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charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 3f0e9c8cefa9 Merge tag 'block-6.19-20251226' of git://git... git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=12f11bb4580000 kernel config: https://syzkaller.appspot.com/x/.config?x=a11e0f726bfb6765 dashboard link: https://syzkaller.appspot.com/bug?extid=3e68572cf2286ce5ebe9 compiler: gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1545c89a580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16e6089a580000 Downloadable assets: disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-3f0e9c8c.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/9dd462c6c761/vmlinux-3f0e9c8c.xz kernel image: https://storage.googleapis.com/syzbot-assets/cb19f02fe3f9/bzImage-3f0e9c8c.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+3e68572cf2286ce5ebe9@syzkaller.appspotmail.com ------------[ cut here ]------------ WARNING: net/core/skbuff.c:7243 at skb_attempt_defer_free+0x641/0x710 net/core/skbuff.c:7243, CPU#3: syz.0.20/6099 Modules linked in: CPU: 3 UID: 0 PID: 6099 Comm: syz.0.20 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 RIP: 0010:skb_attempt_defer_free+0x641/0x710 net/core/skbuff.c:7243 Code: 66 e6 f8 e9 5d ff ff ff e8 fc 8b 7c f8 90 0f 0b 90 e9 f0 fc ff ff e8 ee 8b 7c f8 90 0f 0b 90 e9 74 fc ff ff e8 e0 8b 7c f8 90 <0f> 0b 90 e9 95 fc ff ff e8 d2 8b 7c f8 90 0f 0b 90 48 b8 00 00 00 RSP: 0018:ffffc9000463f5a8 EFLAGS: 00010293 RAX: 0000000000000000 RBX: ffff888053a2d180 RCX: ffffffff894256f5 RDX: ffff88802644a4c0 RSI: ffffffff89425a90 RDI: ffff888053a2d1e0 RBP: 0000000000000000 R08: 0000000000000007 R09: 0000000000000001 R10: 0000000000000000 R11: ffff88802644aff0 R12: 0000000000000000 R13: 1ffff920008c7eb9 R14: 0000000000000000 R15: ffff888053a2d1d8 FS: 00007fad2f19c6c0(0000) GS:ffff8880d6bf5000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fad2f19bf98 CR3: 000000002ccfd000 CR4: 0000000000352ef0 Call Trace: skb_consume_udp+0x19f/0x250 net/ipv4/udp.c:1854 udp_recvmsg+0x6c7/0x1350 net/ipv4/udp.c:2145 sk_udp_recvmsg+0x9b/0x120 net/ipv4/udp_bpf.c:20 udp_bpf_recvmsg net/ipv4/udp_bpf.c:94 [inline] udp_bpf_recvmsg+0x5c0/0xe40 net/ipv4/udp_bpf.c:62 inet_recvmsg+0x625/0x6a0 net/ipv4/af_inet.c:891 sock_recvmsg_nosec net/socket.c:1078 [inline] sock_recvmsg+0x1b2/0x250 net/socket.c:1100 ____sys_recvmsg+0x218/0x6b0 net/socket.c:2812 ___sys_recvmsg+0x114/0x1a0 net/socket.c:2854 do_recvmmsg+0x2fe/0x750 net/socket.c:2949 __sys_recvmmsg net/socket.c:3023 [inline] __do_sys_recvmmsg net/socket.c:3046 [inline] __se_sys_recvmmsg net/socket.c:3039 [inline] __x64_sys_recvmmsg+0x22a/0x280 net/socket.c:3039 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fad2e38f7c9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fad2f19c038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007fad2e5e6090 RCX: 00007fad2e38f7c9 RDX: 0000000000000001 RSI: 00002000000047c0 RDI: 0000000000000003 RBP: 00007fad2e413f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fad2e5e6128 R14: 00007fad2e5e6090 R15: 00007ffd88783058 --- 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 syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing. 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