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7193 irqentry_exit+0x5e3/0x670 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:ptlock_ptr include/linux/mm.h:3236 [inline] RIP: 0010:pte_lockptr include/linux/mm.h:3260 [inline] RIP: 0010:__pte_offset_map_lock+0x128/0x210 mm/pgtable-generic.c:402 Code: e8 3d 48 ad ff 4d 21 f5 49 c1 ed 06 4b 8d 2c 2f 48 83 c5 28 48 89 e8 48 c1 e8 03 49 be 00 00 00 00 00 fc ff df 42 80 3c 30 00 <74> 08 48 89 ef e8 be 06 14 00 48 8b 6d 00 48 89 ef e8 92 dd 4b 09 RSP: 0018:ffffc9000470e8e8 EFLAGS: 00000246 RAX: 1ffffd400012bc5d RBX: ffff888073938428 RCX: ffff8880263b3c80 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffea000095e2e8 R08: ffffffff82137199 R09: ffffffff8e13f2a0 R10: dffffc0000000000 R11: ffffed1004c76791 R12: 1ffff1100e727085 R13: 000000000095e2c0 R14: dffffc0000000000 R15: ffffea0000000000 pte_offset_map_lock include/linux/mm.h:3361 [inline] follow_page_pte+0xc4/0x13e0 mm/gup.c:812 follow_pmd_mask mm/gup.c:-1 [inline] follow_pud_mask mm/gup.c:967 [inline] follow_p4d_mask mm/gup.c:984 [inline] follow_page_mask mm/gup.c:1023 [inline] __get_user_pages+0xa6c/0x29f0 mm/gup.c:1426 __get_user_pages_locked mm/gup.c:1692 [inline] get_dump_page+0x1ac/0x3f0 mm/gup.c:2192 dump_user_range+0x1de/0xc90 fs/coredump.c:1366 elf_core_dump+0x3369/0x3960 fs/binfmt_elf.c:2111 coredump_write+0x1121/0x18b0 fs/coredump.c:1049 do_coredump fs/coredump.c:1126 [inline] vfs_coredump+0x3321/0x3e60 fs/coredump.c:1200 get_signal+0x1108/0x1340 kernel/signal.c:3019 arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline] exit_to_user_mode_loop kernel/entry/common.c:75 [inline] __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:270 [inline] irqentry_exit_to_user_mode include/linux/irq-entry-common.h:339 [inline] irqentry_exit+0x178/0x670 kernel/entry/common.c:196 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0033:0x7f2dcfc4f6b7 RSP: 002b:00007f2dd0bb1120 EFLAGS: 00010202 RAX: 0000000000000000 RBX: 000000000000000b RCX: 00007f2dcfd8f749 RDX: 00007f2dd0bb1140 RSI: 00007f2dd0bb1270 RDI: 000000000000000b RBP: 00007f2dcfe13f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 00007f2dcffe6038 R14: 00007f2dcffe5fa0 R15: 00007ffcbcf8e5f8 rcu: rcu_preempt kthread starved for 10565 jiffies! g74261 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:27640 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x14ed/0x5040 kernel/sched/core.c:6866 __schedule_loop kernel/sched/core.c:6948 [inline] schedule+0x165/0x360 kernel/sched/core.c:6963 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x11b0 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x9b/0x2d0 kernel/rcu/tree.c:2297 kthread+0x389/0x480 kernel/kthread.c:467 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 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 syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82 Code: cc cc cc cc cc cc cc 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 43 8e 2b 00 f3 0f 1e fa fb f4 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffffff8de07dc0 EFLAGS: 000002c2 RAX: 0000000000f12139 RBX: ffffffff819717be RCX: 0000000080000001 RDX: 0000000000000001 RSI: ffffffff8d99cce1 RDI: ffffffff8be082e0 RBP: ffffffff8de07eb0 R08: ffff8880b863375b R09: 1ffff110170c66eb R10: dffffc0000000000 R11: ffffed10170c66ec R12: ffffffff8fa23d70 R13: 1ffffffff1bd29b8 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888125c0c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffcd7975c9c CR3: 0000000038afa000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x73/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x1be/0x4d0 kernel/sched/idle.c:332 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:430 rest_init+0x2de/0x300 init/main.c:757 start_kernel+0x381/0x3d0 init/main.c:1206 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291 common_startup_64+0x13e/0x147