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TCP recvmsg seq # bug 2: copied AC35EBA9, seq AC35EB71, rcvnxt AC35EB72, fl 40
WARNING: CPU: 0 PID: 6639 at net/ipv4/tcp.c:2706 tcp_recvmsg_locked+0x80e/0x3660 net/ipv4/tcp.c:2704
Modules linked in:
CPU: 0 UID: 0 PID: 6639 Comm: syz.0.65 Not tainted 6.15.0-syzkaller-07774-g90b83efa6701 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:tcp_recvmsg_locked+0x80e/0x3660 net/ipv4/tcp.c:2704
Code: 48 c1 e8 03 42 0f b6 04 28 84 c0 4c 8b 74 24 18 0f 85 35 01 00 00 8b 0f 48 c7 c7 20 17 9a 8c 44 8b 44 24 3c e8 83 53 b1 f7 90 <0f> 0b 90 90 e9 40 ff ff ff 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c 10
RSP: 0018:ffffc90003f0f240 EFLAGS: 00010246
RAX: 60cf62a03c71f200 RBX: 0000000000000000 RCX: ffff8880277c3c00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000002
RBP: ffffc90003f0f610 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff1bfa66c R12: ffff8880324300f0
R13: dffffc0000000000 R14: ffff888075db33e8 R15: ffff888032430118
FS:  00007fa8a2d7f6c0(0000) GS:ffff888125c98000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c002806000 CR3: 000000007685e000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 receive_fallback_to_copy net/ipv4/tcp.c:1948 [inline]
 tcp_zerocopy_receive+0x800/0x21d0 net/ipv4/tcp.c:2180
 do_tcp_getsockopt+0x1dd2/0x2610 net/ipv4/tcp.c:4663
 tcp_getsockopt+0x89/0x130 net/ipv4/tcp.c:4762
 do_sock_getsockopt+0x35d/0x650 net/socket.c:2357
 __sys_getsockopt net/socket.c:2386 [inline]
 __do_sys_getsockopt net/socket.c:2393 [inline]
 __se_sys_getsockopt net/socket.c:2390 [inline]
 __x64_sys_getsockopt+0x1a5/0x250 net/socket.c:2390
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa8a1f7e819
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:00007fa8a2d7f038 EFLAGS: 00000246 ORIG_RAX: 0000000000000037
RAX: ffffffffffffffda RBX: 00007fa8a2135fa0 RCX: 00007fa8a1f7e819
RDX: 0000000000000023 RSI: 0000000000000006 RDI: 0000000000000003
RBP: 00007fa8a1ff175e R08: 00000000200004c0 R09: 0000000000000000
R10: 0000000020000380 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fa8a2135fa0 R15: 00007fff4163b378
 </TASK>