syzbot

hrtimer: interrupt took 53496 ns
rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-...!: (1 GPs behind) idle=70f4/1/0x4000000000000000 softirq=12123/12124 fqs=0
rcu: 	(t=10501 jiffies g=10377 q=740 ncpus=2)
rcu: rcu_preempt kthread starved for 10502 jiffies! g10377 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:27880 pid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5381 [inline]
 __schedule+0x1553/0x45a0 kernel/sched/core.c:6700
 schedule+0xbd/0x170 kernel/sched/core.c:6774
 schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168
 rcu_gp_fqs_loop+0x313/0x1590 kernel/rcu/tree.c:1667
 rcu_gp_kthread+0x9d/0x3b0 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: 5942 Comm: syz.0.20 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:pv_native_safe_halt+0xf/0x10 arch/x86/kernel/paravirt.c:148
Code: d7 22 02 c3 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 83 e1 43 00 fb f4 <c3> 66 0f 1f 00 55 41 57 41 56 41 54 53 50 8b 2f eb 2e 41 89 de 80
RSP: 0018:ffffc90003407878 EFLAGS: 000002d3
RAX: ffffffff813aa578 RBX: 0000000000000003 RCX: ffff888030203c00
RDX: 0000000000000000 RSI: ffffffff8acac900 RDI: ffffffff8b1c81e0
RBP: ffffc90003407950 R08: ffffffff911bf5cf R09: 1ffffffff2237eb9
R10: dffffc0000000000 R11: fffffbfff2237eba R12: dffffc0000000000
R13: 0000000000000200 R14: 0000000000000003 R15: 1ffff92000680f14
FS:  000055558d4ca500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fda20d4da08 CR3: 000000007b15f000 CR4: 00000000003506e0
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline]
 kvm_wait+0x23d/0x2a0 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+0x23e/0x2c0 kernel/locking/spinlock_debug.c:115
 spin_lock include/linux/spinlock.h:351 [inline]
 futex_unqueue+0x4e/0xf0 kernel/futex/core.c:597
 futex_wait+0x1f4/0x5e0 kernel/futex/waitwake.c:660
 do_futex+0x2ff/0x3e0 kernel/futex/syscalls.c:134
 __do_sys_futex kernel/futex/syscalls.c:211 [inline]
 __se_sys_futex+0x3a9/0x440 kernel/futex/syscalls.c:192
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fda1ff9bf79
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc10c8d3f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 000000000001b7d1 RCX: 00007fda1ff9bf79
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fda20215fac
RBP: 0000000000000032 R08: 0000000000745d1e R09: 0000000000000000
R10: 00007ffc10c8d500 R11: 0000000000000246 R12: 00007ffc10c8d520
R13: 00007fda20215fac R14: 000000000001b803 R15: 00007ffc10c8d500
 </TASK>
CPU: 0 PID: 5943 Comm: syz.0.20 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:get_random_u32+0x11/0x910 drivers/char/random.c:532
Code: 89 e7 e8 b2 90 34 fd e9 b9 fd ff ff e8 d8 67 dc fc e9 e7 fd ff ff 0f 1f 00 f3 0f 1e fa 55 48 89 e5 41 57 41 56 41 55 41 54 53 <48> 83 e4 e0 48 81 ec 40 01 00 00 65 48 8b 04 25 28 00 00 00 48 89
RSP: 0018:ffffc900000072a8 EFLAGS: 00000246
RAX: ffffffff890468dc RBX: ffff88807e076030 RCX: ffff88802da30000
RDX: 0000000000000100 RSI: 0000000000000001 RDI: 0000000000000001
RBP: ffffc900000072d0 R08: ffffffff911bf5cf R09: 1ffffffff2237eb9
R10: dffffc0000000000 R11: fffffbfff2237eba R12: ffff88807e076000
R13: ffff8880218f3a2c R14: 0000000000000001 R15: 1ffff1100fc0ec70
FS:  00007fda20dae6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000100000000 CR3: 000000007b15f000 CR4: 00000000003506f0
Call Trace:
 <IRQ>
 net_tx_rndhash include/net/sock.h:2204 [inline]
 sk_set_txhash include/net/sock.h:2212 [inline]
 sk_rethink_txhash include/net/sock.h:2218 [inline]
 tcp_rcv_spurious_retrans net/ipv4/tcp_input.c:4616 [inline]
 tcp_send_dupack+0x411/0x9c0 net/ipv4/tcp_input.c:4632
 tcp_validate_incoming+0xf13/0x2250 net/ipv4/tcp_input.c:5891
 tcp_rcv_established+0x7de/0x1d20 net/ipv4/tcp_input.c:6156
 tcp_v4_do_rcv+0x4ed/0xb80 net/ipv4/tcp_ipv4.c:1734
 tcp_v4_rcv+0x23bf/0x2af0 net/ipv4/tcp_ipv4.c:2166
 ip_protocol_deliver_rcu+0x20e/0x3f0 net/ipv4/ip_input.c:205
 ip_local_deliver_finish+0x2ca/0x510 net/ipv4/ip_input.c:233
 NF_HOOK+0x32d/0x3b0 include/linux/netfilter.h:304
 NF_HOOK+0x32d/0x3b0 include/linux/netfilter.h:304
 __netif_receive_skb_one_core net/core/dev.c:5621 [inline]
 __netif_receive_skb+0xcc/0x290 net/core/dev.c:5735
 process_backlog+0x391/0x6f0 net/core/dev.c:6063
 __napi_poll+0xc0/0x460 net/core/dev.c:6625
 napi_poll net/core/dev.c:6692 [inline]
 net_rx_action+0x616/0xc40 net/core/dev.c:6828
 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+0xd3/0x190 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:get_current arch/x86/include/asm/current.h:41 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x8/0x60 kernel/kcov.c:215
Code: 00 00 f3 0f 1e fa 53 48 89 fb e8 13 00 00 00 48 8b 3d 3c cc 03 0d 48 89 de 5b e9 53 59 57 00 cc cc cc f3 0f 1e fa 48 8b 04 24 <65> 48 8b 0d 10 a2 7c 7e 65 8b 15 11 a2 7c 7e 81 e2 00 01 ff 00 74
RSP: 0018:ffffc90003237af0 EFLAGS: 00000246
RAX: ffffffff8a73bba9 RBX: ffffc90003407c68 RCX: ffff88802da30000
RDX: 0000000000000000 RSI: ffffc90000a32948 RDI: ffffc90000a32948
RBP: ffffc90000a32948 R08: ffff888030203c2b R09: 1ffff11006040785
R10: dffffc0000000000 R11: ffffed1006040786 R12: ffffc90000a32948
R13: ffffc90000a32950 R14: ffffc90003407c68 R15: dffffc0000000000
 plist_check_list+0x229/0x240 lib/plist.c:49
 plist_check_head lib/plist.c:60 [inline]
 plist_del+0x6a/0x3f0 lib/plist.c:114
 __futex_unqueue+0xf0/0x160 kernel/futex/core.c:518
 futex_wake_mark+0xec/0x150 kernel/futex/waitwake.c:123
 futex_wake+0x32f/0x4f0 kernel/futex/waitwake.c:177
 do_futex+0x35d/0x3e0 kernel/futex/syscalls.c:139
 __do_sys_futex kernel/futex/syscalls.c:211 [inline]
 __se_sys_futex+0x3a9/0x440 kernel/futex/syscalls.c:192
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fda1ff9bf79
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fda20dae0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00007fda20215fa8 RCX: 00007fda1ff9bf79
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007fda20215fac
RBP: 00007fda20215fa0 R08: 0000000000745d1e R09: 0000000000000000
R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fda20216038 R14: 00007ffc10c8d1b0 R15: 00007ffc10c8d298
 </TASK>