==================================================================
BUG: KASAN: slab-use-after-free in fib_rules_lookup+0x15e/0xeb0 net/core/fib_rules.c:321
Read of size 8 at addr ffff8880299f1780 by task ktimers/0/16

CPU: 0 UID: 0 PID: 16 Comm: ktimers/0 Tainted: G             L      syzkaller #0 PREEMPT_{RT,(full)} 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
 <TASK>
 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
 __ip_route_output_key include/net/route.h:169 [inline]
 ip_route_output_flow+0x2a/0x150 net/ipv4/route.c:2929
 ip_route_output_key include/net/route.h:179 [inline]
 ip_tunnel_xmit+0x6ce/0x2040 net/ipv4/ip_tunnel.c:782
 __gre_xmit net/ipv4/ip_gre.c:491 [inline]
 ipgre_xmit+0x90a/0xcd0 net/ipv4/ip_gre.c:695
 __netdev_start_xmit include/linux/netdevice.h:5406 [inline]
 netdev_start_xmit include/linux/netdevice.h:5415 [inline]
 xmit_one net/core/dev.c:3890 [inline]
 dev_hard_start_xmit+0x2df/0x870 net/core/dev.c:3906
 __dev_queue_xmit+0x1549/0x3890 net/core/dev.c:4873
 neigh_output include/net/neighbour.h:560 [inline]
 ip_finish_output2+0xc98/0x1100 net/ipv4/ip_output.c:236
 iptunnel_xmit+0x61b/0xd70 net/ipv4/ip_tunnel_core.c:97
 udp_tunnel_xmit_skb+0x27f/0x3c0 net/ipv4/udp_tunnel_core.c:187
 tipc_udp_xmit+0x80c/0xb30 net/tipc/udp_media.c:197
 tipc_bearer_xmit_skb+0x2b3/0x400 net/tipc/bearer.c:576
 tipc_disc_timeout+0x642/0x790 net/tipc/discover.c:338
 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+0x67b/0x9b0 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+0x1d9/0x6c0 kernel/softirq.c:626
 __do_softirq kernel/softirq.c:660 [inline]
 run_ktimerd+0x69/0x100 kernel/softirq.c:1155
 smpboot_thread_fn+0x57c/0xa80 kernel/smpboot.c:160
 kthread+0x388/0x470 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 17835:
 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:5360 [inline]
 __kmalloc_node_track_caller_noprof+0x57f/0x7c0 mm/slub.c:5495
 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:3267
 __do_sys_unshare kernel/fork.c:3341 [inline]
 __se_sys_unshare kernel/fork.c:3339 [inline]
 __x64_sys_unshare+0x38/0x50 kernel/fork.c:3339
 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 1174:
 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:2703 [inline]
 slab_free_freelist_hook mm/slub.c:2732 [inline]
 slab_free_bulk mm/slub.c:6437 [inline]
 kmem_cache_free_bulk+0x309/0x1260 mm/slub.c:7174
 kfree_bulk include/linux/slab.h:891 [inline]
 kvfree_rcu_bulk+0xc6/0x190 mm/slab_common.c:1502
 kfree_rcu_work+0xe8/0x160 mm/slab_common.c:1580
 process_one_work+0x93a/0x12b0 kernel/workqueue.c:3326
 process_scheduled_works kernel/workqueue.c:3409 [inline]
 worker_thread+0xb05/0x10d0 kernel/workqueue.c:3490
 kthread+0x388/0x470 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

Last potentially related work creation:
 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57
 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556
 kvfree_call_rcu+0x90/0x3c0 mm/slab_common.c:1970
 ops_exit_rtnl_list net/core/net_namespace.c:181 [inline]
 ops_undo_list+0x319/0x8d0 net/core/net_namespace.c:248
 cleanup_net+0x575/0x810 net/core/net_namespace.c:702
 process_one_work+0x93a/0x12b0 kernel/workqueue.c:3326
 process_scheduled_works kernel/workqueue.c:3409 [inline]
 worker_thread+0xb05/0x10d0 kernel/workqueue.c:3490
 kthread+0x388/0x470 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 ffff8880299f1700
 which belongs to the cache kmalloc-192 of size 192
The buggy address is located 128 bytes inside of
 freed 192-byte region [ffff8880299f1700, ffff8880299f17c0)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff8880299f1500 pfn:0x299f1
flags: 0x80000000000200(workingset|node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000200 ffff88813fe1f3c0 ffffea0000f13bd0 ffffea0001072850
raw: ffff8880299f1500 0000000800100005 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 5603, tgid 5603 (syz-executor), ts 89124543304, free_ts 89097287664
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1859
 prep_new_page mm/page_alloc.c:1867 [inline]
 get_page_from_freelist+0x2639/0x26b0 mm/page_alloc.c:3946
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5304
 alloc_slab_page mm/slub.c:3292 [inline]
 allocate_slab+0x79/0x5e0 mm/slub.c:3406
 new_slab mm/slub.c:3452 [inline]
 refill_objects+0x2d8/0x350 mm/slub.c:7336
 refill_sheaf mm/slub.c:2830 [inline]
 __pcs_replace_empty_main+0x330/0x690 mm/slub.c:4701
 alloc_from_pcs mm/slub.c:4799 [inline]
 slab_alloc_node mm/slub.c:4931 [inline]
 __do_kmalloc_node mm/slub.c:5359 [inline]
 __kmalloc_flags_noprof+0x653/0x830 mm/slub.c:5552
 _kmalloc_flags_noprof mm/slab.h:38 [inline]
 alloc_slab_obj_exts+0xb7/0x230 mm/slub.c:2179
 __memcg_slab_post_alloc_hook+0x602/0xf60 mm/memcontrol.c:3587
 memcg_slab_post_alloc_hook mm/slub.c:2473 [inline]
 slab_post_alloc_hook mm/slub.c:4629 [inline]
 slab_alloc_node mm/slub.c:4943 [inline]
 kmem_cache_alloc_lru_noprof+0x410/0x650 mm/slub.c:4976
 __d_alloc+0x37/0x6f0 fs/dcache.c:1902
 d_alloc_pseudo+0x21/0xc0 fs/dcache.c:2033
 alloc_path_pseudo+0x107/0x220 fs/file_table.c:407
 alloc_file_pseudo+0xa8/0x1e0 fs/file_table.c:423
 sock_alloc_file net/socket.c:532 [inline]
 sock_map_fd net/socket.c:562 [inline]
 __sys_socket+0x1c1/0x320 net/socket.c:1817
 __do_sys_socket net/socket.c:1822 [inline]
 __se_sys_socket net/socket.c:1820 [inline]
 __x64_sys_socket+0x7a/0x90 net/socket.c:1820
page last free pid 5948 tgid 5948 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1406 [inline]
 __free_frozen_pages+0x10de/0x11c0 mm/page_alloc.c:2950
 tlb_batch_list_free mm/mmu_gather.c:161 [inline]
 tlb_finish_mmu+0x13e/0x220 mm/mmu_gather.c:552
 exit_mmap+0x4b2/0x9f0 mm/mmap.c:1313
 __mmput+0xcb/0x3e0 kernel/fork.c:1182
 exit_mm+0x186/0x240 kernel/exit.c:610
 do_exit+0x6cd/0x2360 kernel/exit.c:992
 do_group_exit+0x22d/0x2f0 kernel/exit.c:1147
 __do_sys_exit_group kernel/exit.c:1158 [inline]
 __se_sys_exit_group kernel/exit.c:1156 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1156
 x64_sys_call+0x221a/0x2240 arch/x86/include/generated/asm/syscalls_64.h:232
 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

Memory state around the buggy address:
 ffff8880299f1680: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff8880299f1700: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880299f1780: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
                   ^
 ffff8880299f1800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880299f1880: 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================