syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P11194/1:b..l
rcu: 	(detected by 1, t=10502 jiffies, g=38209, q=341 ncpus=2)
task:syz.0.1196      state:R  running task     stack:26024 pid:11194 ppid:5787   flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7009
 irqentry_exit+0x67/0x70 kernel/entry/common.c:438
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:queue_work_on+0x187/0x1e0 kernel/workqueue.c:1840
Code: 4d 85 e4 75 16 e8 39 2c 2f 00 eb 15 e8 32 2c 2f 00 e8 4d 6a 18 09 4d 85 e4 74 ea e8 23 2c 2f 00 fb 48 c7 44 24 20 0e 36 e0 45 <48> b8 00 00 00 00 00 fc ff df 49 c7 44 05 00 00 00 00 00 66 41 c7
RSP: 0018:ffffc900049ef4c0 EFLAGS: 00000293
RAX: ffffffff8156636d RBX: 0000000000000000 RCX: ffff88807ac2da00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900049ef590 R08: ffffffff90da861f R09: 1ffffffff21b50c3
R10: dffffc0000000000 R11: fffffbfff21b50c4 R12: 0000000000000200
R13: 1ffff9200093de9c R14: 0000000000000000 R15: dffffc0000000001
 queue_work include/linux/workqueue.h:562 [inline]
 schedule_work include/linux/workqueue.h:623 [inline]
 __rhashtable_remove_fast_one include/linux/rhashtable.h:1069 [inline]
 __rhashtable_remove_fast include/linux/rhashtable.h:1093 [inline]
 rhltable_remove include/linux/rhashtable.h:1144 [inline]
 sctp_unhash_transport+0x110c/0x11c0 net/sctp/input.c:980
 sctp_association_free+0x699/0x7f0 net/sctp/associola.c:379
 sctp_cmd_delete_tcb net/sctp/sm_sideeffect.c:944 [inline]
 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1330 [inline]
 sctp_side_effects net/sctp/sm_sideeffect.c:1198 [inline]
 sctp_do_sm+0x3e64/0x59a0 net/sctp/sm_sideeffect.c:1169
 sctp_assoc_bh_rcv+0x3f2/0x630 net/sctp/associola.c:1052
 sctp_backlog_rcv+0x163/0x3e0 net/sctp/input.c:331
 sk_backlog_rcv include/net/sock.h:1129 [inline]
 __release_sock+0x1bd/0x430 net/core/sock.c:3010
 release_sock+0x5f/0x1c0 net/core/sock.c:3547
 sctp_close+0x6fb/0x900 net/sctp/socket.c:1536
 inet_release+0x13d/0x180 net/ipv4/af_inet.c:434
 __sock_release net/socket.c:659 [inline]
 sock_close+0xbd/0x230 net/socket.c:1421
 __fput+0x234/0x970 fs/file_table.c:384
 task_work_run+0x1ce/0x250 kernel/task_work.c:239
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0xf6/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f9ed338f6c9
RSP: 002b:00007ffcc0b83088 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007f9ed35e7da0 RCX: 00007f9ed338f6c9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f9ed35e7da0 R08: 00000000000253f4 R09: 00000019c0b8337f
R10: 00000000005d740c R11: 0000000000000246 R12: 00000000000b3609
R13: 00007ffcc0b83180 R14: ffffffffffffffff R15: 00007ffcc0b831a0
 </TASK>
rcu: rcu_preempt kthread starved for 10502 jiffies! g38209 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:27496 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: 0 Comm: swapper/1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
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 c3 64 39 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:ffffc90000187de0 EFLAGS: 000002c2
RAX: 56cc565b55fe4f00 RBX: ffffffff816187ab RCX: 56cc565b55fe4f00
RDX: 0000000000000001 RSI: ffffffff8aaabce0 RDI: ffffffff8afc6b00
RBP: ffffc90000187f20 R08: ffff8880b8f36b2b R09: 1ffff110171e6d65
R10: dffffc0000000000 R11: ffffed10171e6d66 R12: ffffffff8e4a8d68
R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff1100364e780
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c388196 CR3: 0000000064b10000 CR4: 00000000003506e0
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:753
 default_idle_call+0x6c/0xa0 kernel/sched/idle.c:97
 cpuidle_idle_call kernel/sched/idle.c:170 [inline]
 do_idle+0x1eb/0x510 kernel/sched/idle.c:282
 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:380
 start_secondary+0xee/0xf0 arch/x86/kernel/smpboot.c:323
 secondary_startup_64_no_verify+0x179/0x17b
 </TASK>