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TCP recvmsg seq # bug 2: copied 78E97D5, seq 78E979D, rcvnxt 78E979E, fl 40
WARNING: CPU: 1 PID: 6958 at net/ipv4/tcp.c:2726 tcp_recvmsg_locked+0x82c/0x35c0 net/ipv4/tcp.c:2724
Modules linked in:
CPU: 1 UID: 0 PID: 6958 Comm: syz.0.128 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:tcp_recvmsg_locked+0x82c/0x35c0 net/ipv4/tcp.c:2724
Code: 17 4c 89 c0 48 c1 e8 03 42 0f b6 04 20 84 c0 0f 85 3a 01 00 00 41 8b 08 48 c7 c7 c0 53 e7 8b 44 8b 44 24 3c e8 15 12 4e f8 90 <0f> 0b 90 90 e9 3c ff ff ff 89 f9 80 e1 07 80 c1 03 38 c1 0f 8c f9
RSP: 0018:ffffc900040df1e0 EFLAGS: 00010246
RAX: 0ca3a30b5d32a600 RBX: 0000000000000000 RCX: ffff88802ee3da00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900040df5d0 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed101712487b R12: dffffc0000000000
R13: ffff888056188128 R14: 1ffff11006a62513 R15: dffffc0000000000
FS:  00007facb41e66c0(0000) GS:ffff888126ef9000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020003ff6 CR3: 00000000291f6000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 receive_fallback_to_copy net/ipv4/tcp.c:1968 [inline]
 tcp_zerocopy_receive+0x800/0x21d0 net/ipv4/tcp.c:2200
 do_tcp_getsockopt+0x1dd0/0x2680 net/ipv4/tcp.c:4713
 tcp_getsockopt+0x83/0x130 net/ipv4/tcp.c:4812
 do_sock_getsockopt+0x372/0x450 net/socket.c:2421
 __sys_getsockopt net/socket.c:2450 [inline]
 __do_sys_getsockopt net/socket.c:2457 [inline]
 __se_sys_getsockopt net/socket.c:2454 [inline]
 __x64_sys_getsockopt+0x1ab/0x250 net/socket.c:2454
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7facb4f6e819
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:00007facb41e6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000037
RAX: ffffffffffffffda RBX: 00007facb5125fa0 RCX: 00007facb4f6e819
RDX: 0000000000000023 RSI: 0000000000000006 RDI: 0000000000000003
RBP: 00007facb4fe175e R08: 00000000200004c0 R09: 0000000000000000
R10: 0000000020000380 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007facb5125fa0 R15: 00007ffe12224628
 </TASK>