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TCP recvmsg seq # bug 2: copied CD63F270, seq CD63F238, rcvnxt CD63F239, fl 40
WARNING: CPU: 2 PID: 6495 at net/ipv4/tcp.c:2704 tcp_recvmsg_locked+0xb5c/0x2880 net/ipv4/tcp.c:2704
Modules linked in:
CPU: 2 UID: 0 PID: 6495 Comm: syz.0.26 Not tainted 6.15.0-syzkaller-g90b83efa6701 #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:tcp_recvmsg_locked+0xb5c/0x2880 net/ipv4/tcp.c:2704
Code: 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 15 1b 00 00 48 8b 04 24 44 8b 44 24 30 89 da 48 c7 c7 80 23 ce 8c 8b 30 e8 d5 68 93 f7 90 <0f> 0b 90 90 e9 ac f9 ff ff e8 c6 39 d4 f7 49 8d 5c 24 60 be 08 00
RSP: 0018:ffffc90003827498 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 00000000cd63f238 RCX: ffffffff817aa908
RDX: ffff8880248f8000 RSI: ffffffff817aa915 RDI: 0000000000000001
RBP: ffff88802b1ae424 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: ffff88802b1ae418
R13: ffff88802b1ae3f0 R14: 0000000000000001 R15: dffffc0000000000
FS:  00007f127ae956c0(0000) GS:ffff8880d6b74000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000002000cf3d CR3: 000000004ed22000 CR4: 0000000000352ef0
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+0x12db/0x20f0 net/ipv4/tcp.c:2180
 do_tcp_getsockopt+0x10f5/0x26c0 net/ipv4/tcp.c:4663
 tcp_getsockopt+0xdf/0x100 net/ipv4/tcp.c:4762
 do_sock_getsockopt+0x3fc/0x800 net/socket.c:2357
 __sys_getsockopt+0x12f/0x260 net/socket.c:2386
 __do_sys_getsockopt net/socket.c:2393 [inline]
 __se_sys_getsockopt net/socket.c:2390 [inline]
 __x64_sys_getsockopt+0xbd/0x160 net/socket.c:2390
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f127a17dff9
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:00007f127ae95038 EFLAGS: 00000246 ORIG_RAX: 0000000000000037
RAX: ffffffffffffffda RBX: 00007f127a335f80 RCX: 00007f127a17dff9
RDX: 0000000000000023 RSI: 0000000000000006 RDI: 0000000000000003
RBP: 00007f127a1f0296 R08: 00000000200004c0 R09: 0000000000000000
R10: 0000000020000380 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f127a335f80 R15: 00007ffc6df60728
 </TASK>