On Tue, Mar 12, 2024 at 08:22:18AM -0400, Peter Xu wrote:
> 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.
Yes, that makes sense as an approach.
With regards,
Daniel
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