From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo1-f77.google.com (mail-oo1-f77.google.com [209.85.161.77]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2CAC82571D7 for ; Sun, 7 Jun 2026 06:33:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.77 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780814014; cv=none; b=H84gQoh7rLtJH1DjMW0c/HZioEmXLJBag059oAS75jiwhTuM8UiBTKv+UvnWCE5XGEIhXXOWuCfPWwnYpgQeRwyXERTkNPUlFJ9K+bbE/em2kMrFtirZeTmIO1JaQE6HkzysuQfHKGRBS+VuI5KB9l5ZnHwxiRXUHzxucB+ZU4Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780814014; c=relaxed/simple; bh=UMr5FMnYWkanLZ/Jc8Z9Nz1h8XihtB/2zR4M1WZ8icg=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=EjB6trespKi46z5b21e69XxYI17eou/BBdpLvDE6cOZvnFX877Xd7v28GqraE658f4/VPupUh58+xR/+7MGIBYkKUdjZLBWPb5kyfkOxldQe9ljQslGmtK5fbP5LcqmdIY3icPDJX2122He3iqCGU+ueRg1KP0T801shSjMnU3Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.161.77 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-oo1-f77.google.com with SMTP id 006d021491bc7-69e3464b1afso4703868eaf.0 for ; Sat, 06 Jun 2026 23:33:33 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1780814012; x=1781418812; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=I6fHmm8iEbnH+I5IfhLkxKM674mSo16ZCKnZDZT2OUA=; b=COewtk3+UDDtYYJ1yNFuWJmGe53HZKHDI1MhGEd2cp55GCmjpEOkZp46+0JaL8EQMH H93AvO1rmxeyU7IrQ/LIlrp6fE/iNg7Wrm5u2yuauPTdT/V+OdzbRR+xp9k5OmUPBSsl jZEJ7PGsOjdpIPhK4an7OY1cpM/aXBQ0snu1/uLrSRN7nuNh1qFS9EUhBZ01d21hQD9b 5xlVs4Yu4F2fQcAeBESrA6XsfsbWl184+PCbItRQYivUfeNrc8SaKojRK+sJerCeXKoe tPYgBwSLAWRCLq4dkZu7hQfh4cTmXk3Ih7iQcWRUXMy1zX8qBuchV7NOMQtn0+IzoXa2 Rpaw== X-Forwarded-Encrypted: i=1; AFNElJ8o1bEKEXtcQxC28H0w+MyCh9Kv9s/vX9B/svBjDFpnoMMZWbRdronZNA8ZJ8m1DgNF7E4lnjQ=@vger.kernel.org X-Gm-Message-State: AOJu0Yx9tVcYned2IOIbd6uOOQZU43rWE/jydxIhBvABhjncohphyK/1 nSkIzcC4iCfD/DH1L6OizUte+fguvnUla6zxqsGhpJXNX2ezWZKHb1Y+J+K8roqzBYiZ0hibKKE U5pJT8s/KTK37Y5lDU1iGQ9EIDWgWdQQhGbeLNRCo1FdUAk2v1QH+z7Ixtss= Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:1609:b0:69e:8976:77d9 with SMTP id 006d021491bc7-69e897678c5mr1012559eaf.40.1780814012129; Sat, 06 Jun 2026 23:33:32 -0700 (PDT) Date: Sat, 06 Jun 2026 23:33:32 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a2510bc.39669fcc.33b062.000c.GAE@google.com> Subject: [syzbot] [net?] KASAN: slab-use-after-free Read in sit_tunnel_xmit From: syzbot To: davem@davemloft.net, edumazet@google.com, horms@kernel.org, kuba@kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, pabeni@redhat.com, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: c93952cc0034 Merge branch 'intel-wired-lan-driver-updates-.. git tree: net console output: https://syzkaller.appspot.com/x/log.txt?x=16b1eb7e580000 kernel config: https://syzkaller.appspot.com/x/.config?x=65472e27d1590a04 dashboard link: https://syzkaller.appspot.com/bug?extid=6eb9ca986d80f6f88cf9 compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/ae72ddffba02/disk-c93952cc.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/a9090edc4303/vmlinux-c93952cc.xz kernel image: https://storage.googleapis.com/syzbot-assets/403385dab708/bzImage-c93952cc.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+6eb9ca986d80f6f88cf9@syzkaller.appspotmail.com ================================================================== BUG: KASAN: slab-use-after-free in ipv6_get_dsfield include/net/dsfield.h:24 [inline] BUG: KASAN: slab-use-after-free in ipip6_tunnel_xmit net/ipv6/sit.c:1021 [inline] BUG: KASAN: slab-use-after-free in sit_tunnel_xmit+0x19b5/0x1b80 net/ipv6/sit.c:1072 Read of size 2 at addr ffff88801bba9760 by task syz.0.1430/10890 CPU: 0 UID: 0 PID: 10890 Comm: syz.0.1430 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Call Trace: 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 ipv6_get_dsfield include/net/dsfield.h:24 [inline] ipip6_tunnel_xmit net/ipv6/sit.c:1021 [inline] sit_tunnel_xmit+0x19b5/0x1b80 net/ipv6/sit.c:1072 __netdev_start_xmit include/linux/netdevice.h:5368 [inline] netdev_start_xmit include/linux/netdevice.h:5377 [inline] xmit_one net/core/dev.c:3888 [inline] dev_hard_start_xmit+0x2cd/0x830 net/core/dev.c:3904 __dev_queue_xmit+0x14d9/0x3950 net/core/dev.c:4870 packet_snd net/packet/af_packet.c:3082 [inline] packet_sendmsg+0x3c81/0x4fb0 net/packet/af_packet.c:3114 sock_sendmsg_nosec net/socket.c:787 [inline] __sock_sendmsg net/socket.c:802 [inline] __sys_sendto+0x672/0x710 net/socket.c:2265 __do_sys_sendto net/socket.c:2272 [inline] __se_sys_sendto net/socket.c:2268 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2268 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: 0033:0x7ff06c39ce59 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:00007ff06d1e8028 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007ff06c615fa0 RCX: 00007ff06c39ce59 RDX: 000000000000fc13 RSI: 0000200000000280 RDI: 0000000000000005 RBP: 00007ff06c432d6f R08: 0000000000000000 R09: 000000000000002f R10: 0000000000000800 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ff06c616038 R14: 00007ff06c615fa0 R15: 00007ffe13a440e8 Allocated by task 10890: 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:4570 [inline] slab_alloc_node mm/slub.c:4899 [inline] kmem_cache_alloc_node_noprof+0x384/0x690 mm/slub.c:4951 kmalloc_reserve net/core/skbuff.c:613 [inline] __alloc_skb+0x27d/0x7d0 net/core/skbuff.c:713 alloc_skb include/linux/skbuff.h:1385 [inline] alloc_skb_with_frags+0xc8/0x760 net/core/skbuff.c:6766 sock_alloc_send_pskb+0x878/0x990 net/core/sock.c:3002 packet_alloc_skb net/packet/af_packet.c:2932 [inline] packet_snd net/packet/af_packet.c:3025 [inline] packet_sendmsg+0x315a/0x4fb0 net/packet/af_packet.c:3114 sock_sendmsg_nosec net/socket.c:787 [inline] __sock_sendmsg net/socket.c:802 [inline] __sys_sendto+0x672/0x710 net/socket.c:2265 __do_sys_sendto net/socket.c:2272 [inline] __se_sys_sendto net/socket.c:2268 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2268 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 10890: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x46/0x50 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] slab_free mm/slub.c:6251 [inline] kfree+0x1c5/0x640 mm/slub.c:6566 skb_kfree_head net/core/skbuff.c:1075 [inline] skb_free_head net/core/skbuff.c:1087 [inline] pskb_expand_head+0x458/0x1390 net/core/skbuff.c:2335 skb_header_unclone include/linux/skbuff.h:2087 [inline] iptunnel_handle_offloads+0x362/0x630 net/ipv4/ip_tunnel_core.c:185 ipip6_tunnel_xmit net/ipv6/sit.c:960 [inline] sit_tunnel_xmit+0x92a/0x1b80 net/ipv6/sit.c:1072 __netdev_start_xmit include/linux/netdevice.h:5368 [inline] netdev_start_xmit include/linux/netdevice.h:5377 [inline] xmit_one net/core/dev.c:3888 [inline] dev_hard_start_xmit+0x2cd/0x830 net/core/dev.c:3904 __dev_queue_xmit+0x14d9/0x3950 net/core/dev.c:4870 packet_snd net/packet/af_packet.c:3082 [inline] packet_sendmsg+0x3c81/0x4fb0 net/packet/af_packet.c:3114 sock_sendmsg_nosec net/socket.c:787 [inline] __sock_sendmsg net/socket.c:802 [inline] __sys_sendto+0x672/0x710 net/socket.c:2265 __do_sys_sendto net/socket.c:2272 [inline] __se_sys_sendto net/socket.c:2268 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2268 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 The buggy address belongs to the object at ffff88801bba96c0 which belongs to the cache skbuff_small_head of size 704 The buggy address is located 160 bytes inside of freed 704-byte region [ffff88801bba96c0, ffff88801bba9980) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1bba8 head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff88801f2ad8c0 dead000000000100 dead000000000122 raw: 0000000000000000 0000000800130013 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801f2ad8c0 dead000000000100 dead000000000122 head: 0000000000000000 0000000800130013 00000000f5000000 0000000000000000 head: 00fff00000000002 ffffffffffffff01 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000004 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5003, tgid 5003 (udevd), ts 31613474311, free_ts 31513004909 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+0x2593/0x2610 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+0x339/0x3d0 mm/slub.c:7272 refill_sheaf mm/slub.c:2816 [inline] __pcs_replace_empty_main+0x321/0x720 mm/slub.c:4652 alloc_from_pcs mm/slub.c:4750 [inline] slab_alloc_node mm/slub.c:4884 [inline] kmem_cache_alloc_node_noprof+0x441/0x690 mm/slub.c:4951 kmalloc_reserve net/core/skbuff.c:613 [inline] __alloc_skb+0x27d/0x7d0 net/core/skbuff.c:713 netlink_sendmsg+0x5d4/0xb40 net/netlink/af_netlink.c:1874 sock_sendmsg_nosec net/socket.c:787 [inline] __sock_sendmsg net/socket.c:802 [inline] ____sys_sendmsg+0x972/0x9f0 net/socket.c:2698 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2752 __sys_sendmsg net/socket.c:2784 [inline] __do_sys_sendmsg net/socket.c:2789 [inline] __se_sys_sendmsg net/socket.c:2787 [inline] __x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2787 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 5001 tgid 5001 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1397 [inline] __free_frozen_pages+0xc1c/0xd30 mm/page_alloc.c:2938 __slab_free+0x274/0x2c0 mm/slub.c:5613 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4570 [inline] slab_alloc_node mm/slub.c:4899 [inline] kmem_cache_alloc_noprof+0x2bc/0x650 mm/slub.c:4906 lsm_file_alloc security/security.c:171 [inline] security_file_alloc+0x34/0x310 security/security.c:2406 init_file+0x90/0x2b0 fs/file_table.c:184 alloc_empty_file+0x74/0x1d0 fs/file_table.c:266 path_openat+0x10f/0x3860 fs/namei.c:4844 do_file_open+0x23e/0x4a0 fs/namei.c:4887 do_sys_openat2+0x113/0x200 fs/open.c:1364 do_sys_open fs/open.c:1370 [inline] __do_sys_openat fs/open.c:1386 [inline] __se_sys_openat fs/open.c:1381 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1381 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: ffff88801bba9600: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff88801bba9680: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb >ffff88801bba9700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88801bba9780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88801bba9800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup