syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (1 GPs behind) idle=de44/1/0x4000000000000000 softirq=176400/176401 fqs=18
rcu: 	(detected by 0, t=10505 jiffies, g=187097, q=2349 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 23126 Comm: kworker/u8:21 Not tainted 6.14.0-rc5-syzkaller-00013-g99fa936e8e4f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Workqueue: ib-unreg-wq ib_unregister_work
RIP: 0010:debug_spin_unlock kernel/locking/spinlock_debug.c:105 [inline]
RIP: 0010:do_raw_spin_unlock+0x102/0x230 kernel/locking/spinlock_debug.c:141
Code: 8e ff 00 00 00 65 8b 05 f8 b6 6c 7e 39 43 08 0f 85 b7 00 00 00 48 b8 00 00 00 00 00 fc ff df 4c 89 e2 48 c1 ea 03 80 3c 02 00 <0f> 85 f8 00 00 00 48 89 ea 48 c7 43 10 ff ff ff ff 48 b8 00 00 00
RSP: 0018:ffffc90000a18d50 EFLAGS: 00000046
RAX: dffffc0000000000 RBX: ffff88804eea42e8 RCX: ffffffff819721c3
RDX: 1ffff11009dd485f RSI: 0000000000000004 RDI: ffff88804eea42e8
RBP: ffff88804eea42f0 R08: 0000000000000000 R09: ffffed1009dd485d
R10: ffff88804eea42eb R11: 0000000000000004 R12: ffff88804eea42f8
R13: ffff888028028800 R14: ffff88804eea4340 R15: ffff88805b279000
FS:  0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c2cba9e CR3: 000000003e338000 CR4: 00000000003526f0
DR0: 0000000000000002 DR1: fffffffffffffffb DR2: 0000000000010001
DR3: 0000000000000004 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 __raw_spin_unlock include/linux/spinlock_api_smp.h:142 [inline]
 _raw_spin_unlock+0x1e/0x50 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:391 [inline]
 advance_sched+0x611/0xc60 net/sched/sch_taprio.c:981
 __run_hrtimer kernel/time/hrtimer.c:1801 [inline]
 __hrtimer_run_queues+0x20a/0xae0 kernel/time/hrtimer.c:1865
 hrtimer_interrupt+0x392/0x8e0 kernel/time/hrtimer.c:1927
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline]
 __sysvec_apic_timer_interrupt+0x10f/0x400 arch/x86/kernel/apic/apic.c:1055
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
 sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1049
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:preempt_count_sub+0xc/0x160 kernel/sched/core.c:5879
Code: 1e fa 48 c7 c7 e0 0e 83 93 e9 e0 6c 66 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 c7 c0 a0 d8 8b 9a 53 <89> fb 48 ba 00 00 00 00 00 fc ff df 48 89 c1 83 e0 07 48 c1 e9 03
RSP: 0018:ffffc9000b6ff5a8 EFLAGS: 00000287
RAX: ffffffff9a8bd8a0 RBX: ffffc9000b6ffb58 RCX: ffffc9000b700001
RDX: ffffc9000b6ffb60 RSI: ffffc9000b6ffb28 RDI: 0000000000000001
RBP: ffffc9000b6f8000 R08: ffffc9000b6ff65c R09: ffffffff91759344
R10: ffffc9000b6ff628 R11: 0000000000076883 R12: ffffc9000b6ff678
R13: ffffc9000b6ff628 R14: ffffc9000b6ffb58 R15: ffffc9000b6ffb50
 unwind_next_frame+0xe5d/0x20c0 arch/x86/kernel/unwind_orc.c:672
 arch_stack_walk+0x95/0x100 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x95/0xd0 kernel/stacktrace.c:122
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_record_aux_stack+0xb8/0xd0 mm/kasan/generic.c:548
 __call_rcu_common.constprop.0+0x9a/0x870 kernel/rcu/tree.c:3065
 kernfs_put.part.0+0x176/0x3a0 fs/kernfs/dir.c:578
 kernfs_put+0x47/0x50 fs/kernfs/dir.c:557
 kernfs_remove_by_name_ns+0xbc/0x130 fs/kernfs/dir.c:1696
 kernfs_remove_by_name include/linux/kernfs.h:625 [inline]
 remove_files+0x96/0x1c0 fs/sysfs/group.c:28
 sysfs_remove_group+0x8b/0x180 fs/sysfs/group.c:322
 sysfs_remove_groups fs/sysfs/group.c:346 [inline]
 sysfs_remove_groups+0x60/0xa0 fs/sysfs/group.c:338
 destroy_gid_attrs drivers/infiniband/core/sysfs.c:1193 [inline]
 ib_free_port_attrs+0x278/0x490 drivers/infiniband/core/sysfs.c:1418
 remove_one_compat_dev drivers/infiniband/core/device.c:992 [inline]
 remove_compat_devs drivers/infiniband/core/device.c:1004 [inline]
 disable_device+0x1e1/0x280 drivers/infiniband/core/device.c:1286
 __ib_unregister_device+0x2b4/0x480 drivers/infiniband/core/device.c:1502
 ib_unregister_work+0x19/0x30 drivers/infiniband/core/device.c:1614
 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf00 kernel/workqueue.c:3400
 kthread+0x3af/0x750 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
rcu: rcu_preempt kthread starved for 10415 jiffies! g187097 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R  running task     stack:27456 pid:17    tgid:17    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5378 [inline]
 __schedule+0xf43/0x5890 kernel/sched/core.c:6765
 __schedule_loop kernel/sched/core.c:6842 [inline]
 schedule+0xe7/0x350 kernel/sched/core.c:6857
 schedule_timeout+0x124/0x280 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1eb/0xb00 kernel/rcu/tree.c:2024
 rcu_gp_kthread+0x271/0x380 kernel/rcu/tree.c:2226
 kthread+0x3af/0x750 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 2916 Comm: syz.2.7845 Not tainted 6.14.0-rc5-syzkaller-00013-g99fa936e8e4f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline]
RIP: 0010:smp_call_function_many_cond+0x4c6/0x12c0 kernel/smp.c:885
Code: 0c 00 85 ed 74 4d 48 b8 00 00 00 00 00 fc ff df 4d 89 fc 4c 89 fd 49 c1 ec 03 83 e5 07 49 01 c4 83 c5 03 e8 7c 0e 0c 00 f3 90 <41> 0f b6 04 24 40 38 c5 7c 08 84 c0 0f 85 e8 0b 00 00 8b 43 08 31
RSP: 0018:ffffc9000448f820 EFLAGS: 00000293
RAX: 0000000000000000 RBX: ffff8880b8744a80 RCX: ffffffff81add36a
RDX: ffff8880788fc880 RSI: ffffffff81add344 RDI: 0000000000000005
RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: ffffed10170e8951
R13: 0000000000000001 R14: ffff8880b863fe80 R15: ffff8880b8744a88
FS:  0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff307aef19c CR3: 0000000061294000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 </IRQ>
 <TASK>
 on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1052
 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline]
 flush_tlb_multi arch/x86/mm/tlb.c:966 [inline]
 flush_tlb_mm_range+0x271/0x4a0 arch/x86/mm/tlb.c:1054
 tlb_flush arch/x86/include/asm/tlb.h:20 [inline]
 tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:481 [inline]
 tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:471 [inline]
 tlb_flush_mmu mm/mmu_gather.c:395 [inline]
 tlb_finish_mmu+0x3c9/0x7b0 mm/mmu_gather.c:488
 exit_mmap+0x40e/0xba0 mm/mmap.c:1297
 __mmput+0x12a/0x410 kernel/fork.c:1356
 mmput+0x62/0x70 kernel/fork.c:1378
 exit_mm kernel/exit.c:570 [inline]
 do_exit+0x9ba/0x2d70 kernel/exit.c:925
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1087
 get_signal+0x24ed/0x26c0 kernel/signal.c:3036
 arch_do_signal_or_restart+0x90/0x7e0 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x150/0x2a0 kernel/entry/common.c:218
 do_syscall_64+0xda/0x250 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7efd6778d169
Code: Unable to access opcode bytes at 0x7efd6778d13f.
RSP: 002b:00007fff10772cd8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffdfc RBX: 0000000000248c88 RCX: 00007efd6778d169
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007efd679a5fac
RBP: 0000000000000032 R08: 00007efd68539000 R09: 0000000110772fcf
R10: 00007fff10772dd0 R11: 0000000000000246 R12: 00007efd679a5fac
R13: 00007fff10772dd0 R14: 0000000000248cba R15: 00007fff10772df0
 </TASK>