syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P24717/1:b..l
	(detected by 0, t=10502 jiffies, g=260865, q=209 ncpus=2)
task:syz.4.4600      state:R  running task     stack:26528 pid:24717 ppid:24053  flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10e9/0x40d0 kernel/sched/core.c:6561
 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6873
 irqentry_exit+0x63/0x70 kernel/entry/common.c:439
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:__preempt_count_add kernel/rcu/tree.c:717 [inline]
RIP: 0010:rcu_is_watching+0x2/0xa0 kernel/rcu/tree.c:720
Code: eb 99 e8 c1 3e a4 08 48 c7 c7 60 14 93 8c 4c 89 f6 e8 a2 04 c4 02 e9 53 ff ff ff 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 41 57 <41> 56 53 65 ff 05 dc 6c 97 7e e8 3f 53 a4 08 89 c3 83 f8 08 73 60
RSP: 0018:ffffc90003667040 EFLAGS: 00000202
RAX: ffffffff81dc6352 RBX: 0000000000000001 RCX: 0000000000000002
RDX: ffff888030c70000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000140dca R08: dffffc0000000000 R09: ffffed100370d4aa
R10: ffffed100370d4aa R11: 1ffff1100370d4a9 R12: 0000000000000001
R13: 0000000000000000 R14: ffffea0001a5e840 R15: 0000000000000001
 rcu_read_unlock include/linux/rcupdate.h:820 [inline]
 page_ext_put+0x2b/0xb0 mm/page_ext.c:182
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2532
 prep_new_page mm/page_alloc.c:2539 [inline]
 get_page_from_freelist+0x1a26/0x1ac0 mm/page_alloc.c:4328
 __alloc_pages+0x1df/0x4e0 mm/page_alloc.c:5606
 __folio_alloc+0xe/0x30 mm/page_alloc.c:5638
 vma_alloc_folio+0x4a3/0x900 mm/mempolicy.c:2243
 alloc_page_vma include/linux/gfp.h:284 [inline]
 wp_page_copy+0x244/0x1640 mm/memory.c:3148
 handle_pte_fault mm/memory.c:5049 [inline]
 __handle_mm_fault mm/memory.c:5173 [inline]
 handle_mm_fault+0x1ca6/0x3e70 mm/memory.c:5294
 do_user_addr_fault+0x51f/0xb10 arch/x86/mm/fault.c:1340
 handle_page_fault arch/x86/mm/fault.c:1431 [inline]
 exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1487
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:608
RIP: 0010:__put_user_nocheck_4+0x3/0x11
Code: 00 00 48 39 d9 73 54 0f 01 cb 66 89 01 31 c9 0f 01 ca c3 90 90 90 90 90 48 bb fd ef ff ff ff 7f 00 00 48 39 d9 73 34 0f 01 cb <89> 01 31 c9 0f 01 ca c3 90 90 90 90 90 90 48 bb f9 ef ff ff ff 7f
RSP: 0018:ffffc900036678d8 EFLAGS: 00050202
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000200000259030
RDX: ffff888030c70000 RSI: 0000000000000002 RDI: 00000000ffffffff
RBP: ffffc90003667a70 R08: dffffc0000000000 R09: fffff520006cced9
R10: fffff520006cced9 R11: 1ffff920006cced8 R12: dffffc0000000000
R13: 0000200000259000 R14: 0000000000000000 R15: 0000000000000002
 ____sys_recvmsg+0x367/0x580 net/socket.c:2751
 ___sys_recvmsg+0x1b2/0x510 net/socket.c:2780
 do_recvmmsg+0x359/0x7d0 net/socket.c:2874
 __sys_recvmmsg net/socket.c:2953 [inline]
 __do_sys_recvmmsg net/socket.c:2976 [inline]
 __se_sys_recvmmsg net/socket.c:2969 [inline]
 __x64_sys_recvmmsg+0x18d/0x240 net/socket.c:2969
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f161d98e969
RSP: 002b:00007f161e82a038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007f161dbb6080 RCX: 00007f161d98e969
RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000005
RBP: 00007f161da10ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f161dbb6080 R15: 00007ffceb6dc7e8
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 9890 jiffies! g260865 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=170472
rcu: rcu_preempt kthread starved for 9896 jiffies! g260865 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:26272 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10e9/0x40d0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1965
 rcu_gp_fqs_loop+0x2f2/0x1310 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0x95/0x380 kernel/rcu/tree.c:1905
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.1.138-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
RIP: 0010:default_idle+0xb/0x10 arch/x86/kernel/process.c:736
Code: 48 89 df e8 c7 1a b9 f7 e9 4c ff ff ff e8 4d 14 f6 ff 00 00 cc cc 00 00 cc cc 00 00 cc cc 00 66 90 0f 00 2d b7 72 4d 00 fb f4 <c3> 0f 1f 40 00 41 57 41 56 53 49 be 00 00 00 00 00 fc ff df 65 48
RSP: 0018:ffffffff8c607d88 EFLAGS: 000002c6
RAX: 68230c48c4f5dd00 RBX: ffffffff8a1930d7 RCX: 68230c48c4f5dd00
RDX: 0000000000000001 RSI: ffffffff8a6bfe00 RDI: ffffffff8abf0da0
RBP: ffffffff8c607ec0 R08: dffffc0000000000 R09: ffffed10171c6aee
R10: ffffed10171c6aee R11: 1ffff110171c6aed R12: 0000000000000000
R13: dffffc0000000000 R14: ffffffff8c6bc680 R15: 1ffffffff1bfd086
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2f40fff8 CR3: 000000000c68e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 default_idle_call+0x84/0xc0 kernel/sched/idle.c:109
 cpuidle_idle_call kernel/sched/idle.c:191 [inline]
 do_idle+0x1fc/0x570 kernel/sched/idle.c:303
 cpu_startup_entry+0x3f/0x60 kernel/sched/idle.c:401
 rest_init+0x2dc/0x300 init/main.c:733
 arch_call_rest_init+0xa/0xa init/main.c:893
 start_kernel+0x490/0x539 init/main.c:1140
 secondary_startup_64_no_verify+0xcf/0xdb
 </TASK>