==================================================================
BUG: KASAN: slab-use-after-free in skb_network_header include/linux/skbuff.h:2952 [inline]
BUG: KASAN: slab-use-after-free in ipv6_hdr include/linux/ipv6.h:101 [inline]
BUG: KASAN: slab-use-after-free in nf_nat_ipv6_in+0x141/0x2c0 net/netfilter/nf_nat_proto.c:949
Read of size 8 at addr ffff888030f27710 by task syz.1.2728/18394

CPU: 0 PID: 18394 Comm: syz.1.2728 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/06/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:364 [inline]
 print_report+0xa8/0x210 mm/kasan/report.c:468
 kasan_report+0x117/0x150 mm/kasan/report.c:581
 skb_network_header include/linux/skbuff.h:2952 [inline]
 ipv6_hdr include/linux/ipv6.h:101 [inline]
 nf_nat_ipv6_in+0x141/0x2c0 net/netfilter/nf_nat_proto.c:949
 nf_hook_entry_hookfn include/linux/netfilter.h:156 [inline]
 nf_hook_slow+0xb9/0x210 net/netfilter/core.c:626
 nf_hook include/linux/netfilter.h:271 [inline]
 NF_HOOK include/linux/netfilter.h:314 [inline]
 br_nf_pre_routing_ipv6+0x55b/0x6a0 net/bridge/br_netfilter_ipv6.c:184
 nf_hook_entry_hookfn include/linux/netfilter.h:156 [inline]
 nf_hook_bridge_pre net/bridge/br_input.c:277 [inline]
 br_handle_frame+0x12fa/0x15b0 net/bridge/br_input.c:433
 __netif_receive_skb_core+0xf94/0x3ac0 net/core/dev.c:5604
 __netif_receive_skb_one_core net/core/dev.c:5708 [inline]
 __netif_receive_skb+0x74/0x290 net/core/dev.c:5824
 netif_receive_skb_internal net/core/dev.c:5910 [inline]
 netif_receive_skb+0x1bc/0x720 net/core/dev.c:5969
 tun_rx_batched+0x1df/0x790 drivers/net/tun.c:1561
 tun_get_user+0x286c/0x3d30 drivers/net/tun.c:2020
 tun_chr_write_iter+0x119/0x200 drivers/net/tun.c:2066
 call_write_iter include/linux/fs.h:2019 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x474/0x9a0 fs/read_write.c:584
 ksys_write+0x151/0x260 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f75fe569d0e
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007f75ff39bfb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f75ff39c6c0 RCX: 00007f75fe569d0e
RDX: 000000000000008e RSI: 00002000000004c0 RDI: 00000000000000c8
RBP: 00007f75fe63804e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f75fe826308 R14: 00007f75fe826270 R15: 00007ffda7711ea8
 </TASK>

Allocated by task 18394:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:53
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:188 [inline]
 slab_post_alloc_hook+0x6a/0x4d0 mm/slab.h:770
 slab_alloc_node mm/slub.c:3518 [inline]
 slab_alloc mm/slub.c:3526 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3533 [inline]
 kmem_cache_alloc+0x17e/0x2d0 mm/slub.c:3542
 __build_skb net/core/skbuff.c:451 [inline]
 build_skb+0x29/0x250 net/core/skbuff.c:466
 __tun_build_skb+0x36/0x320 drivers/net/tun.c:1616
 tun_build_skb drivers/net/tun.c:1707 [inline]
 tun_get_user+0x1cb8/0x3d30 drivers/net/tun.c:1831
 tun_chr_write_iter+0x119/0x200 drivers/net/tun.c:2066
 call_write_iter include/linux/fs.h:2019 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x474/0x9a0 fs/read_write.c:584
 ksys_write+0x151/0x260 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Freed by task 18394:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:53
 kasan_save_free_info+0x28/0x40 mm/kasan/generic.c:522
 ____kasan_slab_free+0x126/0x1f0 mm/kasan/common.c:237
 kasan_slab_free include/linux/kasan.h:164 [inline]
 slab_free_hook mm/slub.c:1833 [inline]
 slab_free_freelist_hook+0x154/0x240 mm/slub.c:1859
 slab_free mm/slub.c:3853 [inline]
 kmem_cache_free+0xf8/0x290 mm/slub.c:3875
 NF_DROP_REASON include/linux/netfilter.h:30 [inline]
 nft_do_chain+0x14d9/0x16d0 net/netfilter/nf_tables_core.c:-1
 nft_nat_do_chain+0x29b/0x380 net/netfilter/nft_chain_nat.c:32
 nf_nat_inet_fn+0x5dd/0xb20 net/netfilter/nf_nat_core.c:958
 nf_nat_ipv6_fn+0x227/0x2e0 net/netfilter/nf_nat_proto.c:937
 nf_nat_ipv6_in+0xf1/0x2c0 net/netfilter/nf_nat_proto.c:947
 nf_hook_entry_hookfn include/linux/netfilter.h:156 [inline]
 nf_hook_slow+0xb9/0x210 net/netfilter/core.c:626
 nf_hook include/linux/netfilter.h:271 [inline]
 NF_HOOK include/linux/netfilter.h:314 [inline]
 br_nf_pre_routing_ipv6+0x55b/0x6a0 net/bridge/br_netfilter_ipv6.c:184
 nf_hook_entry_hookfn include/linux/netfilter.h:156 [inline]
 nf_hook_bridge_pre net/bridge/br_input.c:277 [inline]
 br_handle_frame+0x12fa/0x15b0 net/bridge/br_input.c:433
 __netif_receive_skb_core+0xf94/0x3ac0 net/core/dev.c:5604
 __netif_receive_skb_one_core net/core/dev.c:5708 [inline]
 __netif_receive_skb+0x74/0x290 net/core/dev.c:5824
 netif_receive_skb_internal net/core/dev.c:5910 [inline]
 netif_receive_skb+0x1bc/0x720 net/core/dev.c:5969
 tun_rx_batched+0x1df/0x790 drivers/net/tun.c:1561
 tun_get_user+0x286c/0x3d30 drivers/net/tun.c:2020
 tun_chr_write_iter+0x119/0x200 drivers/net/tun.c:2066
 call_write_iter include/linux/fs.h:2019 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x474/0x9a0 fs/read_write.c:584
 ksys_write+0x151/0x260 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

The buggy address belongs to the object at ffff888030f27640
 which belongs to the cache skbuff_head_cache of size 240
The buggy address is located 208 bytes inside of
 freed 240-byte region [ffff888030f27640, ffff888030f27730)

The buggy address belongs to the physical page:
page:ffffea0000c3c9c0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x30f27
memcg:ffff888075d78401
flags: 0xfff00000000800(slab|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000800 ffff888141e5b000 dead000000000100 dead000000000122
raw: 0000000000000000 00000000800c000c 00000001ffffffff ffff888075d78401
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x112820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_HARDWALL), pid 2944, tgid 2944 (kworker/u4:8), ts 382708034036, free_ts 374772520641
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x1c1/0x200 mm/page_alloc.c:1582
 prep_new_page mm/page_alloc.c:1589 [inline]
 get_page_from_freelist+0x2181/0x22a0 mm/page_alloc.c:3221
 __alloc_pages+0x1f0/0x460 mm/page_alloc.c:4501
 alloc_slab_page+0x5d/0x180 mm/slub.c:1903
 allocate_slab mm/slub.c:2050 [inline]
 new_slab+0x87/0x2d0 mm/slub.c:2103
 ___slab_alloc+0xc5c/0x12f0 mm/slub.c:3275
 __slab_alloc mm/slub.c:3361 [inline]
 __slab_alloc_node mm/slub.c:3414 [inline]
 slab_alloc_node mm/slub.c:3508 [inline]
 slab_alloc mm/slub.c:3526 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3533 [inline]
 kmem_cache_alloc+0x109/0x2d0 mm/slub.c:3542
 skb_clone+0x1eb/0x370 net/core/skbuff.c:1915
 batadv_iv_ogm_send_to_if net/batman-adv/bat_iv_ogm.c:390 [inline]
 batadv_iv_ogm_emit net/batman-adv/bat_iv_ogm.c:423 [inline]
 batadv_iv_send_outstanding_bat_ogm_packet+0x5e4/0x800 net/batman-adv/bat_iv_ogm.c:1792
 process_one_work kernel/workqueue.c:2657 [inline]
 process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2734
 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2815
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1182 [inline]
 free_unref_page_prepare+0x7d7/0x8f0 mm/page_alloc.c:2366
 free_unref_page_list+0xbe/0x860 mm/page_alloc.c:2505
 release_pages+0x208a/0x2300 mm/swap.c:1022
 __folio_batch_release+0x71/0xe0 mm/swap.c:1042
 folio_batch_release include/linux/pagevec.h:83 [inline]
 truncate_inode_pages_range+0x381/0xea0 mm/truncate.c:396
 kill_bdev block/bdev.c:76 [inline]
 blkdev_flush_mapping+0x132/0x290 block/bdev.c:645
 blkdev_put_whole block/bdev.c:676 [inline]
 blkdev_put+0x49a/0x7a0 block/bdev.c:954
 blkdev_release+0x84/0x90 block/fops.c:604
 __fput+0x221/0x940 fs/file_table.c:418
 task_work_run+0x1d4/0x260 kernel/task_work.c:245
 get_signal+0x11da/0x1390 kernel/signal.c:2703
 arch_do_signal_or_restart+0xc2/0x7b0 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:213
 __syscall_exit_to_user_mode_work kernel/entry/common.c:294 [inline]
 syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:305
 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:82

Memory state around the buggy address:
 ffff888030f27600: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
 ffff888030f27680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888030f27700: fb fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc
                         ^
 ffff888030f27780: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888030f27800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc
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