rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P9004/1:b..l P9019/1:b..l rcu: (detected by 1, t=10502 jiffies, g=31249, q=541 ncpus=2) task:syz.3.817 state:R running task stack:23752 pid:9019 tgid:9018 ppid:5867 task_flags:0x40044c flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7256 irqentry_exit+0x6f/0x90 kernel/entry/common.c:211 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:rcu_preempt_read_exit kernel/rcu/tree_plugin.h:396 [inline] RIP: 0010:__rcu_read_unlock+0x33/0xe0 kernel/rcu/tree_plugin.h:435 Code: 55 41 54 53 49 bf 00 00 00 00 00 fc ff df 65 48 8b 3c 25 08 c0 91 92 48 8d 9f 84 04 00 00 49 89 dc 49 c1 ec 03 43 0f b6 04 3c <84> c0 75 4f ff 0b 75 1d 4c 8d b7 88 04 00 00 4c 89 f0 48 c1 e8 03 RSP: 0018:ffffc90015d570c0 EFLAGS: 00000a03 RAX: 0000000000000000 RBX: ffff88802ed1c104 RCX: 8e89a988673f0700 RDX: 0000000000000001 RSI: ffffffff8d9d6f6f RDI: ffff88802ed1bc80 RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff81cf6c46 R10: ffffc90015d571d8 R11: ffffffff81ac8430 R12: 1ffff11005da3820 R13: dffffc0000000000 R14: 00007f6764b8eec9 R15: dffffc0000000000 rcu_read_unlock include/linux/rcupdate.h:899 [inline] is_bpf_text_address+0x292/0x2b0 kernel/bpf/core.c:746 kernel_text_address+0xa5/0xe0 kernel/extable.c:125 __kernel_text_address+0xd/0x40 kernel/extable.c:79 unwind_get_return_address+0x4d/0x90 arch/x86/kernel/unwind_orc.c:369 arch_stack_walk+0xfc/0x150 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 poison_kmalloc_redzone mm/kasan/common.c:400 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:417 kasan_kmalloc include/linux/kasan.h:262 [inline] __kmalloc_cache_noprof+0x3d5/0x6f0 mm/slub.c:5748 kmalloc_noprof include/linux/slab.h:957 [inline] slab_free_hook mm/slub.c:2475 [inline] slab_free mm/slub.c:6612 [inline] kmem_cache_free+0x16f/0x690 mm/slub.c:6722 anon_vma_free mm/rmap.c:136 [inline] __put_anon_vma+0x12b/0x2d0 mm/rmap.c:2777 put_anon_vma include/linux/rmap.h:117 [inline] unlink_anon_vmas+0x503/0x670 mm/rmap.c:443 free_pgtables+0x72b/0x9c0 mm/memory.c:413 exit_mmap+0x43c/0xb40 mm/mmap.c:1291 __mmput+0x118/0x430 kernel/fork.c:1133 exit_mm+0x1da/0x2c0 kernel/exit.c:582 do_exit+0x648/0x2300 kernel/exit.c:954 do_group_exit+0x21c/0x2d0 kernel/exit.c:1107 get_signal+0x1285/0x1340 kernel/signal.c:3034 arch_do_signal_or_restart+0xa0/0x790 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop+0x72/0x130 kernel/entry/common.c:40 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f6764b8eec9 RSP: 002b:00007f67659520e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007f6764de5fa8 RCX: 00007f6764b8eec9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f6764de5fa8 RBP: 00007f6764de5fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f6764de6038 R14: 00007ffc09585840 R15: 00007ffc09585928 task:syz.2.814 state:R running task stack:25336 pid:9004 tgid:9002 ppid:5871 task_flags:0x400140 flags:0x00080001 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7256 irqentry_exit+0x6f/0x90 kernel/entry/common.c:211 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:deref_stack_reg+0x3/0x230 arch/x86/kernel/unwind_orc.c:402 Code: e8 c2 12 b2 00 48 8b 4c 24 18 e9 f2 fe ff ff 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 41 57 <41> 56 41 55 41 54 53 48 83 ec 20 48 89 54 24 18 49 89 f0 49 89 ff RSP: 0018:ffffc9000ed1ed20 EFLAGS: 00000283 RAX: fffffffffffffff0 RBX: ffffffff90380e50 RCX: 0000000000000000 RDX: ffffc9000ed1ee48 RSI: ffffc9000ed1fdb0 RDI: ffffc9000ed1ee08 RBP: dffffc0000000000 R08: ffffc9000ed1ee67 R09: 0000000000000000 R10: ffffc9000ed1ee58 R11: fffff52001da3dcd R12: ffffc9000ed1fdb0 R13: ffffc9000ed1ee58 R14: ffffc9000ed1ee08 R15: 1ffffffff20701ca unwind_next_frame+0x17c4/0x2390 arch/x86/kernel/unwind_orc.c:-1 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 save_stack+0xf5/0x1f0 mm/page_owner.c:156 __set_page_owner+0x8d/0x4c0 mm/page_owner.c:332 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1850 prep_new_page mm/page_alloc.c:1858 [inline] get_page_from_freelist+0x2365/0x2440 mm/page_alloc.c:3884 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5183 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416 folio_alloc_mpol_noprof+0x39/0x70 mm/mempolicy.c:2435 shmem_alloc_folio mm/shmem.c:1871 [inline] shmem_alloc_and_add_folio+0x447/0xf60 mm/shmem.c:1910 shmem_get_folio_gfp+0x59d/0x1660 mm/shmem.c:2533 shmem_fault+0x179/0x390 mm/shmem.c:2734 __do_fault+0x138/0x390 mm/memory.c:5280 do_read_fault mm/memory.c:5698 [inline] do_fault mm/memory.c:5832 [inline] do_pte_missing mm/memory.c:4361 [inline] handle_pte_fault mm/memory.c:6177 [inline] __handle_mm_fault+0x35e3/0x5400 mm/memory.c:6318 handle_mm_fault+0x40a/0x8e0 mm/memory.c:6487 faultin_page mm/gup.c:1126 [inline] __get_user_pages+0x165c/0x2a00 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:3471 [inline] vm_mmap_pgoff+0x387/0x4d0 mm/util.c:586 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe45d98eec9 RSP: 002b:00007fe45e90e038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007fe45dbe5fa0 RCX: 00007fe45d98eec9 RDX: b635773f06ebbeef RSI: 0000000000b36000 RDI: 0000200000000000 RBP: 00007fe45da11f91 R08: ffffffffffffffff R09: 0000000000000000 R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fe45dbe6038 R14: 00007fe45dbe5fa0 R15: 00007fffbdd1f4f8 rcu: rcu_preempt kthread starved for 10368 jiffies! g31249 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:27272 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 __schedule_loop kernel/sched/core.c:7011 [inline] schedule+0x165/0x360 kernel/sched/core.c:7026 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 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 10/02/2025 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 53 b1 1a 00 f3 0f 1e fa fb f4 c8 e6 02 00 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc90000197de0 EFLAGS: 000002c6 RAX: de73682fd1e4df00 RBX: ffffffff8196d367 RCX: de73682fd1e4df00 RDX: 0000000000000001 RSI: ffffffff8d7edf31 RDI: ffffffff8bc07a60 RBP: ffffc90000197f10 R08: ffff8880b8732fdb R09: 1ffff110170e65fb R10: dffffc0000000000 R11: ffffed10170e65fc R12: ffffffff8f9e2770 R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff11003a54b58 FS: 0000000000000000(0000) GS:ffff888125e04000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055d12bebff28 CR3: 0000000079036000 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:190 [inline] do_idle+0x1e7/0x510 kernel/sched/idle.c:330 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:315 common_startup_64+0x13e/0x147