Hi Eric,
Makes sense, thanks for taking the time to look at our report.
Best,
Gabe
On Fri, Aug 19, 2022 at 5:24 PM Eric Dumazet <edumazet@xxxxxxxxxx> wrote:
>
> On Fri, Aug 19, 2022 at 8:40 AM Abhishek Shah
> <abhishek.shah@xxxxxxxxxxxx> wrote:
> >
> > Hi all,
> >
>
> Not sure why you included so many people in this report ?
>
> You have not exactly said what could be the issue (other than the raw
> kcsan report)
>
> > We found a race involving the tcp_md5sig_pool_populated variable. Upon further investigation, we think that __tcp_alloc_md5sig_pool can be run multiple times before tcp_md5sig_pool_populated is set to true here. However, we are not sure. Please let us know what you think.
>
> I think this is a false positive, because the data race is properly handled
> with the help of tcp_md5sig_mutex.
>
> We might silence it, of course, like many other existing data races.
>
>
>
> >
> > Thanks!
> >
> >
> > --------------------Report--------------
> >
> > write to 0xffffffff883a2438 of 1 bytes by task 6542 on cpu 0:
> > __tcp_alloc_md5sig_pool+0x239/0x260 net/ipv4/tcp.c:4343
> > tcp_alloc_md5sig_pool+0x58/0xb0 net/ipv4/tcp.c:4352
> > tcp_md5_do_add+0x2c4/0x470 net/ipv4/tcp_ipv4.c:1199
> > tcp_v6_parse_md5_keys+0x473/0x490
> > do_tcp_setsockopt net/ipv4/tcp.c:3614 [inline]
> > tcp_setsockopt+0xda6/0x1be0 net/ipv4/tcp.c:3698
> > sock_common_setsockopt+0x62/0x80 net/core/sock.c:3505
> > __sys_setsockopt+0x2d1/0x450 net/socket.c:2180
> > __do_sys_setsockopt net/socket.c:2191 [inline]
> > __se_sys_setsockopt net/socket.c:2188 [inline]
> > __x64_sys_setsockopt+0x67/0x80 net/socket.c:2188
> > do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> > do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
> > entry_SYSCALL_64_after_hwframe+0x44/0xae
> >
> > read to 0xffffffff883a2438 of 1 bytes by task 6541 on cpu 1:
> > tcp_alloc_md5sig_pool+0x15/0xb0 net/ipv4/tcp.c:4348
> > tcp_md5_do_add+0x2c4/0x470 net/ipv4/tcp_ipv4.c:1199
> > tcp_v4_parse_md5_keys+0x42f/0x500 net/ipv4/tcp_ipv4.c:1303
> > do_tcp_setsockopt net/ipv4/tcp.c:3614 [inline]
> > tcp_setsockopt+0xda6/0x1be0 net/ipv4/tcp.c:3698
> > sock_common_setsockopt+0x62/0x80 net/core/sock.c:3505
> > __sys_setsockopt+0x2d1/0x450 net/socket.c:2180
> > __do_sys_setsockopt net/socket.c:2191 [inline]
> > __se_sys_setsockopt net/socket.c:2188 [inline]
> > __x64_sys_setsockopt+0x67/0x80 net/socket.c:2188
> > do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> > do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
> > entry_SYSCALL_64_after_hwframe+0x44/0xae
> >
> > Reported by Kernel Concurrency Sanitizer on:
> > CPU: 1 PID: 6541 Comm: syz-executor2-n Not tainted 5.18.0-rc5+ #107
> > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
> >
> >
> > Reproducing Inputs
> >
> > Input CPU 0:
> > r0 = socket(0xa, 0x1, 0x0)
> > setsockopt$inet_tcp_TCP_MD5SIG(r0, 0x6, 0xe, &(0x7f0000000000)={@in6={{0xa, 0x0, 0x0, @private0}}, 0x0, 0x0, 0x10, 0x0, "a04979dcb0f6e3666c36f59053376c1d2e245fbad5b4749a8c55dda1bd819ec87afb7f5ac2483f179675d3c23fdba661afcca7cca5661a7b52ac11cc8085800c2c0d8e7de309eb57b89292880a563154"}, 0xd8)
> > setsockopt$inet_tcp_TCP_MD5SIG(r0, 0x6, 0xe, &(0x7f0000000100)={@in6={{0xa, 0x0, 0x0, @loopback}}, 0x0, 0x0, 0x28, 0x0, "f386ea32b026420a2c65ea375667090000000000000000a300001e81f9c22181fe9cef51a4070736c7a33d08c1dd5c35eb9b0e6c6aa490d4f1b18f7b09103bf18619b49a9ce10f4bd98e0b00"}, 0xd8)
> >
> > Input CPU 1:
> > r0 = socket$inet_tcp(0x2, 0x1, 0x0)
> > setsockopt$inet_tcp_TCP_MD5SIG(r0, 0x6, 0xe, &(0x7f0000000080)={@in={{0x2, 0x0, @remote}}, 0x0, 0x0, 0x47, 0x0, "2a34e559cc66f8b453edeb61450c3899cc1d1304f0e5f1758293ddd3597b84447d3056ed871ae397b0fd27a54e4ff8ba83f0cf3e5f323acb74f974c0b87333e0570e9019d8fdcf0bc1044a5e96d68296"}, 0xd8)
