syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P11765/1:b..l P11768/3:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=41593, q=650 ncpus=2)
task:syz-executor    state:R  running task     stack:28712 pid:11768 tgid:11768 ppid:5828   task_flags:0x400040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5396 [inline]
 __schedule+0x116a/0x5de0 kernel/sched/core.c:6785
 preempt_schedule_common+0x44/0xc0 kernel/sched/core.c:6965
 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
 _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:391 [inline]
 filemap_map_pages+0xe2e/0x1680 mm/filemap.c:3757
 do_fault_around mm/memory.c:5568 [inline]
 do_read_fault mm/memory.c:5601 [inline]
 do_fault mm/memory.c:5744 [inline]
 do_pte_missing mm/memory.c:4251 [inline]
 handle_pte_fault mm/memory.c:6089 [inline]
 __handle_mm_fault+0x3b3b/0x5490 mm/memory.c:6232
 handle_mm_fault+0x589/0xd10 mm/memory.c:6401
 do_user_addr_fault+0x60c/0x1370 arch/x86/mm/fault.c:1336
 handle_page_fault arch/x86/mm/fault.c:1476 [inline]
 exc_page_fault+0x5c/0xb0 arch/x86/mm/fault.c:1532
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0033:0x7f2ec87182f0
RSP: 002b:00007fff72050198 EFLAGS: 00010286
RAX: ffffffffffffffff RBX: 00007fff720501a0 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 00007fff720501a0 RDI: 000055555685b808
RBP: 00007fff720505dc R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000012f
R13: 000000000000005f R14: 0000000000087cbb R15: 00007fff72050630
 </TASK>
task:syz.0.1485      state:R  running task     stack:27144 pid:11765 tgid:11764 ppid:5816   task_flags:0x400140 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5396 [inline]
 __schedule+0x116a/0x5de0 kernel/sched/core.c:6785
 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7108
 irqentry_exit+0x36/0x90 kernel/entry/common.c:307
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_acquire+0x62/0x350 kernel/locking/lockdep.c:5875
Code: 42 34 12 83 f8 07 0f 87 bc 02 00 00 89 c0 48 0f a3 05 42 8e 0f 0f 0f 82 74 02 00 00 8b 35 2a c0 0f 0f 85 f6 0f 85 8d 00 00 00 <48> 8b 44 24 30 65 48 2b 05 d9 41 34 12 0f 85 c7 02 00 00 48 83 c4
RSP: 0018:ffffc9001ecaf070 EFLAGS: 00000206
RAX: 0000000000000046 RBX: ffffffff8e5c4840 RCX: 00000000b49e3be8
RDX: 0000000000000000 RSI: ffffffff8ddf3a91 RDI: ffffffff8c1570a0
RBP: 0000000000000002 R08: 29ff72c3e22edc3e R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 rcu_read_lock include/linux/rcupdate.h:841 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1155 [inline]
 unwind_next_frame+0xd1/0x20a0 arch/x86/kernel/unwind_orc.c:479
 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 unpoison_slab_object mm/kasan/common.c:319 [inline]
 __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:345
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4148 [inline]
 slab_alloc_node mm/slub.c:4197 [inline]
 kmem_cache_alloc_noprof+0x1cb/0x3b0 mm/slub.c:4204
 __kernfs_new_node+0xd2/0x8e0 fs/kernfs/dir.c:637
 kernfs_new_node+0x13c/0x1e0 fs/kernfs/dir.c:713
 __kernfs_create_file+0x53/0x350 fs/kernfs/file.c:1039
 sysfs_add_file_mode_ns+0x207/0x3c0 fs/sysfs/file.c:319
 create_files fs/sysfs/group.c:76 [inline]
 internal_create_group+0x578/0xf30 fs/sysfs/group.c:183
 internal_create_groups+0x9d/0x150 fs/sysfs/group.c:223
 setup_port+0x404/0x1720 drivers/infiniband/core/sysfs.c:1247
 ib_setup_port_attrs+0x201/0x600 drivers/infiniband/core/sysfs.c:1433
 add_one_compat_dev+0x558/0x7d0 drivers/infiniband/core/device.c:968
 rdma_dev_init_net+0x2b1/0x530 drivers/infiniband/core/device.c:1184
 ops_init+0x1df/0x5f0 net/core/net_namespace.c:138
 setup_net+0x1ff/0x510 net/core/net_namespace.c:442
 copy_net_ns+0x2a6/0x5f0 net/core/net_namespace.c:574
 create_new_namespaces+0x3ea/0xa90 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0xc0/0x1f0 kernel/nsproxy.c:218
 ksys_unshare+0x45b/0xa40 kernel/fork.c:3121
 __do_sys_unshare kernel/fork.c:3192 [inline]
 __se_sys_unshare kernel/fork.c:3190 [inline]
 __x64_sys_unshare+0x31/0x40 kernel/fork.c:3190
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f458018e929
RSP: 002b:00007f458107d038 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007f45803b5fa0 RCX: 00007f458018e929
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000006a040000
RBP: 00007f4580210b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f45803b5fa0 R15: 00007ffe6ffeeae8
 </TASK>
rcu: rcu_preempt kthread starved for 10099 jiffies! g41593 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:28120 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5396 [inline]
 __schedule+0x116a/0x5de0 kernel/sched/core.c:6785
 __schedule_loop kernel/sched/core.c:6863 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:6878
 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2054
 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2256
 kthread+0x3c5/0x780 kernel/kthread.c:464
 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </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 UID: 0 PID: 0 Comm: swapper/1 Not tainted 6.16.0-rc1-syzkaller-00005-g488ef3560196 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82
Code: bb 72 02 e9 03 fb 02 00 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 23 50 2a 00 fb f4 <c3> cc cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffc90000197df8 EFLAGS: 000002c6
RAX: 0000000001f66237 RBX: 0000000000000001 RCX: ffffffff8b7fbc99
RDX: 0000000000000000 RSI: ffffffff8de18f75 RDI: ffffffff8c1570a0
RBP: ffffed1003c53488 R08: 0000000000000001 R09: ffffed10170a6645
R10: ffff8880b853322b R11: 0000000000000001 R12: 0000000000000001
R13: ffff88801e29a440 R14: ffffffff90a80c50 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888124854000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f07264e56c0 CR3: 0000000025af0000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:749
 default_idle_call+0x6d/0xb0 kernel/sched/idle.c:117
 cpuidle_idle_call kernel/sched/idle.c:185 [inline]
 do_idle+0x391/0x510 kernel/sched/idle.c:325
 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:423
 start_secondary+0x21d/0x2b0 arch/x86/kernel/smpboot.c:315
 common_startup_64+0x13e/0x148
 </TASK>