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BUG: KASAN: use-after-free in __tcp_hdrlen include/linux/tcp.h:31 [inline]
BUG: KASAN: use-after-free in qdisc_pkt_len_segs_init+0x7f7/0xa30 net/core/dev.c:4142
Read of size 2 at addr ffff88815f685a74 by task syz.3.6810/1174

CPU: 1 UID: 0 PID: 1174 Comm: syz.3.6810 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
 __tcp_hdrlen include/linux/tcp.h:31 [inline]
 qdisc_pkt_len_segs_init+0x7f7/0xa30 net/core/dev.c:4142
 sch_handle_ingress net/core/dev.c:4479 [inline]
 __netif_receive_skb_core+0x13aa/0x30b0 net/core/dev.c:6055
 __netif_receive_skb_list_core+0x24d/0x830 net/core/dev.c:6279
 __netif_receive_skb_list net/core/dev.c:6346 [inline]
 netif_receive_skb_list_internal+0x995/0xcf0 net/core/dev.c:6437
 gro_normal_list include/net/gro.h:523 [inline]
 gro_flush_normal include/net/gro.h:531 [inline]
 napi_complete_done+0x299/0x730 net/core/dev.c:6805
 gro_cell_poll+0x5ab/0x5d0 net/core/gro_cells.c:74
 __napi_poll+0xaa/0x330 net/core/dev.c:7727
 napi_poll net/core/dev.c:7790 [inline]
 net_rx_action+0x61d/0xf50 net/core/dev.c:7947
 handle_softirqs+0x225/0x840 kernel/softirq.c:622
 do_softirq+0x76/0xd0 kernel/softirq.c:523
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 tun_rx_batched+0x616/0x790 drivers/net/tun.c:-1
 tun_get_user+0x2b04/0x4350 drivers/net/tun.c:1986
 tun_chr_write_iter+0x113/0x200 drivers/net/tun.c:2032
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x612/0xba0 fs/read_write.c:688
 ksys_write+0x150/0x270 fs/read_write.c:740
 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
RIP: 0033:0x7f450d59ce59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f450e45f028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f450d815fa0 RCX: 00007f450d59ce59
RDX: 000000000000fdef RSI: 0000200000000440 RDI: 0000000000000005
RBP: 00007f450d632d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f450d816038 R14: 00007f450d815fa0 R15: 00007fff632f5a18
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x15f685
flags: 0x57ff00000000000(node=1|zone=2|lastcpupid=0x7ff)
raw: 057ff00000000000 dead000000000100 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x29c2(GFP_NOWAIT|__GFP_HIGHMEM|__GFP_IO|__GFP_FS|__GFP_ZERO), pid 22820, tgid 22816 (syz.4.4132), ts 697501074792, free_ts 697705037727
 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_pages_mpol+0x212/0x380 mm/mempolicy.c:2490
 alloc_frozen_pages_noprof mm/mempolicy.c:2561 [inline]
 alloc_pages_noprof+0xac/0x2a0 mm/mempolicy.c:2581
 vm_area_alloc_pages mm/vmalloc.c:3653 [inline]
 __vmalloc_area_node mm/vmalloc.c:3878 [inline]
 __vmalloc_node_range_noprof+0x795/0x1730 mm/vmalloc.c:4064
 __vmalloc_node_noprof mm/vmalloc.c:4124 [inline]
 vzalloc_noprof+0xb2/0xe0 mm/vmalloc.c:4202
 alloc_one_pg_vec_page net/packet/af_packet.c:4377 [inline]
 alloc_pg_vec net/packet/af_packet.c:4402 [inline]
 packet_set_ring+0x71a/0x2470 net/packet/af_packet.c:4487
 packet_setsockopt+0xd9c/0x1510 net/packet/af_packet.c:3845
 do_sock_setsockopt+0x17c/0x1b0 net/socket.c:2382
 __sys_setsockopt net/socket.c:2407 [inline]
 __do_sys_setsockopt net/socket.c:2413 [inline]
 __se_sys_setsockopt net/socket.c:2410 [inline]
 __x64_sys_setsockopt+0x13d/0x1b0 net/socket.c:2410
 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
page last free pid 22820 tgid 22816 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1397 [inline]
 __free_frozen_pages+0xc0d/0xd20 mm/page_alloc.c:2938
 vfree+0x1fd/0x330 mm/vmalloc.c:3472
 free_pg_vec net/packet/af_packet.c:4356 [inline]
 packet_set_ring+0x197a/0x2470 net/packet/af_packet.c:4577
 packet_release+0x85d/0xd30 net/packet/af_packet.c:3163
 __sock_release net/socket.c:722 [inline]
 sock_close+0xad/0x220 net/socket.c:1515
 __fput+0x418/0xa50 fs/file_table.c:510
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x73a/0x2360 kernel/exit.c:976
 do_group_exit+0x22d/0x2f0 kernel/exit.c:1119
 get_signal+0x121b/0x12c0 kernel/signal.c:3038
 arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop+0xa9/0x6b0 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x353/0x580 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88815f685900: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88815f685980: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88815f685a00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                                             ^
 ffff88815f685a80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88815f685b00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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