syzbot

rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-...!: (1 GPs behind) idle=63ac/1/0x4000000000000000 softirq=9338/9339 fqs=1493
rcu: 	(t=10502 jiffies g=6973 q=100468 ncpus=2)
rcu: rcu_preempt kthread timer wakeup didn't happen for 7508 jiffies! g6973 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=3873
rcu: rcu_preempt kthread starved for 7511 jiffies! g6973 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27088 pid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 schedule+0xbd/0x170 kernel/sched/core.c:6773
 schedule_timeout+0x160/0x280 kernel/time/timer.c:2167
 rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667
 rcu_gp_kthread+0x99/0x380 kernel/rcu/tree.c:1866
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 9844 Comm: syz-executor269 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:148
Code: cc cc cc cc cc cc cc f3 0f 1e fa 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 66 90 0f 00 2d a3 16 3a 00 f3 0f 1e fa fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc 66 0f 1f 00 55 41 57 41 56
RSP: 0018:ffffc900001f0818 EFLAGS: 00000246
RAX: ffffffff813a13aa RBX: 0000000000000003 RCX: ffff888076b29e00
RDX: 0000000000000100 RSI: ffffffff8aaabaa0 RDI: ffffffff8afc70c0
RBP: ffffc900001f08f0 R08: ffffffff90da55cf R09: 1ffffffff21b4ab9
R10: dffffc0000000000 R11: fffffbfff21b4aba R12: dffffc0000000000
R13: 0000000000000200 R14: 0000000000000003 R15: 1ffff9200003e108
FS:  000055555798b380(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7b6858000f CR3: 000000007a344000 CR4: 00000000003506e0
Call Trace:
 <IRQ>
 arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline]
 kvm_wait+0x22f/0x290 arch/x86/kernel/kvm.c:1058
 pv_wait arch/x86/include/asm/paravirt.h:598 [inline]
 pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:470 [inline]
 __pv_queued_spin_lock_slowpath+0x61a/0x9d0 kernel/locking/qspinlock.c:511
 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:586 [inline]
 queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline]
 queued_spin_lock include/asm-generic/qspinlock.h:114 [inline]
 do_raw_spin_lock+0x24e/0x2c0 kernel/locking/spinlock_debug.c:115
 spin_lock include/linux/spinlock.h:351 [inline]
 __xfrm_state_delete+0xba/0x800 net/xfrm/xfrm_state.c:746
 xfrm_timer_handler+0x1c3/0x9e0 net/xfrm/xfrm_state.c:644
 __run_hrtimer kernel/time/hrtimer.c:1755 [inline]
 __hrtimer_run_queues+0x51e/0xc40 kernel/time/hrtimer.c:1819
 hrtimer_run_softirq+0x187/0x2b0 kernel/time/hrtimer.c:1836
 handle_softirqs+0x280/0x820 kernel/softirq.c:578
 __do_softirq kernel/softirq.c:612 [inline]
 invoke_softirq kernel/softirq.c:452 [inline]
 __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661
 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:unwind_next_frame+0x14d/0x2970 arch/x86/kernel/unwind_orc.c:494
Code: ec 4a 00 e9 26 21 00 00 e8 10 ec 4a 00 eb 05 e8 09 ec 4a 00 4c 89 7c 24 78 4d 8d 74 24 35 4c 89 f0 48 c1 e8 03 48 89 44 24 38 <42> 0f b6 04 28 84 c0 48 8b 5c 24 20 0f 85 64 21 00 00 45 0f b6 3e
RSP: 0018:ffffc90004aaf298 EFLAGS: 00000a03
RAX: 1ffff92000955e73 RBX: 1ffff92000955e6d RCX: ffff888076b29e00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffffff813aa37e
RBP: ffffc90004aaf3b8 R08: ffffc90004aaf430 R09: 0000000000000002
R10: 0000000000000004 R11: 0000000000000000 R12: ffffc90004aaf368
R13: dffffc0000000000 R14: ffffc90004aaf39d R15: ffffffff81dc1bfe
 arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:52
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:328
 kasan_slab_alloc include/linux/kasan.h:188 [inline]
 slab_post_alloc_hook+0x6e/0x4d0 mm/slab.h:767
 slab_alloc_node mm/slub.c:3495 [inline]
 slab_alloc mm/slub.c:3503 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3510 [inline]
 kmem_cache_alloc+0x11e/0x2e0 mm/slub.c:3519
 kmem_cache_zalloc include/linux/slab.h:711 [inline]
 lsm_inode_alloc security/security.c:633 [inline]
 security_inode_alloc+0x34/0x110 security/security.c:1494
 inode_init_always+0x8fc/0xc90 fs/inode.c:232
 alloc_inode fs/inode.c:268 [inline]
 new_inode_pseudo+0x95/0x1d0 fs/inode.c:1049
 new_inode+0x22/0x1b0 fs/inode.c:1075
 proc_pid_make_inode+0x24/0x190 fs/proc/base.c:1956
 proc_pident_instantiate+0x6d/0x2b0 fs/proc/base.c:2703
 proc_pident_lookup+0x1b3/0x290 fs/proc/base.c:2739
 lookup_open fs/namei.c:3466 [inline]
 open_last_lookups fs/namei.c:3556 [inline]
 path_openat+0x10b8/0x3190 fs/namei.c:3786
 do_filp_open+0x1c5/0x3d0 fs/namei.c:3816
 do_sys_openat2+0x12c/0x1c0 fs/open.c:1419
 do_sys_open fs/open.c:1434 [inline]
 __do_sys_openat fs/open.c:1450 [inline]
 __se_sys_openat fs/open.c:1445 [inline]
 __x64_sys_openat+0x139/0x160 fs/open.c:1445
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f7b6853d311
Code: 75 57 89 f0 25 00 00 41 00 3d 00 00 41 00 74 49 80 3d 5a 2d 07 00 00 74 6d 89 da 48 89 ee bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 0f 87 93 00 00 00 48 8b 54 24 28 64 48 2b 14 25
RSP: 002b:00007fff14c1e610 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000080001 RCX: 00007f7b6853d311
RDX: 0000000000080001 RSI: 00007f7b68580014 RDI: 00000000ffffff9c
RBP: 00007f7b68580014 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00007fff14c1e6b0
R13: 00007fff14c1ebd0 R14: 00007fff14c1ebb0 R15: 0000000000000522
 </TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.873 msecs
CPU: 0 PID: 5809 Comm: syz-executor269 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:xfrm_state_lookup_spi_proto net/xfrm/xfrm_state.c:1477 [inline]
RIP: 0010:xfrm_alloc_spi+0x3ae/0x11f0 net/xfrm/xfrm_state.c:2302
Code: 38 00 74 08 4c 89 f7 e8 e0 96 be f8 4d 8b 36 4d 85 f6 0f 94 c0 49 83 c6 d8 0f 94 c1 08 c1 74 0a e8 a7 4b 67 f8 e9 2d 02 00 00 <4d> 8d a6 a0 00 00 00 4c 89 e0 48 c1 e8 03 42 0f b6 04 38 84 c0 0f
RSP: 0018:ffffc9000467f1a0 EFLAGS: 00000293
RAX: ffffffff891e460a RBX: 0000000002000000 RCX: ffff8880799c3c00
RDX: 0000000000000000 RSI: 0000000002000000 RDI: 0000000001000000
RBP: ffffc9000467f2f0 R08: dffffc0000000000 R09: 1ffffffff21b4aa0
R10: dffffc0000000000 R11: fffffbfff21b4aa1 R12: 0000000001000000
R13: 0000000000000000 R14: ffff888025e14400 R15: dffffc0000000000
FS:  000055555798b380(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000000006c8 CR3: 000000002bea9000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 xfrm_alloc_userspi+0x5d1/0xa90 net/xfrm/xfrm_user.c:1623
 xfrm_user_rcv_msg+0x596/0x870 net/xfrm/xfrm_user.c:3169
 netlink_rcv_skb+0x216/0x480 net/netlink/af_netlink.c:2545
 xfrm_netlink_rcv+0x79/0x90 net/xfrm/xfrm_user.c:3191
 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
 netlink_unicast+0x751/0x8d0 net/netlink/af_netlink.c:1346
 netlink_sendmsg+0x8c1/0xbe0 net/netlink/af_netlink.c:1894
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 ____sys_sendmsg+0x5bf/0x950 net/socket.c:2595
 ___sys_sendmsg+0x220/0x290 net/socket.c:2649
 __sys_sendmsg net/socket.c:2678 [inline]
 __do_sys_sendmsg net/socket.c:2687 [inline]
 __se_sys_sendmsg+0x1a5/0x270 net/socket.c:2685
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f7b6853e449
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 31 1b 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff14c1eb78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f7b6853e449
RDX: 0000000000048040 RSI: 00002000000006c0 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff14c1eb9c
R13: 00007f7b68580100 R14: 00007fff14c1ebb0 R15: 0000000000000003
 </TASK>