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BUG: KCSAN: data-race in do_tcp_setsockopt.isra.0 / tcp_stream_memory_free

write to 0xffff88809de7dab8 of 4 bytes by task 10278 on cpu 0:
 do_tcp_setsockopt.isra.0+0x70b/0x16e0 net/ipv4/tcp.c:3138
 tcp_setsockopt+0x9d/0xb0 net/ipv4/tcp.c:3169
 sock_common_setsockopt+0x5d/0x80 net/core/sock.c:3172
 __sys_setsockopt+0x1d6/0x380 net/socket.c:2132
 __do_sys_setsockopt net/socket.c:2148 [inline]
 __se_sys_setsockopt net/socket.c:2145 [inline]
 __x64_sys_setsockopt+0x6b/0x80 net/socket.c:2145
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88809de7dab8 of 4 bytes by task 10281 on cpu 1:
 tcp_notsent_lowat include/net/tcp.h:1950 [inline]
 tcp_stream_memory_free+0x86/0x100 include/net/tcp.h:1963
 __sk_stream_memory_free include/net/sock.h:1265 [inline]
 __sk_stream_memory_free include/net/sock.h:1259 [inline]
 sk_stream_memory_free include/net/sock.h:1270 [inline]
 sk_stream_wait_memory+0x6a8/0x850 net/core/stream.c:145
 tcp_sendmsg_locked+0x98c/0x20f0 net/ipv4/tcp.c:1393
 tcp_sendmsg+0x35/0x50 net/ipv4/tcp.c:1433
 inet_sendmsg+0x69/0x90 net/ipv4/af_inet.c:807
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0x98/0xc0 net/socket.c:672
 __sys_sendto+0x1e2/0x2c0 net/socket.c:2000
 __do_sys_sendto net/socket.c:2012 [inline]
 __se_sys_sendto net/socket.c:2008 [inline]
 __x64_sys_sendto+0x7e/0xa0 net/socket.c:2008
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 10281 Comm: syz-executor.5 Not tainted 5.7.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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