syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P11606/1:b..l
	(detected by 1, t=10502 jiffies, g=22529, q=1901 ncpus=2)
task:syz.0.2379      state:R  running task     stack:26576 pid:11606 ppid:4410   flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6874
 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:lock_acquire+0x225/0x4a0 kernel/locking/lockdep.c:5666
Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3d 04 f8 0f 85 f0 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 43 c7 44 3d 08 00 00 00 00 65 48 8b 04
RSP: 0018:ffffc9000ca3f080 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: e137af94277f7d00
RDX: 0000000000000000 RSI: ffffffff8a8c2220 RDI: ffffffff8adf0d20
RBP: ffffc9000ca3f198 R08: dffffc0000000000 R09: 1ffffffff215ee48
R10: dffffc0000000000 R11: fffffbfff215ee49 R12: 0000000000000000
R13: 1ffff92001947e1c R14: 0000000000000246 R15: dffffc0000000000
 rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 rcu_read_lock include/linux/rcupdate.h:791 [inline]
 net_generic+0x3a/0x240 include/net/netns/generic.h:45
 tipc_sk_lookup+0xa6/0x910 net/tipc/socket.c:2999
 tipc_sk_rcv+0x408/0x2be0 net/tipc/socket.c:2494
 tipc_node_xmit+0x212/0xf70 net/tipc/node.c:1703
 __tipc_sendstream+0xb0f/0x12f0 net/tipc/socket.c:1626
 tipc_sendstream+0x51/0x70 net/tipc/socket.c:1550
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 ____sys_sendmsg+0x5be/0x970 net/socket.c:2518
 ___sys_sendmsg+0x2a2/0x360 net/socket.c:2572
 __sys_sendmsg net/socket.c:2601 [inline]
 __do_sys_sendmsg net/socket.c:2610 [inline]
 __se_sys_sendmsg+0x1bb/0x2a0 net/socket.c:2608
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f8a5899c819
RSP: 002b:00007f8a59863028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f8a58c15fa0 RCX: 00007f8a5899c819
RDX: 0000000000000000 RSI: 0000200000003280 RDI: 0000000000000004
RBP: 00007f8a58a32c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8a58c16038 R14: 00007f8a58c15fa0 R15: 00007ffc543ca9b8
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10547 jiffies! g22529 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=21283
rcu: rcu_preempt kthread starved for 10548 jiffies! g22529 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:27760 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
 schedule+0xb9/0x180 kernel/sched/core.c:6638
 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2168
 rcu_gp_fqs_loop+0x303/0x1340 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0x99/0x3b0 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:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 11608 Comm: syz.1.2378 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:__lock_release kernel/locking/lockdep.c:5366 [inline]
RIP: 0010:lock_release+0x2ce/0x920 kernel/locking/lockdep.c:5682
Code: 85 d3 04 00 00 45 89 2e 45 85 ff 49 bd 00 00 00 00 00 fc ff df 4c 8b 7c 24 18 0f 85 88 02 00 00 48 8b 44 24 40 42 0f b6 04 28 <84> c0 0f 85 80 04 00 00 48 8b 04 24 89 10 4c 89 e0 48 c1 e8 03 42
RSP: 0018:ffffc9000cb1e420 EFLAGS: 00000083
RAX: 0000000000000000 RBX: 1ffff1100357216a RCX: 0000000000000001
RDX: 0000000000000002 RSI: ffffffff8cb2d5a0 RDI: ffff88801ab90b30
RBP: ffffc9000cb1e530 R08: ffffffff8e1fdeef R09: 1ffffffff1c3fbdd
R10: dffffc0000000000 R11: fffffbfff1c3fbde R12: ffff88801ab90b30
R13: dffffc0000000000 R14: ffff88801ab90b50 R15: 1ffff92001963c90
FS:  00007f57331bf6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00003ae04776f000 CR3: 000000007c460000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 rcu_lock_release include/linux/rcupdate.h:355 [inline]
 rcu_read_unlock include/linux/rcupdate.h:824 [inline]
 tipc_sk_lookup+0x808/0x910 net/tipc/socket.c:3006
 tipc_sk_rcv+0x408/0x2be0 net/tipc/socket.c:2494
 tipc_node_xmit+0x212/0xf70 net/tipc/node.c:1703
 tipc_node_xmit_skb net/tipc/node.c:1768 [inline]
 tipc_node_distr_xmit+0x2d2/0x3f0 net/tipc/node.c:1783
 tipc_sk_rcv+0x2660/0x2be0 net/tipc/socket.c:2503
 tipc_node_xmit+0x212/0xf70 net/tipc/node.c:1703
 tipc_sk_push_backlog net/tipc/socket.c:1316 [inline]
 tipc_sk_filter_connect net/tipc/socket.c:2257 [inline]
 tipc_sk_filter_rcv+0x1c46/0x3300 net/tipc/socket.c:2366
 tipc_sk_enqueue net/tipc/socket.c:2447 [inline]
 tipc_sk_rcv+0x8ce/0x2be0 net/tipc/socket.c:2499
 tipc_node_xmit+0x212/0xf70 net/tipc/node.c:1703
 tipc_node_xmit_skb net/tipc/node.c:1768 [inline]
 tipc_node_distr_xmit+0x2d2/0x3f0 net/tipc/node.c:1783
 tipc_sk_backlog_rcv+0x1b8/0x270 net/tipc/socket.c:2414
 sk_backlog_rcv include/net/sock.h:1138 [inline]
 __release_sock+0x1e1/0x450 net/core/sock.c:2945
 release_sock+0x5b/0x1b0 net/core/sock.c:3511
 sockopt_release_sock net/core/sock.c:1065 [inline]
 sk_setsockopt+0x164c/0x28a0 net/core/sock.c:1543
 __sys_setsockopt+0x2f6/0x3d0 net/socket.c:2283
 __do_sys_setsockopt net/socket.c:2298 [inline]
 __se_sys_setsockopt net/socket.c:2295 [inline]
 __x64_sys_setsockopt+0xb1/0xc0 net/socket.c:2295
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f573239c819
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:00007f57331bf028 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 00007f5732616090 RCX: 00007f573239c819
RDX: 0000000000000021 RSI: 0000000000000001 RDI: 0000000000000003
RBP: 00007f5732432c91 R08: 0000000000000004 R09: 0000000000000000
R10: 00002000000001c0 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5732616128 R14: 00007f5732616090 R15: 00007ffff6946fe8
 </TASK>