On Tue, Mar 12, 2024 at 09:57:58AM +0000, Daniel P. Berrangé wrote:
> On Mon, Mar 11, 2024 at 08:33:35PM -0300, Fabiano Rosas wrote:
> > The file migration code was allowing a possible -1 from a failed call
> > to dup() to propagate into the new QIOFileChannel::fd before checking
> > for validity. Coverity doesn't like that, possibly due to the the
> > lseek(-1, ...) call that would ensue before returning from the channel
> > creation routine.
> >
> > Use the newly introduced qio_channel_file_dupfd() to properly check
> > the return of dup() before proceeding.
> >
> > Fixes: CID 1539961
> > Fixes: CID 1539965
> > Fixes: CID 1539960
> > Fixes: 2dd7ee7a51 ("migration/multifd: Add incoming QIOChannelFile support")
> > Fixes: decdc76772 ("migration/multifd: Add mapped-ram support to fd: URI")
> > Reported-by: Peter Maydell <peter.mayd...@linaro.org>
> > Signed-off-by: Fabiano Rosas <faro...@suse.de>
> > ---
> > migration/fd.c | 9 ++++-----
> > migration/file.c | 14 +++++++-------
> > 2 files changed, 11 insertions(+), 12 deletions(-)
> >
> > diff --git a/migration/fd.c b/migration/fd.c
> > index d4ae72d132..4e2a63a73d 100644
> > --- a/migration/fd.c
> > +++ b/migration/fd.c
> > @@ -80,6 +80,7 @@ static gboolean fd_accept_incoming_migration(QIOChannel
> > *ioc,
> > void fd_start_incoming_migration(const char *fdname, Error **errp)
> > {
> > QIOChannel *ioc;
> > + QIOChannelFile *fioc;
> > int fd = monitor_fd_param(monitor_cur(), fdname, errp);
> > if (fd == -1) {
> > return;
> > @@ -103,15 +104,13 @@ void fd_start_incoming_migration(const char *fdname,
> > Error **errp)
> > int channels = migrate_multifd_channels();
> >
> > while (channels--) {
> > - ioc = QIO_CHANNEL(qio_channel_file_new_fd(dup(fd)));
> > -
> > - if (QIO_CHANNEL_FILE(ioc)->fd == -1) {
> > - error_setg(errp, "Failed to duplicate fd %d", fd);
> > + fioc = qio_channel_file_new_dupfd(fd, errp);
> > + if (!fioc) {
> > return;
> > }
> >
> > qio_channel_set_name(ioc, "migration-fd-incoming");
> > - qio_channel_add_watch_full(ioc, G_IO_IN,
> > + qio_channel_add_watch_full(QIO_CHANNEL(fioc), G_IO_IN,
> > fd_accept_incoming_migration,
> > NULL, NULL,
> >
> > g_main_context_get_thread_default());
>
> Nothing is free'ing the already created channels, if this while()
> loop fails on the 2nd or later iterations.
>
> > diff --git a/migration/file.c b/migration/file.c
> > index 164b079966..d458f48269 100644
> > --- a/migration/file.c
> > +++ b/migration/file.c
> > @@ -58,12 +58,13 @@ bool file_send_channel_create(gpointer opaque, Error
> > **errp)
> > int fd = fd_args_get_fd();
> >
> > if (fd && fd != -1) {
> > - ioc = qio_channel_file_new_fd(dup(fd));
> > + ioc = qio_channel_file_new_dupfd(fd, errp);
> > } else {
> > ioc = qio_channel_file_new_path(outgoing_args.fname, flags, 0,
> > errp);
> > - if (!ioc) {
> > - goto out;
> > - }
> > + }
> > +
> > + if (!ioc) {
> > + goto out;
> > }
> >
> > multifd_channel_connect(opaque, QIO_CHANNEL(ioc));
> > @@ -147,10 +148,9 @@ void file_start_incoming_migration(FileMigrationArgs
> > *file_args, Error **errp)
> > NULL, NULL,
> > g_main_context_get_thread_default());
> >
> > - fioc = qio_channel_file_new_fd(dup(fioc->fd));
> > + fioc = qio_channel_file_new_dupfd(fioc->fd, errp);
> >
> > - if (!fioc || fioc->fd == -1) {
> > - error_setg(errp, "Error creating migration incoming channel");
> > + if (!fioc) {
> > break;
> > }
> > } while (++i < channels);
>
> Again, nothing is free'ing when the loops fails on 2nd or later
> iterations.
For this one, I think it constantly leak one IOC even if no failure
triggers..
>
> So a weak
>
> Reviewed-by: Daniel P. Berrangé <berra...@redhat.com>
>
> on the basis that it fixes the bugs that it claims to fix, but there
> are more bugs that still need fixing here.
For the other issue, Fabiano - I think there's one easy way to workaround
and avoid bothering with "how to remove a registered IO watch" is we create
the IOCs in a loop first, register the IO watches only if all succeeded.
I'll queue the series first to fix the reported issue.
Thanks,
--
Peter Xu
