syzbot

rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (10500 ticks this GP) idle=674c/1/0x4000000000000000 softirq=11708/11708 fqs=0
rcu: 	(t=10500 jiffies g=11901 q=112 ncpus=2)
rcu: rcu_preempt kthread timer wakeup didn't happen for 10499 jiffies! g11901 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=6389
rcu: rcu_preempt kthread starved for 10500 jiffies! g11901 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:27752 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:
CPU: 1 PID: 7703 Comm: syz-executor100 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:check_preemption_disabled+0x18/0x110 lib/smp_processor_id.c:14
Code: 20 70 fc 8a eb 0c 66 2e 0f 1f 84 00 00 00 00 00 66 90 55 41 57 41 56 53 48 83 ec 10 65 48 8b 04 25 28 00 00 00 48 89 44 24 08 <65> 8b 05 ad ab 95 75 65 8b 0d a2 ab 95 75 f7 c1 ff ff ff 7f 74 1f
RSP: 0018:ffffc900051762e8 EFLAGS: 00000286
RAX: 04170ac2e1aff100 RBX: 0000000000000000 RCX: ffff88802c799e00
RDX: ffff88802c799e00 RSI: ffffffff8afc7020 RDI: ffffffff8afc6fe0
RBP: 0000000000000057 R08: dffffc0000000000 R09: 1ffffffff21b4aa0
R10: dffffc0000000000 R11: fffffbfff21b4aa1 R12: ffff88802c6a0000
R13: dffffc0000000000 R14: 0000000000000001 R15: dffffc0000000000
FS:  00007efcb5f4a6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007efcb5f4ad58 CR3: 0000000024a00000 CR4: 00000000003506e0
Call Trace:
 <TASK>
 rcu_dynticks_curr_cpu_in_eqs include/linux/context_tracking.h:122 [inline]
 rcu_is_watching+0x15/0xb0 kernel/rcu/tree.c:700
 rcu_read_lock_held_common kernel/rcu/update.c:108 [inline]
 rcu_read_lock_held+0x15/0x40 kernel/rcu/update.c:348
 net_generic+0x101/0x240 include/net/netns/generic.h:46
 tipc_sk_lookup+0xaa/0x910 net/tipc/socket.c:3000
 tipc_sk_rcv+0x3fa/0x2b80 net/tipc/socket.c:2495
 tipc_node_xmit+0x1e4/0xee0 net/tipc/node.c:1703
 tipc_node_xmit_skb net/tipc/node.c:1768 [inline]
 tipc_node_distr_xmit+0x29e/0x3b0 net/tipc/node.c:1783
 tipc_sk_rcv+0x261b/0x2b80 net/tipc/socket.c:2504
 tipc_node_xmit+0x1e4/0xee0 net/tipc/node.c:1703
 tipc_sk_push_backlog+0x4ef/0x900 net/tipc/socket.c:1317
 tipc_sk_conn_proto_rcv net/tipc/socket.c:1371 [inline]
 tipc_sk_proto_rcv+0x8c3/0x16f0 net/tipc/socket.c:2161
 tipc_sk_filter_rcv+0x2df1/0x3030 net/tipc/socket.c:2355
 tipc_sk_enqueue net/tipc/socket.c:2448 [inline]
 tipc_sk_rcv+0x8a6/0x2b80 net/tipc/socket.c:2500
 tipc_node_xmit+0x1e4/0xee0 net/tipc/node.c:1703
 tipc_node_xmit_skb net/tipc/node.c:1768 [inline]
 tipc_node_distr_xmit+0x29e/0x3b0 net/tipc/node.c:1783
 tipc_sk_backlog_rcv+0x1a2/0x230 net/tipc/socket.c:2415
 sk_backlog_rcv include/net/sock.h:1123 [inline]
 __release_sock+0x1bd/0x430 net/core/sock.c:3005
 release_sock+0x5f/0x1c0 net/core/sock.c:3542
 sk_setsockopt+0x1d02/0x29d0 net/core/sock.c:-1
 do_sock_setsockopt+0x11b/0x1a0 net/socket.c:2318
 __sys_setsockopt net/socket.c:2345 [inline]
 __do_sys_setsockopt net/socket.c:2354 [inline]
 __se_sys_setsockopt net/socket.c:2351 [inline]
 __x64_sys_setsockopt+0x184/0x200 net/socket.c:2351
 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: 0033:0x7efcb5faa3e9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 51 18 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007efcb5f4a218 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 00007efcb5f4a6c0 RCX: 00007efcb5faa3e9
RDX: 0000000000000021 RSI: 0000000000000001 RDI: 0000000000000003
RBP: 00007efcb6034338 R08: 0000000000000004 R09: 0000000000000000
R10: 0000200000000540 R11: 0000000000000246 R12: 00002000000002c0
R13: 00007efcb6034330 R14: 00007efcb603433c R15: 0000200000000004
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 7702 Comm: syz-executor100 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:434 [inline]
RIP: 0010:__pv_queued_spin_lock_slowpath+0x532/0x9d0 kernel/locking/qspinlock.c:511
Code: 00 41 c6 45 00 00 48 8b 44 24 10 42 0f b6 04 38 84 c0 0f 85 1b 01 00 00 48 8b 44 24 08 c6 00 01 41 bd 00 80 ff ff eb 07 f3 90 <41> ff c5 74 47 43 0f b6 04 3e 84 c0 75 2b 80 3b 00 75 eb 48 89 df
RSP: 0018:ffffc9000b27f820 EFLAGS: 00000206
RAX: 0000000000000000 RBX: ffff88807960d858 RCX: ffff88802c798000
RDX: 0000000000000000 RSI: ffffffff8aaaba20 RDI: ffffffff8afc7040
RBP: ffffc9000b27f910 R08: ffffffff90da55cf R09: 1ffffffff21b4ab9
R10: dffffc0000000000 R11: fffffbfff21b4aba R12: 1ffff110171c0001
R13: 00000000ffffb668 R14: 1ffff1100f2c1b0b R15: dffffc0000000000
FS:  00007efcb5f6b6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000000 CR3: 0000000024a00000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 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_bh include/linux/spinlock.h:356 [inline]
 lock_sock_nested+0x6a/0x100 net/core/sock.c:3530
 lock_sock include/net/sock.h:1731 [inline]
 tipc_sendstream+0x47/0x70 net/tipc/socket.c:1550
 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: 0033:0x7efcb5faa3e9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 51 18 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007efcb5f6b218 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 00007efcb5faa3e9
RDX: 0000000000000000 RSI: 00002000000002c0 RDI: 0000000000000004
RBP: 00007efcb6034328 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00002000000002c0
R13: 00007efcb6034320 R14: 00007efcb603432c R15: 0000200000000004
 </TASK>
CPU: 1 PID: 7703 Comm: syz-executor100 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:check_preemption_disabled+0x18/0x110 lib/smp_processor_id.c:14
Code: 20 70 fc 8a eb 0c 66 2e 0f 1f 84 00 00 00 00 00 66 90 55 41 57 41 56 53 48 83 ec 10 65 48 8b 04 25 28 00 00 00 48 89 44 24 08 <65> 8b 05 ad ab 95 75 65 8b 0d a2 ab 95 75 f7 c1 ff ff ff 7f 74 1f
RSP: 0018:ffffc900051762e8 EFLAGS: 00000286
RAX: 04170ac2e1aff100 RBX: 0000000000000000 RCX: ffff88802c799e00
RDX: ffff88802c799e00 RSI: ffffffff8afc7020 RDI: ffffffff8afc6fe0
RBP: 0000000000000057 R08: dffffc0000000000 R09: 1ffffffff21b4aa0
R10: dffffc0000000000 R11: fffffbfff21b4aa1 R12: ffff88802c6a0000
R13: dffffc0000000000 R14: 0000000000000001 R15: dffffc0000000000
FS:  00007efcb5f4a6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007efcb5f4ad58 CR3: 0000000024a00000 CR4: 00000000003506e0
Call Trace:
 <TASK>
 rcu_dynticks_curr_cpu_in_eqs include/linux/context_tracking.h:122 [inline]
 rcu_is_watching+0x15/0xb0 kernel/rcu/tree.c:700
 rcu_read_lock_held_common kernel/rcu/update.c:108 [inline]
 rcu_read_lock_held+0x15/0x40 kernel/rcu/update.c:348
 net_generic+0x101/0x240 include/net/netns/generic.h:46
 tipc_sk_lookup+0xaa/0x910 net/tipc/socket.c:3000
 tipc_sk_rcv+0x3fa/0x2b80 net/tipc/socket.c:2495
 tipc_node_xmit+0x1e4/0xee0 net/tipc/node.c:1703
 tipc_node_xmit_skb net/tipc/node.c:1768 [inline]
 tipc_node_distr_xmit+0x29e/0x3b0 net/tipc/node.c:1783
 tipc_sk_rcv+0x261b/0x2b80 net/tipc/socket.c:2504
 tipc_node_xmit+0x1e4/0xee0 net/tipc/node.c:1703
 tipc_sk_push_backlog+0x4ef/0x900 net/tipc/socket.c:1317
 tipc_sk_conn_proto_rcv net/tipc/socket.c:1371 [inline]
 tipc_sk_proto_rcv+0x8c3/0x16f0 net/tipc/socket.c:2161
 tipc_sk_filter_rcv+0x2df1/0x3030 net/tipc/socket.c:2355
 tipc_sk_enqueue net/tipc/socket.c:2448 [inline]
 tipc_sk_rcv+0x8a6/0x2b80 net/tipc/socket.c:2500
 tipc_node_xmit+0x1e4/0xee0 net/tipc/node.c:1703
 tipc_node_xmit_skb net/tipc/node.c:1768 [inline]
 tipc_node_distr_xmit+0x29e/0x3b0 net/tipc/node.c:1783
 tipc_sk_backlog_rcv+0x1a2/0x230 net/tipc/socket.c:2415
 sk_backlog_rcv include/net/sock.h:1123 [inline]
 __release_sock+0x1bd/0x430 net/core/sock.c:3005
 release_sock+0x5f/0x1c0 net/core/sock.c:3542
 sk_setsockopt+0x1d02/0x29d0 net/core/sock.c:-1
 do_sock_setsockopt+0x11b/0x1a0 net/socket.c:2318
 __sys_setsockopt net/socket.c:2345 [inline]
 __do_sys_setsockopt net/socket.c:2354 [inline]
 __se_sys_setsockopt net/socket.c:2351 [inline]
 __x64_sys_setsockopt+0x184/0x200 net/socket.c:2351
 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: 0033:0x7efcb5faa3e9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 51 18 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007efcb5f4a218 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 00007efcb5f4a6c0 RCX: 00007efcb5faa3e9
RDX: 0000000000000021 RSI: 0000000000000001 RDI: 0000000000000003
RBP: 00007efcb6034338 R08: 0000000000000004 R09: 0000000000000000
R10: 0000200000000540 R11: 0000000000000246 R12: 00002000000002c0
R13: 00007efcb6034330 R14: 00007efcb603433c R15: 0000200000000004
 </TASK>