syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1):
 P16575/1:b..l

rcu: 	(detected by 1, t=10502 jiffies, g=79349, q=210 ncpus=2)
task:syz.8.2615      state:R
  running task     stack:25544 pid:16575 tgid:16570 ppid:13528  task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5298 [inline]
 __schedule+0x15dd/0x52d0 kernel/sched/core.c:6911
 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7238
 irqentry_exit+0x599/0x620 kernel/entry/common.c:239
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:kasan_check_range+0xb/0x2c0 mm/kasan/generic.c:199
Code: ae 16 8e e8 57 47 f8 fe 90 0f 0b 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 ae 01 00 00 4c 8d 04 37 49 39 f8 0f
RSP: 0018:ffffc90004b0ea90 EFLAGS: 00000246

RAX: ffffc90004b0fe20 RBX: 0000000000000010 RCX: ffffffff81768c9e
RDX: 0000000000000001 RSI: 0000000000000010 RDI: ffffc90004b0ebf8
RBP: 0000000000000000 R08: 0000000000000001 R09: ffffffff8e75e5e0
R10: dffffc0000000000 R11: ffffffff81b0c390 R12: ffffc90004b0ebf8
R13: 1ffff92000961d77 R14: ffffc90004b0ebf8 R15: ffffc90004b0ebf0
 __asan_memset+0x22/0x50 mm/kasan/shadow.c:84
 unwind_next_frame+0xeae/0x23c0 arch/x86/kernel/unwind_orc.c:607
 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
 save_stack+0x122/0x230 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+0x231/0x280 mm/page_alloc.c:1889
 prep_new_page mm/page_alloc.c:1897 [inline]
 get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3962
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5250
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2484
 folio_alloc_mpol_noprof mm/mempolicy.c:2503 [inline]
 vma_alloc_folio_noprof+0xea/0x210 mm/mempolicy.c:2538
 folio_prealloc mm/memory.c:-1 [inline]
 wp_page_copy mm/memory.c:3780 [inline]
 do_wp_page+0x1204/0x5a00 mm/memory.c:4241
 handle_pte_fault mm/memory.c:6333 [inline]
 __handle_mm_fault mm/memory.c:6455 [inline]
 handle_mm_fault+0x1520/0x3310 mm/memory.c:6624
 do_user_addr_fault+0x75b/0x1340 arch/x86/mm/fault.c:1385
 handle_page_fault arch/x86/mm/fault.c:1474 [inline]
 exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1527
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0010:__put_user_nocheck_4+0x3/0x10 arch/x86/lib/putuser.S:104
Code: d9 0f 01 cb 89 01 31 c9 0f 01 ca e9 e2 1d 62 f5 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 01 cb <89> 01 31 c9 0f 01 ca e9 bc 1d 62 f5 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90004b0f8b8 EFLAGS: 00050202

RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000200000252030
RDX: ffff888050121e80 RSI: 0000000000000002 RDI: 00000000ffffffff
RBP: ffffc90004b0fa30 R08: ffffc90004b0f687 R09: 1ffff92000961ed0
R10: dffffc0000000000 R11: fffff52000961ed1 R12: 1ffff92000961f24
R13: 0000000000000002 R14: 0000200000252000 R15: dffffc0000000000
 ____sys_recvmsg+0x2be/0x4a0 net/socket.c:2825
 ___sys_recvmsg+0x215/0x590 net/socket.c:2854
 do_recvmmsg+0x334/0x800 net/socket.c:2949
 __sys_recvmmsg net/socket.c:3023 [inline]
 __do_sys_recvmmsg net/socket.c:3046 [inline]
 __se_sys_recvmmsg net/socket.c:3039 [inline]
 __x64_sys_recvmmsg+0x198/0x250 net/socket.c:3039
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7febad39c799
RSP: 002b:00007febae236028 EFLAGS: 00000246
 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007febad616090 RCX: 00007febad39c799
RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000003
RBP: 00007febad432c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 00007febad616128 R14: 00007febad616090 R15: 00007ffdba9bd2b8
 </TASK>
rcu: rcu_preempt kthread starved for 9856 jiffies! g79349 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:27744 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5298 [inline]
 __schedule+0x15dd/0x52d0 kernel/sched/core.c:6911
 __schedule_loop kernel/sched/core.c:6993 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7008
 schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095
 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
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 02/12/2026
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63
Code: 6e 6c 02 e9 8e 92 61 f5 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 e3 b2 1a 00 fb f4 <e9> 67 92 61 f5 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90
RSP: 0018:ffffc90000197e20 EFLAGS: 00000242

RAX: 000000000321a557 RBX: ffffffff819a913a RCX: 0000000080000001
RDX: 0000000000000001 RSI: ffffffff8def8cb4 RDI: ffffffff8c27c900
RBP: ffffc90000197f10 R08: ffff8880b873399b R09: 1ffff110170e6733
R10: dffffc0000000000 R11: ffffed10170e6734 R12: 0000000000000001
R13: 1ffff11003ad0000 R14: 0000000000000001 R15: 1ffff11003ad0000
FS:  0000000000000000(0000) GS:ffff88812555d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe81794c34d CR3: 00000000310a8000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/kernel/process.c:766 [inline]
 default_idle+0x9/0x20 arch/x86/kernel/process.c:767
 default_idle_call+0x72/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:199 [inline]
 do_idle+0x36a/0x5f0 kernel/sched/idle.c:352
 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:451
 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312
 common_startup_64+0x13e/0x147
 </TASK>