syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (2 ticks this GP) idle=8bcc/1/0x4000000000000000 softirq=16969/16969 fqs=0
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P5496/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=13245, q=778 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 5964 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:advance_sched+0x5a7/0xc90 net/sched/sch_taprio.c:970
Code: 48 bb ff ff ff ff ff ff ff 7f 49 bc 00 00 00 00 00 fc ff df eb 44 e8 08 7c 50 f8 49 bc 00 00 00 00 00 fc ff df 48 8b 44 24 48 <42> 80 3c 20 00 48 8b 5c 24 10 74 08 48 89 df e8 15 9c b6 f8 48 8b
RSP: 0018:ffffc90000a08c70 EFLAGS: 00000006
RAX: 1ffff1100b73fc2a RBX: 0000000000000000 RCX: ffff88802ebd9e80
RDX: 0000000000010000 RSI: 0000000000000400 RDI: 0000000000000000
RBP: 1ffff1100b73fc00 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff5200014117c R12: dffffc0000000000
R13: ffff88805b9fe0c0 R14: ffff88805b9fe000 R15: 0000000000000000
FS:  000055556c94b500(0000) GS:ffff888125f1f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055556dfb45c8 CR3: 0000000030282000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 __run_hrtimer kernel/time/hrtimer.c:1777 [inline]
 __hrtimer_run_queues+0x51c/0xc30 kernel/time/hrtimer.c:1841
 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline]
 __sysvec_apic_timer_interrupt+0x102/0x3e0 arch/x86/kernel/apic/apic.c:1062
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
 sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1056
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:deref_stack_regs arch/x86/kernel/unwind_orc.c:438 [inline]
RIP: 0010:unwind_next_frame+0x108a/0x23d0 arch/x86/kernel/unwind_orc.c:611
Code: 3c 28 00 4c 8b 64 24 10 74 08 4c 89 e7 e8 ae 0b b3 00 49 89 1c 24 49 8d bf 98 00 00 00 e8 7e 1f 00 00 48 89 c3 48 8b 44 24 58 <80> 3c 28 00 4c 8b 7c 24 78 4c 8b 64 24 48 74 08 4c 89 ff e8 7e 0b
RSP: 0018:ffffc90003cff8b8 EFLAGS: 00000246
RAX: 1ffff9200079ff38 RBX: 00007ffc476d1058 RCX: 1ffff9200079ff01
RDX: ffffffff900cc67e RSI: 0000000000000003 RDI: ffffc90003cfffe0
RBP: dffffc0000000000 R08: 0000000000000022 R09: ffffffff8df41aa0
R10: ffffc90003cff9d8 R11: ffffffff81acf3d0 R12: ffffc90003cff9d0
R13: ffffc90003cff990 R14: ffffc90003cff988 R15: ffffc90003cfff48
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 ref_tracker_free+0xef/0x7d0 lib/ref_tracker.c:307
 __netns_tracker_free include/net/net_namespace.h:379 [inline]
 put_net_track include/net/net_namespace.h:394 [inline]
 __sk_destruct+0x3c7/0x880 net/core/sock.c:2379
 sock_put include/net/sock.h:1998 [inline]
 unix_release_sock+0xa36/0xc70 net/unix/af_unix.c:732
 unix_release+0x92/0xd0 net/unix/af_unix.c:1184
 __sock_release net/socket.c:662 [inline]
 sock_close+0xc3/0x240 net/socket.c:1455
 __fput+0x44c/0xa70 fs/file_table.c:468
 fput_close_sync+0x113/0x220 fs/file_table.c:573
 __do_sys_close fs/open.c:1573 [inline]
 __se_sys_close fs/open.c:1558 [inline]
 __x64_sys_close+0x7f/0x110 fs/open.c:1558
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff05e38eea7
Code: 44 00 00 48 c7 c2 a8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff eb bc 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 a8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffc476d1058 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 00007ff05e38eea7
RDX: 0000000000000000 RSI: 0000000000008933 RDI: 0000000000000005
RBP: 00007ffc476d1060 R08: 0000000000000005 R09: 006e616c765f3168
R10: 0000000000000021 R11: 0000000000000246 R12: 0000000000000003
R13: 00007ff05f114620 R14: 0000000000000006 R15: 0000000000000000
 </TASK>
task:dhcpcd          state:R  running task     stack:21240 pid:5496  tgid:5496  ppid:5495   task_flags:0x400140 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x149b/0x4fd0 kernel/sched/core.c:6863
 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7190
 irqentry_exit+0x5e3/0x670 kernel/entry/common.c:216
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:228 [inline]
RIP: 0010:unwind_next_frame+0x214/0x23d0 arch/x86/kernel/unwind_orc.c:510
Code: ef 08 8b 15 7e 04 27 0c 8d 42 ff 44 39 f8 0f 86 78 04 00 00 44 89 f8 4c 8d 2c 85 a0 1e c2 90 4c 89 e8 48 c1 e8 03 0f b6 04 28 <84> c0 48 89 eb 0f 85 2c 1c 00 00 45 8b 6d 00 44 89 f8 ff c0 48 8d
RSP: 0018:ffffc90003a97278 EFLAGS: 00000a03
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000080000000
RDX: 00000000000a5d72 RSI: ffffffff8bc08340 RDI: ffffffff8bc08300
RBP: dffffc0000000000 R08: ffffffff8173fd65 R09: ffffffff8df41aa0
R10: ffffc90003a97398 R11: ffffffff81acf3d0 R12: ffffffff82114d23
R13: ffffffff90c663d4 R14: ffffc90003a97348 R15: 000000000001114d
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 unpoison_slab_object mm/kasan/common.c:340 [inline]
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4953 [inline]
 slab_alloc_node mm/slub.c:5263 [inline]
 kmem_cache_alloc_noprof+0x37d/0x710 mm/slub.c:5270
 anon_vma_chain_alloc mm/rmap.c:141 [inline]
 anon_vma_clone+0xb8/0x4f0 mm/rmap.c:287
 anon_vma_fork+0x79/0x500 mm/rmap.c:350
 dup_mmap+0x954/0x1b80 mm/mmap.c:1790
 dup_mm kernel/fork.c:1529 [inline]
 copy_mm+0x13c/0x4b0 kernel/fork.c:1581
 copy_process+0x165d/0x3950 kernel/fork.c:2221
 kernel_clone+0x21e/0x820 kernel/fork.c:2651
 __do_sys_clone kernel/fork.c:2792 [inline]
 __se_sys_clone kernel/fork.c:2776 [inline]
 __x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2776
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f35f176d636
RSP: 002b:00007fff9d59f150 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007fff9d59f158 RCX: 00007f35f176d636
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 00007fff9d5bf6a0 R08: 0000000000000000 R09: 0000000000000001
R10: 00007f35f1699a10 R11: 0000000000000246 R12: 00007fff9d59f290
R13: 0000000000000000 R14: 0000000000000000 R15: 0000560009e66ac0
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g13245 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=4320
rcu: rcu_preempt kthread starved for 10502 jiffies! g13245 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27480 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x149b/0x4fd0 kernel/sched/core.c:6863
 __schedule_loop kernel/sched/core.c:6945 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6960
 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>