Re: [Qemu-devel] [PATCH RFC 1/5] Fix segmentation fault when qemu_signal_init fails

[Fei Li]

On 11/28/2018 08:53 PM, Markus Armbruster wrote:
> Fei Li <address@hidden> writes:
>
> > When qemu_signal_init() fails in qemu_init_main_loop(), we return
> > without setting an error.  Its callers crash then when they try to
> > report the error with error_report_err().
> Yes, that's a bug.  Broken in 2f78e491d7b, v2.2.0.  Has escaped notice
> since qemu_signalfd() is quite unlikely to fail.  Could go into 3.1 as a
> bug fix, but I think punting it to the next release is just fine.
Thanks. :) BTW, should I send the next version only includes patch 1/5
and 2/5 separately so that you can merge? (I guess Dave will help to
merge the other three migration related patches)
> > To avoid such segmentation fault, add a new Error parameter to make
> > the call trace to propagate the err to the final caller.
> Let's add:
>
>    Fixes: 2f78e491d7b46542158ce0b8132ee4e05bc0ade4
ok.
> > Cc: Markus Armbruster <address@hidden>
> > Cc: Fam Zheng <address@hidden>
> > Signed-off-by: Fei Li <address@hidden>
> > Reviewed-by: Fam Zheng <address@hidden>
> > ---
> >   util/main-loop.c | 8 ++++----
> >   1 file changed, 4 insertions(+), 4 deletions(-)
> >
> > diff --git a/util/main-loop.c b/util/main-loop.c
> > index affe0403c5..443cb4cfe8 100644
> > --- a/util/main-loop.c
> > +++ b/util/main-loop.c
> > @@ -71,7 +71,7 @@ static void sigfd_handler(void *opaque)
> >       }
> >   }
> >   
> > -static int qemu_signal_init(void)
> > +static int qemu_signal_init(Error **errp)
> >   {
> >       int sigfd;
> >       sigset_t set;
> > @@ -96,7 +96,7 @@ static int qemu_signal_init(void)
> >       sigdelset(&set, SIG_IPI);
> >       sigfd = qemu_signalfd(&set);
> >       if (sigfd == -1) {
> > -        fprintf(stderr, "failed to create signalfd\n");
> > +        error_setg_errno(errp, errno, "failed to create signalfd");
> >           return -errno;
> >       }
> >   
> > @@ -109,7 +109,7 @@ static int qemu_signal_init(void)
> >   
> >   #else /* _WIN32 */
> >   
> > -static int qemu_signal_init(void)
> > +static int qemu_signal_init(Error **errp)
> >   {
> >       return 0;
> >   }
> > @@ -148,7 +148,7 @@ int qemu_init_main_loop(Error **errp)
> >   
> >       init_clocks(qemu_timer_notify_cb);
> >   
> > -    ret = qemu_signal_init();
> > +    ret = qemu_signal_init(errp);
> >       if (ret) {
> >           return ret;
> >       }
> Reviewed-by: Markus Armbruster <address@hidden>
Thanks again for the review.

Have a nice day
Fei