Re: [PATCH v4] char-socket: initialize reconnect timer only when the timer doesn't start

[Paolo Bonzini <pbonzini@redhat.com>]

Sorry, can you resend this?

I cannot apply it.

Paolo

On 11/05/20 14:39, Li Feng wrote:
> When the disconnect event is triggered in the connecting stage,
> the tcp_chr_disconnect_locked may be called twice.
> 
> The first call:
>     #0  qemu_chr_socket_restart_timer (chr=0x55555582ee90) at chardev/char-socket.c:120
>     #1  0x000055555558e38c in tcp_chr_disconnect_locked (chr=<optimized out>) at chardev/char-socket.c:490
>     #2  0x000055555558e3cd in tcp_chr_disconnect (chr=0x55555582ee90) at chardev/char-socket.c:497
>     #3  0x000055555558ea32 in tcp_chr_new_client (chr=chr@entry=0x55555582ee90, sioc=sioc@entry=0x55555582f0b0) at chardev/char-socket.c:892
>     #4  0x000055555558eeb8 in qemu_chr_socket_connected (task=0x55555582f300, opaque=<optimized out>) at chardev/char-socket.c:1090
>     #5  0x0000555555574352 in qio_task_complete (task=task@entry=0x55555582f300) at io/task.c:196
>     #6  0x00005555555745f4 in qio_task_thread_result (opaque=0x55555582f300) at io/task.c:111
>     #7  qio_task_wait_thread (task=0x55555582f300) at io/task.c:190
>     #8  0x000055555558f17e in tcp_chr_wait_connected (chr=0x55555582ee90, errp=0x555555802a08 <error_abort>) at chardev/char-socket.c:1013
>     #9  0x0000555555567cbd in char_socket_client_reconnect_test (opaque=0x5555557fe020 <client8unix>) at tests/test-char.c:1152
> The second call:
>     #0  0x00007ffff5ac3277 in raise () from /lib64/libc.so.6
>     #1  0x00007ffff5ac4968 in abort () from /lib64/libc.so.6
>     #2  0x00007ffff5abc096 in __assert_fail_base () from /lib64/libc.so.6
>     #3  0x00007ffff5abc142 in __assert_fail () from /lib64/libc.so.6
>     #4  0x000055555558d10a in qemu_chr_socket_restart_timer (chr=0x55555582ee90) at chardev/char-socket.c:125
>     #5  0x000055555558df0c in tcp_chr_disconnect_locked (chr=<optimized out>) at chardev/char-socket.c:490
>     #6  0x000055555558df4d in tcp_chr_disconnect (chr=0x55555582ee90) at chardev/char-socket.c:497
>     #7  0x000055555558e5b2 in tcp_chr_new_client (chr=chr@entry=0x55555582ee90, sioc=sioc@entry=0x55555582f0b0) at chardev/char-socket.c:892
>     #8  0x000055555558e93a in tcp_chr_connect_client_sync (chr=chr@entry=0x55555582ee90, errp=errp@entry=0x7fffffffd178) at chardev/char-socket.c:944
>     #9  0x000055555558ec78 in tcp_chr_wait_connected (chr=0x55555582ee90, errp=0x555555802a08 <error_abort>) at chardev/char-socket.c:1035
>     #10 0x000055555556804b in char_socket_client_test (opaque=0x5555557fe020 <client8unix>) at tests/test-char.c:1023
> 
> Run test/test-char to reproduce this issue.
> 
> test-char: chardev/char-socket.c:125: qemu_chr_socket_restart_timer: Assertion `!s->reconnect_timer' failed.
> 
> Signed-off-by: Li Feng <fengli@smartx.com>
> ---
> v4:
> - remove the wrong patch
> - fix the char_socket_ping_pong to support the reconnect exception test
> 
> v3:
> - add a patch to fix a crash when recvmsg return 0
> - make the tests reproduce the two crash
> 
> v2:
> - add unit test
> 
>  chardev/char-socket.c |  2 +-
>  tests/test-char.c     | 74 +++++++++++++++++++++++++++++++++++++++------------
>  2 files changed, 58 insertions(+), 18 deletions(-)
> 
> diff --git a/chardev/char-socket.c b/chardev/char-socket.c
> index 1f14c2c7c8..d84330b3c9 100644
> --- a/chardev/char-socket.c
> +++ b/chardev/char-socket.c
> @@ -486,7 +486,7 @@ static void tcp_chr_disconnect_locked(Chardev *chr)
>      if (emit_close) {
>          qemu_chr_be_event(chr, CHR_EVENT_CLOSED);
>      }
> -    if (s->reconnect_time) {
> +    if (s->reconnect_time && !s->reconnect_timer) {
>          qemu_chr_socket_restart_timer(chr);
>      }
>  }
> diff --git a/tests/test-char.c b/tests/test-char.c
> index 8d39bdc9fa..d94580c61e 100644
> --- a/tests/test-char.c
> +++ b/tests/test-char.c
> @@ -625,12 +625,14 @@ static void char_udp_test(void)
>  typedef struct {
>      int event;
>      bool got_pong;
> +    CharBackend *be;
>  } CharSocketTestData;
>  
>  
>  #define SOCKET_PING "Hello"
>  #define SOCKET_PONG "World"
>  
> +typedef void (*char_socket_cb)(void *opaque, QEMUChrEvent event);
>  
>  static void
>  char_socket_event(void *opaque, QEMUChrEvent event)
> @@ -639,6 +641,27 @@ char_socket_event(void *opaque, QEMUChrEvent event)
>      data->event = event;
>  }
>  
> +static void
> +char_socket_event_with_error(void *opaque, QEMUChrEvent event)
> +{
> +    static bool first_error;
> +    CharSocketTestData *data = opaque;
> +    CharBackend *be = data->be;
> +    data->event = event;
> +    switch (event) {
> +    case CHR_EVENT_OPENED:
> +        if (!first_error) {
> +            first_error = true;
> +            qemu_chr_fe_disconnect(be);
> +        }
> +        return;
> +    case CHR_EVENT_CLOSED:
> +        return;
> +    default:
> +        return;
> +    }
> +}
> +
>  
>  static void
>  char_socket_read(void *opaque, const uint8_t *buf, int size)
> @@ -699,19 +722,24 @@ char_socket_addr_to_opt_str(SocketAddress *addr, bool fd_pass,
>  }
>  
>  
> -static void
> -char_socket_ping_pong(QIOChannel *ioc)
> +static int
> +char_socket_ping_pong(QIOChannel *ioc, Error **errp)
>  {
>      char greeting[sizeof(SOCKET_PING)];
>      const char *response = SOCKET_PONG;
>  
> -    qio_channel_read_all(ioc, greeting, sizeof(greeting), &error_abort);
> +    int ret;
> +    ret = qio_channel_read_all(ioc, greeting, sizeof(greeting), errp);
> +    if (ret != 0) {
> +        object_unref(OBJECT(ioc));
> +        return -1;
> +    }
>  
>      g_assert(memcmp(greeting, SOCKET_PING, sizeof(greeting)) == 0);
>  
> -    qio_channel_write_all(ioc, response, sizeof(SOCKET_PONG), &error_abort);
> -
> +    qio_channel_write_all(ioc, response, sizeof(SOCKET_PONG), errp);
>      object_unref(OBJECT(ioc));
> +    return 0;
>  }
>  
>  
> @@ -723,7 +751,7 @@ char_socket_server_client_thread(gpointer data)
>  
>      qio_channel_socket_connect_sync(ioc, addr, &error_abort);
>  
> -    char_socket_ping_pong(QIO_CHANNEL(ioc));
> +    char_socket_ping_pong(QIO_CHANNEL(ioc), &error_abort);
>  
>      return NULL;
>  }
> @@ -783,6 +811,7 @@ static void char_socket_server_test(gconstpointer opaque)
>  
>   reconnect:
>      data.event = -1;
> +    data.be = &be;
>      qemu_chr_fe_set_handlers(&be, NULL, NULL,
>                               char_socket_event, NULL,
>                               &data, NULL, true);
> @@ -855,10 +884,13 @@ char_socket_client_server_thread(gpointer data)
>      QIOChannelSocket *ioc = data;
>      QIOChannelSocket *cioc;
>  
> +retry:
>      cioc = qio_channel_socket_accept(ioc, &error_abort);
>      g_assert_nonnull(cioc);
>  
> -    char_socket_ping_pong(QIO_CHANNEL(cioc));
> +    if (char_socket_ping_pong(QIO_CHANNEL(cioc), NULL) != 0) {
> +        goto retry;
> +    }
>  
>      return NULL;
>  }
> @@ -869,6 +901,7 @@ typedef struct {
>      const char *reconnect;
>      bool wait_connected;
>      bool fd_pass;
> +    char_socket_cb event_cb;
>  } CharSocketClientTestConfig;
>  
>  static void char_socket_client_dupid_test(gconstpointer opaque)
> @@ -920,6 +953,7 @@ static void char_socket_client_dupid_test(gconstpointer opaque)
>  static void char_socket_client_test(gconstpointer opaque)
>  {
>      const CharSocketClientTestConfig *config = opaque;
> +    const char_socket_cb event_cb = config->event_cb;
>      QIOChannelSocket *ioc;
>      char *optstr;
>      Chardev *chr;
> @@ -983,8 +1017,9 @@ static void char_socket_client_test(gconstpointer opaque)
>  
>   reconnect:
>      data.event = -1;
> +    data.be = &be;
>      qemu_chr_fe_set_handlers(&be, NULL, NULL,
> -                             char_socket_event, NULL,
> +                             event_cb, NULL,
>                               &data, NULL, true);
>      if (config->reconnect) {
>          g_assert(data.event == -1);
> @@ -1022,7 +1057,7 @@ static void char_socket_client_test(gconstpointer opaque)
>      /* Setup a callback to receive the reply to our greeting */
>      qemu_chr_fe_set_handlers(&be, char_socket_can_read,
>                               char_socket_read,
> -                             char_socket_event, NULL,
> +                             event_cb, NULL,
>                               &data, NULL, true);
>      g_assert(data.event == CHR_EVENT_OPENED);
>      data.event = -1;
> @@ -1467,19 +1502,22 @@ int main(int argc, char **argv)
>  
>  #define SOCKET_CLIENT_TEST(name, addr)                                  \
>      static CharSocketClientTestConfig client1 ## name =                 \
> -        { addr, NULL, false, false };                                   \
> +        { addr, NULL, false, false, char_socket_event};                 \
>      static CharSocketClientTestConfig client2 ## name =                 \
> -        { addr, NULL, true, false };                                    \
> +        { addr, NULL, true, false, char_socket_event };                 \
>      static CharSocketClientTestConfig client3 ## name =                 \
> -        { addr, ",reconnect=1", false };                                \
> +        { addr, ",reconnect=1", false, false, char_socket_event };      \
>      static CharSocketClientTestConfig client4 ## name =                 \
> -        { addr, ",reconnect=1", true };                                 \
> +        { addr, ",reconnect=1", true, false, char_socket_event };       \
>      static CharSocketClientTestConfig client5 ## name =                 \
> -        { addr, NULL, false, true };                                    \
> +        { addr, NULL, false, true, char_socket_event };                 \
>      static CharSocketClientTestConfig client6 ## name =                 \
> -        { addr, NULL, true, true };                                     \
> +        { addr, NULL, true, true, char_socket_event };                  \
>      static CharSocketClientTestConfig client7 ## name =                 \
> -        { addr, ",reconnect=1", false, false };                         \
> +        { addr, ",reconnect=1", false, false, char_socket_event };      \
> +    static CharSocketClientTestConfig client8 ## name =                 \
> +        { addr, ",reconnect=1", true, false,                            \
> +            char_socket_event_with_error };                             \
>      g_test_add_data_func("/char/socket/client/mainloop/" # name,        \
>                           &client1 ##name, char_socket_client_test);     \
>      g_test_add_data_func("/char/socket/client/wait-conn/" # name,       \
> @@ -1493,7 +1531,9 @@ int main(int argc, char **argv)
>      g_test_add_data_func("/char/socket/client/wait-conn-fdpass/" # name, \
>                           &client6 ##name, char_socket_client_test);     \
>      g_test_add_data_func("/char/socket/client/dupid-reconnect/" # name, \
> -                         &client7 ##name, char_socket_client_dupid_test)
> +                         &client7 ##name, char_socket_client_dupid_test);\
> +    g_test_add_data_func("/char/socket/client/reconnect-error/" # name, \
> +                         &client8 ##name, char_socket_client_test)
>  
>      if (has_ipv4) {
>          SOCKET_SERVER_TEST(tcp, &tcpaddr);
>