syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P5842/1:b..l P5841/1:b..l
rcu: 	(detected by 1, t=10502 jiffies, g=23653, q=394 ncpus=2)
task:syz-executor    state:R  running task     stack:21464 pid:5841  tgid:5841  ppid:5823   task_flags:0x400140 flags:0x20004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x16e2/0x4cd0 kernel/sched/core.c:6767
 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7090
 irqentry_exit+0x6f/0x90 kernel/entry/common.c:354
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:__rcu_read_unlock+0x6/0xe0 kernel/rcu/tree_plugin.h:431
Code: c1 03 38 c1 7c dc 48 89 df e8 a6 18 7a 00 eb d2 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 41 57 <41> 56 41 55 41 54 53 49 bf 00 00 00 00 00 fc ff df 65 48 8b 3c 25
RSP: 0018:ffffc9000411eee8 EFLAGS: 00000286
RAX: 09e6613ff146cc00 RBX: ffffffff909de801 RCX: 09e6613ff146cc00
RDX: 0000000000000003 RSI: ffffffff8d935a8d RDI: ffffffff8bc1d220
RBP: dffffc0000000000 R08: ffffc9000411fc10 R09: 0000000000000000
R10: ffffc9000411f018 R11: fffff52000823e05 R12: ffffc9000411fc20
R13: ffffc90004118000 R14: ffffc9000411efc8 R15: ffffffff817199f5
 rcu_read_unlock include/linux/rcupdate.h:873 [inline]
 class_rcu_destructor include/linux/rcupdate.h:1155 [inline]
 unwind_next_frame+0x19ae/0x2390 arch/x86/kernel/unwind_orc.c:680
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 save_stack+0xf7/0x1f0 mm/page_owner.c:156
 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:308
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1262 [inline]
 __free_frozen_pages+0xb0e/0xcd0 mm/page_alloc.c:2725
 __slab_free+0x326/0x400 mm/slub.c:4553
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_kmalloc+0x22/0xb0 mm/kasan/common.c:385
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __do_kmalloc_node mm/slub.c:4327 [inline]
 __kmalloc_node_noprof+0x276/0x4e0 mm/slub.c:4333
 kmalloc_node_noprof include/linux/slab.h:932 [inline]
 __vmalloc_area_node mm/vmalloc.c:3647 [inline]
 __vmalloc_node_range_noprof+0x51a/0x12c0 mm/vmalloc.c:3844
 __vmalloc_node_noprof mm/vmalloc.c:3907 [inline]
 vmalloc_noprof+0x79/0x90 mm/vmalloc.c:3940
 xt_compat_init_offsets+0xd3/0x1c0 net/netfilter/x_tables.c:733
 compat_table_info+0x99/0xa90 net/ipv6/netfilter/ip6_tables.c:950
 get_info net/ipv6/netfilter/ip6_tables.c:987 [inline]
 do_ip6t_get_ctl+0x80c/0x1180 net/ipv6/netfilter/ip6_tables.c:1668
 nf_getsockopt+0x26b/0x290 net/netfilter/nf_sockopt.c:116
 ipv6_getsockopt+0x1ed/0x290 net/ipv6/ipv6_sockglue.c:1493
 do_sock_getsockopt+0x35d/0x650 net/socket.c:2357
 __sys_getsockopt+0x128/0x1d0 net/socket.c:2386
 __do_compat_sys_socketcall net/compat.c:494 [inline]
 __se_compat_sys_socketcall net/compat.c:423 [inline]
 __ia32_compat_sys_socketcall+0x824/0x9c0 net/compat.c:423
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
 __do_fast_syscall_32+0xb4/0x110 arch/x86/entry/syscall_32.c:306
 do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:331
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf7f94539
RSP: 002b:00000000f757f650 EFLAGS: 00000206 ORIG_RAX: 0000000000000066
RAX: ffffffffffffffda RBX: 000000000000000f RCX: 00000000f757f688
RDX: 00000000f757f704 RSI: 00000000f757f708 RDI: 00000000f7422ff4
RBP: 00000000f7424b80 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
task:syz-executor    state:R  running task     stack:21384 pid:5842  tgid:5842  ppid:1      task_flags:0x400140 flags:0x20000006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x16e2/0x4cd0 kernel/sched/core.c:6767
 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7090
 irqentry_exit+0x6f/0x90 kernel/entry/common.c:354
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_acquire+0x175/0x360 kernel/locking/lockdep.c:5870
Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 6b 41 d7 10 <48> 3b 44 24 58 0f 85 f2 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e
RSP: 0018:ffffc9000405f298 EFLAGS: 00000206
RAX: e26533cbcc277900 RBX: 0000000000000000 RCX: e26533cbcc277900
RDX: 0000000000000000 RSI: ffffffff8d935a8d RDI: ffffffff8bc1d220
RBP: ffffffff817199f5 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: ffffffff817199f5 R12: 0000000000000002
R13: ffffffff8df3b860 R14: 0000000000000000 R15: 0000000000000246
 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+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 save_stack+0xf7/0x1f0 mm/page_owner.c:156
 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:308
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1262 [inline]
 __free_frozen_pages+0xb0e/0xcd0 mm/page_alloc.c:2725
 discard_slab mm/slub.c:2716 [inline]
 __put_partials+0x161/0x1c0 mm/slub.c:3185
 put_cpu_partial+0x17c/0x250 mm/slub.c:3260
 __slab_free+0x2f7/0x400 mm/slub.c:4512
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4147 [inline]
 slab_alloc_node mm/slub.c:4196 [inline]
 kmem_cache_alloc_noprof+0x1c1/0x3c0 mm/slub.c:4203
 alloc_empty_file+0x55/0x1d0 fs/file_table.c:234
 path_openat+0x107/0x3830 fs/namei.c:4025
 do_filp_open+0x1fa/0x410 fs/namei.c:4066
 do_sys_openat2+0x121/0x1c0 fs/open.c:1429
 do_sys_open fs/open.c:1444 [inline]
 __do_compat_sys_openat fs/open.c:1506 [inline]
 __se_compat_sys_openat fs/open.c:1504 [inline]
 __ia32_compat_sys_openat+0x131/0x160 fs/open.c:1504
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
 __do_fast_syscall_32+0xb4/0x110 arch/x86/entry/syscall_32.c:306
 do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:331
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf7fc7539
RSP: 002b:00000000f75afd50 EFLAGS: 00000206 ORIG_RAX: 0000000000000127
RAX: ffffffffffffffda RBX: 00000000ffffff9c RCX: 00000000f72d6b66
RDX: 0000000000098800 RSI: 0000000000000000 RDI: 00000000f7452ff4
RBP: 000000000000012d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
rcu: rcu_preempt kthread starved for 10287 jiffies! g23653 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:27304 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x16e2/0x4cd0 kernel/sched/core.c:6767
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6860
 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2046
 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2248
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
 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 6.15.0-rc4-syzkaller-00296-ge8ab83e34bdc #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/29/2025
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:81
Code: cc cc cc cc cc cc cc 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 03 fb 11 00 f3 0f 1e fa fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90000197de0 EFLAGS: 000002c6
RAX: 4dcdf414343db800 RBX: ffffffff81973f28 RCX: 4dcdf414343db800
RDX: 0000000000000001 RSI: ffffffff8d74aa91 RDI: ffffffff8bc1d220
RBP: ffffc90000197f20 R08: ffff8880b8932b5b R09: 1ffff1101712656b
R10: dffffc0000000000 R11: ffffed101712656c R12: ffffffff8f7ed970
R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff110038d9b40
FS:  0000000000000000(0000) GS:ffff8881261cb000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8efb4ce870 CR3: 000000007b612000 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:748
 default_idle_call+0x74/0xb0 kernel/sched/idle.c:117
 cpuidle_idle_call kernel/sched/idle.c:185 [inline]
 do_idle+0x1e8/0x510 kernel/sched/idle.c:325
 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:423
 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:315
 common_startup_64+0x13e/0x147
 </TASK>