rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P11171/1:b..l P11174/1:b..l rcu: (detected by 0, t=10503 jiffies, g=54673, q=651 ncpus=2) task:syz.9.1296 state:R running task stack:24864 pid:11174 tgid:11165 ppid:9770 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x150e/0x5070 kernel/sched/core.c:6866 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7193 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:trace_lock_release include/trace/events/lock.h:69 [inline] RIP: 0010:lock_release+0x44/0x3b0 kernel/locking/lockdep.c:5879 Code: 8b 05 b0 11 01 11 48 89 44 24 28 0f 1f 44 00 00 65 8b 05 b3 11 01 11 83 f8 08 0f 83 87 02 00 00 89 c0 48 0f a3 05 dc 90 03 0e <73> 0d e8 f5 f8 08 00 84 c0 0f 84 a3 02 00 00 83 3d f6 c0 03 0e 00 RSP: 0018:ffffc9000b76ec30 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffffffff90414101 RCX: a233ca872a15fc00 RDX: ffffc9000b76ed01 RSI: ffffffff81742f85 RDI: ffffffff8e13f2e0 RBP: dffffc0000000000 R08: ffffc9000b76fad0 R09: 0000000000000000 R10: ffffc9000b76edb8 R11: fffff520016eddb9 R12: ffffc9000b76fae0 R13: ffffffff81742f85 R14: ffffffff8e13f2e0 R15: ffffffff81742f85 rcu_lock_release include/linux/rcupdate.h:341 [inline] rcu_read_unlock include/linux/rcupdate.h:897 [inline] class_rcu_destructor include/linux/rcupdate.h:1195 [inline] unwind_next_frame+0x1ab1/0x23d0 arch/x86/kernel/unwind_orc.c:695 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:165 __set_page_owner+0x8d/0x4c0 mm/page_owner.c:341 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x234/0x290 mm/page_alloc.c:1857 prep_new_page mm/page_alloc.c:1865 [inline] get_page_from_freelist+0x2365/0x2440 mm/page_alloc.c:3915 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5210 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2486 folio_alloc_mpol_noprof+0x39/0x70 mm/mempolicy.c:2505 shmem_alloc_folio mm/shmem.c:1902 [inline] shmem_alloc_and_add_folio+0x423/0xf40 mm/shmem.c:1944 shmem_get_folio_gfp+0x59d/0x1660 mm/shmem.c:2568 shmem_fault+0x179/0x390 mm/shmem.c:2769 __do_fault+0x138/0x390 mm/memory.c:5320 do_read_fault mm/memory.c:5755 [inline] do_fault mm/memory.c:5889 [inline] do_pte_missing+0x2208/0x3330 mm/memory.c:4401 handle_pte_fault mm/memory.c:6273 [inline] __handle_mm_fault mm/memory.c:6411 [inline] handle_mm_fault+0x1b26/0x32b0 mm/memory.c:6580 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:3748 [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/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fdaca98f749 RSP: 002b:00007fdacb748038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007fdacabe6180 RCX: 00007fdaca98f749 RDX: 0000000000000002 RSI: 0000000000b36000 RDI: 0000200000000000 RBP: 00007fdacaa13f91 R08: ffffffffffffffff R09: 000000006a855000 R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fdacabe6218 R14: 00007fdacabe6180 R15: 00007ffefdfd2448 task:syz.9.1296 state:R running task stack:24008 pid:11171 tgid:11165 ppid:9770 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x150e/0x5070 kernel/sched/core.c:6866 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7193 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:kasan_check_range+0x0/0x2c0 mm/kasan/generic.c:199 Code: ec ff 48 89 df 48 c7 c6 00 fe b7 8d e8 59 c1 ff fe 90 0f 0b cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <0f> 1f 40 d6 55 41 57 41 56 41 55 41 54 53 b0 01 48 85 f6 0f 84 ba RSP: 0018:ffffc9000b6ced10 EFLAGS: 00000246 RAX: ffffc9000b6cf2e0 RBX: 0000000000000010 RCX: ffffffff81743d8e RDX: 0000000000000001 RSI: 0000000000000010 RDI: ffffc9000b6cee58 RBP: 0000000000000000 R08: 0000000000000001 R09: ffffffff8e13f2e0 R10: ffffc9000b6cee58 R11: ffffffff81ad9d50 R12: ffffc9000b6cee58 R13: 1ffff920016d9dc3 R14: ffffc9000b6cee58 R15: ffffc9000b6cee50 __asan_memset+0x22/0x50 mm/kasan/shadow.c:84 unwind_next_frame+0xeae/0x23d0 arch/x86/kernel/unwind_orc.c:607 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4953 [inline] slab_alloc_node mm/slub.c:5267 [inline] kmem_cache_alloc_node_noprof+0x43c/0x720 mm/slub.c:5319 __alloc_skb+0x255/0x430 net/core/skbuff.c:679 alloc_skb include/linux/skbuff.h:1383 [inline] __ip_append_data+0x2dae/0x40c0 net/ipv4/ip_output.c:1133 ip_append_data+0x10e/0x190 net/ipv4/ip_output.c:1378 raw_sendmsg+0x13d8/0x18b0 net/ipv4/raw.c:651 sock_sendmsg_nosec+0x128/0x1d0 net/socket.c:737 __sock_sendmsg net/socket.c:752 [inline] ____sys_sendmsg+0x577/0x880 net/socket.c:2610 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2664 __sys_sendmmsg+0x227/0x430 net/socket.c:2753 __do_sys_sendmmsg net/socket.c:2780 [inline] __se_sys_sendmmsg net/socket.c:2777 [inline] __x64_sys_sendmmsg+0xa0/0xc0 net/socket.c:2777 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fdaca98f749 RSP: 002b:00007fdacb769038 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 00007fdacabe6090 RCX: 00007fdaca98f749 RDX: 00000000000a8000 RSI: 00002000000034c0 RDI: 0000000000000007 RBP: 00007fdacaa13f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000040000840 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fdacabe6128 R14: 00007fdacabe6090 R15: 00007ffefdfd2448 rcu: rcu_preempt kthread starved for 10613 jiffies! g54673 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:27200 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x150e/0x5070 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+0x301/0x1540 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+0x599/0xb30 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 0 to CPUs 1: NMI backtrace for cpu 1 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 10/25/2025 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 33 9e 2a 00 f3 0f 1e fa fb f4 48 ee 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: ea53de09fc64c000 RBX: ffffffff819786ba RCX: ea53de09fc64c000 RDX: 0000000000000001 RSI: ffffffff8d997e54 RDI: ffffffff8be07960 RBP: ffffc90000197f10 R08: ffff8880b87336db R09: 1ffff110170e66db R10: dffffc0000000000 R11: ffffed10170e66dc R12: ffffffff8fa22f70 R13: 1ffff11003adbb70 R14: 0000000000000001 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff888125d25000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c3d5d94 CR3: 0000000063c9c000 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+0x1ea/0x520 kernel/sched/idle.c:332 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:430 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312 common_startup_64+0x13e/0x147