==================================================================
BUG: KASAN: slab-use-after-free in fib_rules_lookup+0x15e/0xeb0 net/core/fib_rules.c:321
Read of size 8 at addr ffff8880264fbd80 by task pool_workqueue_/3

CPU: 1 UID: 0 PID: 3 Comm: pool_workqueue_ Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
 <IRQ>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 fib_rules_lookup+0x15e/0xeb0 net/core/fib_rules.c:321
 __fib_lookup+0x106/0x210 net/ipv4/fib_rules.c:96
 ip_route_output_key_hash_rcu+0x294/0x2720 net/ipv4/route.c:2811
 ip_route_output_key_hash+0x18d/0x2a0 net/ipv4/route.c:2702
 icmp_route_lookup+0x50a/0xb50 net/ipv4/icmp.c:520
 __icmp_send+0x1010/0x1710 net/ipv4/icmp.c:958
 ipv4_send_dest_unreach net/ipv4/route.c:1253 [inline]
 ipv4_link_failure+0x64d/0xa50 net/ipv4/route.c:1260
 dst_link_failure include/net/dst.h:438 [inline]
 arp_error_report+0x118/0x160 net/ipv4/arp.c:296
 neigh_invalidate+0x243/0x470 net/core/neighbour.c:1077
 neigh_timer_handler+0xc01/0x12b0 net/core/neighbour.c:1169
 call_timer_fn+0x192/0x5e0 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1799 [inline]
 __run_timers kernel/time/timer.c:2374 [inline]
 __run_timer_base+0x652/0x8b0 kernel/time/timer.c:2386
 run_timer_base kernel/time/timer.c:2395 [inline]
 run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2405
 handle_softirqs+0x225/0x840 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0xca/0x220 kernel/softirq.c:735
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1061
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:finish_task_switch+0x41a/0xbc0 kernel/sched/core.c:5245
Code: 03 00 00 41 c7 84 24 e0 0d 00 00 00 00 00 00 0f 1f 44 00 00 49 83 c4 48 4c 89 e7 e8 f0 c5 13 0a e8 6b dd 38 00 fb 4c 8b 65 c8 <49> 8d bc 24 c8 16 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0
RSP: 0018:ffffc90000087940 EFLAGS: 00000202
RAX: 000000000000313b RBX: ffff8880b873be60 RCX: 0000000080000001
RDX: 0000000000000006 RSI: ffffffff8dfad1b9 RDI: ffffffff8c2886a0
RBP: ffffc90000087990 R08: ffffffff902fd2f7 R09: 1ffffffff205fa5e
R10: dffffc0000000000 R11: fffffbfff205fa5f R12: ffff88801d699f00
R13: ffff8880b873be28 R14: dffffc0000000000 R15: 1ffff110170e77cc
 context_switch kernel/sched/core.c:5391 [inline]
 __schedule+0x1848/0x57a0 kernel/sched/core.c:7189
 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7513
 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline]
 irqentry_exit+0x14f/0x8e0 kernel/entry/common.c:164
 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:check_kcov_mode kernel/kcov.c:185 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x30/0x70 kernel/kcov.c:217
Code: 04 24 65 48 8b 0d c8 af 72 11 65 8b 15 e9 af 72 11 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 ec 16 00 00 00 74 2c <8b> 91 c8 16 00 00 83 fa 02 75 21 48 8b 91 d0 16 00 00 48 8b 32 48
RSP: 0018:ffffc90000087cd0 EFLAGS: 00000246
RAX: ffffffff818e9d2d RBX: 1ffff11006b25f00 RCX: ffff88801d699f00
RDX: 0000000000000000 RSI: ffffffff8c288680 RDI: ffff88807a975890
RBP: ffff88803592f808 R08: ffffffff902fd2f7 R09: 1ffffffff205fa5e
R10: dffffc0000000000 R11: fffffbfff205fa5f R12: 1ffff1100f52eb01
R13: ffff88807a975890 R14: ffff88803592f800 R15: dffffc0000000000
 pwq_release_workfn+0x1ed/0x880 kernel/workqueue.c:5209
 kthread_worker_fn+0x4eb/0xb20 kernel/kthread.c:1025
 kthread+0x389/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 5636:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5296 [inline]
 __kmalloc_node_track_caller_noprof+0x4d7/0x7b0 mm/slub.c:5408
 kmemdup_noprof+0x2b/0x70 mm/util.c:138
 kmemdup_noprof include/linux/fortify-string.h:763 [inline]
 fib_rules_register+0x2f/0x400 net/core/fib_rules.c:170
 fib4_rules_init+0x21/0x160 net/ipv4/fib_rules.c:508
 ip_fib_net_init net/ipv4/fib_frontend.c:1578 [inline]
 fib_net_init+0x17a/0x3e0 net/ipv4/fib_frontend.c:1628
 ops_init+0x35d/0x5d0 net/core/net_namespace.c:137
 setup_net+0x118/0x350 net/core/net_namespace.c:446
 copy_net_ns+0x4f9/0x720 net/core/net_namespace.c:579
 create_new_namespaces+0x3f0/0x6b0 kernel/nsproxy.c:132
 unshare_nsproxy_namespaces+0x149/0x190 kernel/nsproxy.c:234
 ksys_unshare+0x57d/0xa00 kernel/fork.c:3242
 __do_sys_unshare kernel/fork.c:3316 [inline]
 __se_sys_unshare kernel/fork.c:3314 [inline]
 __x64_sys_unshare+0x38/0x50 kernel/fork.c:3314
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 23:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2689 [inline]
 __rcu_free_sheaf_prepare+0x12d/0x2a0 mm/slub.c:2940
 rcu_free_sheaf+0x31/0x200 mm/slub.c:5850
 rcu_do_batch kernel/rcu/tree.c:2617 [inline]
 rcu_core+0x78b/0x10a0 kernel/rcu/tree.c:2869
 handle_softirqs+0x225/0x840 kernel/softirq.c:622
 run_ksoftirqd+0x36/0x60 kernel/softirq.c:1076
 smpboot_thread_fn+0x57c/0xa80 kernel/smpboot.c:160
 kthread+0x389/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff8880264fbd00
 which belongs to the cache kmalloc-192 of size 192
The buggy address is located 128 bytes inside of
 freed 192-byte region [ffff8880264fbd00, ffff8880264fbdc0)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x264fb
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000000 ffff88813fe163c0 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 5099297973, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x22d/0x280 mm/page_alloc.c:1853
 prep_new_page mm/page_alloc.c:1861 [inline]
 get_page_from_freelist+0x24ae/0x2530 mm/page_alloc.c:3941
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5221
 alloc_slab_page mm/slub.c:3278 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3467
 new_slab mm/slub.c:3525 [inline]
 refill_objects+0x336/0x3d0 mm/slub.c:7272
 refill_sheaf mm/slub.c:2816 [inline]
 __pcs_replace_empty_main+0x320/0x720 mm/slub.c:4652
 alloc_from_pcs mm/slub.c:4750 [inline]
 slab_alloc_node mm/slub.c:4884 [inline]
 __kmalloc_cache_noprof+0x388/0x660 mm/slub.c:5415
 kmalloc_noprof include/linux/slab.h:950 [inline]
 kzalloc_noprof include/linux/slab.h:1188 [inline]
 call_usermodehelper_setup+0x8e/0x270 kernel/umh.c:362
 kobject_uevent_env+0x662/0x9e0 lib/kobject_uevent.c:631
 driver_register+0x2d4/0x320 drivers/base/driver.c:257
 virtio_console_init+0x7b/0xe0 drivers/char/virtio_console.c:2200
 do_one_initcall+0x250/0x870 init/main.c:1392
 do_initcall_level+0x10a/0x1a0 init/main.c:1454
 do_initcalls+0x59/0xa0 init/main.c:1470
 kernel_init_freeable+0x29d/0x3e0 init/main.c:1703
 kernel_init+0x1d/0x1d0 init/main.c:1593
page_owner free stack trace missing

Memory state around the buggy address:
 ffff8880264fbc80: 00 00 00 00 00 00 00 06 fc fc fc fc fc fc fc fc
 ffff8880264fbd00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880264fbd80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
                   ^
 ffff8880264fbe00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880264fbe80: 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
----------------
Code disassembly (best guess):
   0:	03 00                	add    (%rax),%eax
   2:	00 41 c7             	add    %al,-0x39(%rcx)
   5:	84 24 e0             	test   %ah,(%rax,%riz,8)
   8:	0d 00 00 00 00       	or     $0x0,%eax
   d:	00 00                	add    %al,(%rax)
   f:	0f 1f 44 00 00       	nopl   0x0(%rax,%rax,1)
  14:	49 83 c4 48          	add    $0x48,%r12
  18:	4c 89 e7             	mov    %r12,%rdi
  1b:	e8 f0 c5 13 0a       	call   0xa13c610
  20:	e8 6b dd 38 00       	call   0x38dd90
  25:	fb                   	sti
  26:	4c 8b 65 c8          	mov    -0x38(%rbp),%r12
* 2a:	49 8d bc 24 c8 16 00 	lea    0x16c8(%r12),%rdi <-- trapping instruction
  31:	00
  32:	48 89 f8             	mov    %rdi,%rax
  35:	48 c1 e8 03          	shr    $0x3,%rax
  39:	42 0f b6 04 30       	movzbl (%rax,%r14,1),%eax
  3e:	84 c0                	test   %al,%al