rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6027/1:b..l rcu: (detected by 1, t=10506 jiffies, g=13049, q=595 ncpus=2) task:syz.1.56 state:R running task stack:26024 pid:6027 tgid:6026 ppid:5606 task_flags:0x400040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5387 [inline] __schedule+0x10e9/0x6820 kernel/sched/core.c:7188 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7512 irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:476 [inline] irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:547 [inline] irqentry_exit+0x1fe/0x790 kernel/entry/common.c:164 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_release+0x19e/0x310 kernel/locking/lockdep.c:5893 Code: ff 65 0f c1 05 9b 3e 26 12 83 f8 01 0f 85 28 01 00 00 9c 58 f6 c4 02 0f 85 13 01 00 00 41 f7 c6 00 02 00 00 0f 85 c0 00 00 00 <48> 8b 44 24 10 65 48 2b 05 ed f6 25 12 0f 85 4e 01 00 00 48 83 c4 RSP: 0018:ffffc90003f87490 EFLAGS: 00000206 RAX: 0000000000000046 RBX: ffffffff8e7e54e0 RCX: ffffc90003f8749c RDX: 0000000000000001 RSI: ffffffff8def932e RDI: ffffffff8c1c3480 RBP: ffffffff824536ed R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffff88802a6e4a00 R13: ffffc90003f87500 R14: 0000000000000202 R15: 0000000000000002 rcu_lock_release include/linux/rcupdate.h:310 [inline] rcu_read_unlock include/linux/rcupdate.h:869 [inline] filemap_get_entry+0x232/0x450 mm/filemap.c:1919 shmem_get_folio_gfp+0x221/0x1900 mm/shmem.c:2488 shmem_fault+0x1f9/0xa20 mm/shmem.c:2765 __do_fault+0x10b/0x440 mm/memory.c:5458 do_read_fault mm/memory.c:5893 [inline] do_fault+0xa99/0x1750 mm/memory.c:6027 do_pte_missing mm/memory.c:4550 [inline] handle_pte_fault mm/memory.c:6411 [inline] __handle_mm_fault+0x187d/0x2a00 mm/memory.c:6549 handle_mm_fault+0x36d/0xa20 mm/memory.c:6718 faultin_page mm/gup.c:1126 [inline] __get_user_pages+0x1178/0x32a0 mm/gup.c:1428 populate_vma_page_range+0x267/0x3f0 mm/gup.c:1860 __mm_populate+0x107/0x3a0 mm/gup.c:1963 mm_populate include/linux/mm.h:4137 [inline] vm_mmap_pgoff+0x37f/0x470 mm/util.c:586 ksys_mmap_pgoff+0xe4/0x610 mm/mmap.c:606 __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+0x10b/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe057f9cdd9 RSP: 002b:00007fe058e5c028 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007fe058215fa0 RCX: 00007fe057f9cdd9 RDX: b635773f06ebbeef RSI: 0000000000b36000 RDI: 0000200000000000 RBP: 00007fe058032d69 R08: ffffffffffffffff R09: 00000000c8b93000 R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fe058216038 R14: 00007fe058215fa0 R15: 00007fffca614538 rcu: rcu_preempt kthread starved for 10502 jiffies! g13049 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:28216 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5387 [inline] __schedule+0x10e9/0x6820 kernel/sched/core.c:7188 __schedule_loop kernel/sched/core.c:7267 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7282 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2297 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63 Code: 96 93 02 e9 c3 42 03 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 a3 e0 21 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:ffffc90000197df0 EFLAGS: 00000242 RAX: 00000000003bdf8f RBX: ffff88801e2c2500 RCX: ffffffff8b89b045 RDX: 0000000000000000 RSI: ffffffff8df1e844 RDI: ffffffff8c1c3480 RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed10170a67b5 R10: ffff8880b8533dab R11: 0000000000000000 R12: 0000000000000001 R13: ffffed1003c584a0 R14: 0000000000000001 R15: ffffffff90d78850 FS: 0000000000000000(0000) GS:ffff888124479000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b332fdff8 CR3: 000000005fa8d000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:62 [inline] default_idle+0x9/0x10 arch/x86/kernel/process.c:767 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:199 [inline] do_idle+0x464/0x590 kernel/sched/idle.c:352 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:451 start_secondary+0x21d/0x2d0 arch/x86/kernel/smpboot.c:312 common_startup_64+0x13e/0x148