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* 319554f284dd ("inet: don't use sk_v6_rcv_saddr directly") causes bind port regression
@ 2017-09-12 22:35 Laura Abbott
  2017-09-12 23:12 ` Josef Bacik
  0 siblings, 1 reply; 14+ messages in thread
From: Laura Abbott @ 2017-09-12 22:35 UTC (permalink / raw)
  To: Josef Bacik, David S. Miller, Alexey Kuznetsov, Hideaki YOSHIFUJI
  Cc: netdev, linux-kernel, Cole Robinson

[-- Attachment #1: Type: text/plain, Size: 1206 bytes --]

Hi,

Fedora got a bug report 
https://bugzilla.redhat.com/show_bug.cgi?id=1432684 of a regression with 
automatic spice port
assignment. The libvirt team reduced this to the attached test
case run as follows:

In a separate terminal, qemu-kvm -vnc 127.0.0.1:0 to grab port 5900. 
Then do this:

$ gcc bind-collision.c && ./a.out
bind: Address already in use
AF_INET check failed.
$ gcc -D CHECK_IPV6 bind-collision.c && ./a.out
AF_INET6 success
AF_INET success
$ gcc bind-collision.c && ./a.out
AF_INET success

Bisection showed this behavior to be caused by

commit 319554f284dda9f2737d09df82ba3610bd8ddea3
Author: Josef Bacik <jbacik@fb.com>
Date:   Thu Jan 19 17:47:46 2017 -0500

     inet: don't use sk_v6_rcv_saddr directly

     When comparing two sockets we need to use inet6_rcv_saddr so we get 
a NULL
     sk_v6_rcv_saddr if the socket isn't AF_INET6, otherwise our 
comparison function
     can be wrong.

     Fixes: 637bc8b ("inet: reset tb->fastreuseport when adding a 
reuseport sk")
     Signed-off-by: Josef Bacik <jbacik@fb.com>
     Signed-off-by: David S. Miller <davem@davemloft.net>


And reverting fixed both the standalone test case and the spice issue.

Any ideas?

Thanks,
Laura

[-- Attachment #2: bind-collision.c --]
[-- Type: text/x-csrc, Size: 2024 bytes --]

#include <arpa/inet.h>
#include <netinet/in.h>
#include <stdbool.h>
#include <stdio.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>

/* Reproducer for https://bugzilla.redhat.com/show_bug.cgi?id=1432684
   Simply do something like: qemu-kvm -vnc 127.0.0.1:0
 */

#define PORT 5900

int check_port(int family) {
    int fd = -1;
    int reuseaddr = 1;
    int v6only = 1;
    int addrlen;
    int ret = -1;
    bool ipv6 = false;
    struct sockaddr *addr;

    struct sockaddr_in6 addr6 = {
        .sin6_family = AF_INET6,
        .sin6_port = htons(PORT),
        .sin6_addr = in6addr_any
    };
    struct sockaddr_in addr4 = {
        .sin_family = AF_INET,
        .sin_port = htons(PORT),
        .sin_addr.s_addr = htonl(INADDR_ANY)
    };


    if (family == AF_INET6) {
        addr = (struct sockaddr*)&addr6;
        addrlen = sizeof(addr6);
        ipv6 = true;
    } else if (family == AF_INET) {
        addr = (struct sockaddr*)&addr4;
        addrlen = sizeof(addr4);
    } else {
        printf("Unknown family\n");
        goto out;
    }

    if ((fd = socket(family, SOCK_STREAM, 0)) < 0) {
        perror("socket");
        goto out;
    }

    if (ipv6 && setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, (void*)&v6only,
                           sizeof(v6only)) < 0) {
        perror("setsockopt IPV6_V6ONLY");
        goto out;
    }

    if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR,
                   &reuseaddr, sizeof(reuseaddr)) < 0) {
        perror("setsockopt SO_REUSEADDR");
        goto out;
    }

    if (bind(fd, addr, addrlen) < 0) {
        perror("bind");
        goto out;
    }

    ret = 0;
out:
    close(fd);
    return ret;
}

int main(void) {
#ifdef CHECK_IPV6
    if (check_port(AF_INET6) < 0) {
        printf("AF_INET6 check failed.\n");
        return -1;
    }
    printf("AF_INET6 success\n");
#endif

    if (check_port(AF_INET) < 0) {
        printf("AF_INET check failed.\n");
        return -1;
    }
    printf("AF_INET success\n");

    return 0;
}

^ permalink raw reply	[flat|nested] 14+ messages in thread
end of thread, other threads:[~2017-11-13  8:09 UTC | newest]

Thread overview: 14+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2017-09-12 22:35 319554f284dd ("inet: don't use sk_v6_rcv_saddr directly") causes bind port regression Laura Abbott
2017-09-12 23:12 ` Josef Bacik
2017-09-13 15:44   ` Laura Abbott
2017-09-13 17:28     ` Josef Bacik
2017-09-13 17:40       ` Cole Robinson
2017-09-13 19:13         ` Cole Robinson
2017-09-13 19:44           ` Josef Bacik
2017-09-13 22:49             ` Cole Robinson
2017-09-15 17:51               ` Josef Bacik
2017-09-17 13:17                 ` Cole Robinson
2017-09-18  8:02                   ` Marc Haber
2017-11-13  7:36                     ` Marc Haber
2017-09-13 19:47       ` Chuck Ebbert
2017-09-13 20:11         ` Josef Bacik

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