syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P5927/2:b..l P7823/1:b..l
rcu: 	(detected by 1, t=10502 jiffies, g=15601, q=2403849 ncpus=2)
task:syz-executor    state:R  running task     stack:26440 pid:7823  tgid:7823  ppid:5831   task_flags:0x400000 flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1190/0x5de0 kernel/sched/core.c:6961
 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7288
 irqentry_exit+0x36/0x90 kernel/entry/common.c:197
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:rcu_read_unlock include/linux/rcupdate.h:869 [inline]
RIP: 0010:class_rcu_destructor include/linux/rcupdate.h:1155 [inline]
RIP: 0010:unwind_next_frame+0x3d9/0x20a0 arch/x86/kernel/unwind_orc.c:479
Code: b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 0f b6 04 02 84 c0 74 08 3c 03 0f 8e fc 14 00 00 41 c7 45 00 00 00 00 00 31 ed <e8> d2 88 28 0a 85 c0 0f 85 9b 06 00 00 48 c7 c7 e0 11 5c 8e 48 8d
RSP: 0018:ffffc90003687870 EFLAGS: 00000283
RAX: ffffc90003688001 RBX: ffffc90003687c20 RCX: ffffc90003688001
RDX: ffffc90003687c28 RSI: ffffc90003687bf0 RDI: ffffc900036878f0
RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000000
R10: ffffc900036878e0 R11: 00000000000116f8 R12: ffffc90003687930
R13: ffffc900036878e0 R14: ffffc90003687c20 R15: ffffc90003687914
 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 save_stack+0x160/0x1f0 mm/page_owner.c:156
 __reset_page_owner+0x84/0x1a0 mm/page_owner.c:308
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1395 [inline]
 __free_frozen_pages+0x7d5/0x10f0 mm/page_alloc.c:2895
 discard_slab mm/slub.c:2753 [inline]
 __put_partials+0x165/0x1c0 mm/slub.c:3218
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x4d/0x120 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:340
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4180 [inline]
 slab_alloc_node mm/slub.c:4229 [inline]
 __do_kmalloc_node mm/slub.c:4364 [inline]
 __kvmalloc_node_noprof+0x230/0x620 mm/slub.c:5052
 kvmalloc_array_node_noprof include/linux/slab.h:1065 [inline]
 alloc_fdtable+0x10b/0x2d0 fs/file.c:219
 expand_fdtable fs/file.c:259 [inline]
 expand_files+0x176/0xa60 fs/file.c:315
 ksys_dup3+0x113/0x370 fs/file.c:1412
 __do_sys_dup2 fs/file.c:1451 [inline]
 __se_sys_dup2 fs/file.c:1435 [inline]
 __x64_sys_dup2+0x82/0x460 fs/file.c:1435
 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: 0033:0x7f33cb38d8d7
RSP: 002b:00007ffcffa203d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000021
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f33cb38d8d7
RDX: 0000000000000000 RSI: 00000000000000f9 RDI: 0000000000000000
RBP: 00007f33cb5b2060 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000246 R12: 00007ffcffa20440
R13: 00007ffcffa20448 R14: 0000000000000009 R15: 0000000000000000
 </TASK>
task:kworker/0:5     state:R  running task     stack:25080 pid:5927  tgid:5927  ppid:2      task_flags:0x4208060 flags:0x00004000
Workqueue: mld mld_dad_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1190/0x5de0 kernel/sched/core.c:6961
 preempt_schedule_common+0x44/0xc0 kernel/sched/core.c:7145
 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
 __local_bh_enable_ip+0x107/0x120 kernel/softirq.c:414
 ipv6_get_lladdr+0x299/0x4f0 net/ipv6/addrconf.c:1942
 mld_newpack.isra.0+0x41d/0xa20 net/ipv6/mcast.c:1794
 add_grhead+0x299/0x340 net/ipv6/mcast.c:1891
 add_grec+0x11b5/0x1720 net/ipv6/mcast.c:2030
 mld_send_initial_cr+0x151/0x320 net/ipv6/mcast.c:2273
 mld_dad_work+0x32/0x1f0 net/ipv6/mcast.c:2299
 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3236
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: rcu_preempt kthread starved for 10298 jiffies! g15601 f0x2 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:27888 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1190/0x5de0 kernel/sched/core.c:6961
 __schedule_loop kernel/sched/core.c:7043 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:7058
 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2285
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x5d7/0x6f0 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:
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted 6.17.0-rc1-syzkaller-00199-gdfd4b508c8c6 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82
Code: 7c 62 02 c3 cc cc cc cc 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 d3 92 16 00 fb f4 <e9> 4c 0d 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffc90000197df8 EFLAGS: 000002c2
RAX: 00000000006abfcc RBX: 0000000000000001 RCX: ffffffff8b937c29
RDX: ffffed10170a6656 RSI: ffffffff8c162680 RDI: ffffffff819133c1
RBP: ffffed1003c56488 R08: 0000000000000000 R09: ffffed10170a6655
R10: ffff8880b85332ab R11: 0000000000000001 R12: 0000000000000001
R13: ffff88801e2b2440 R14: ffffffff90ab3b90 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8881247bc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f33cb5b2060 CR3: 000000001eec6000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:757
 default_idle_call+0x6d/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:190 [inline]
 do_idle+0x391/0x510 kernel/sched/idle.c:330
 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:428
 start_secondary+0x21d/0x2b0 arch/x86/kernel/smpboot.c:315
 common_startup_64+0x13e/0x148
 </TASK>