Gave an example for a case where QEMU would try to allocate 0 bytes thus
fail here in the original version of the patch.
> As I mentioned earlier, let's say you don't initialize the vertical
display end registers, and set the minimum scanline register, the emulation
will then have to allocate some display buffer, but because the vertical
display end is initilized as 0 the buffer will be empty and the program
break.
I have no idea as for why my emails are getting messed up... :/
Have to go now, will try and send it again tomorrow probably...
On Tue, May 6, 2025, 19:37 Daniel P. Berrangé <berra...@redhat.com> wrote:
> On Tue, May 06, 2025 at 07:17:25PM +0300, Elisha Hollander wrote:
> > Sorry for former patch something is messed up with my email.
>
> The commit message needs to explain what problem is being solved by
> making this change as allowing 0 bytes looks dubious on the surface.
>
> >
> > Signed-off-by: donno2048 <just4now666...@gmail.com>
> > ---
> > util/memfd.c | 10 ++++++----
> > 1 file changed, 6 insertions(+), 4 deletions(-)
> >
> > diff --git a/util/memfd.c b/util/memfd.c
> > index 8a2e906..e96e5af 100644
> > --- a/util/memfd.c
> > +++ b/util/memfd.c
> > @@ -108,7 +108,7 @@ err:
> > void *qemu_memfd_alloc(const char *name, size_t size, unsigned int
> seals,
> > int *fd, Error **errp)
> > {
> > - void *ptr;
> > + void *ptr = NULL;
> > int mfd = qemu_memfd_create(name, size, false, 0, seals, NULL);
> >
> > /* some systems have memfd without sealing */
> > @@ -131,9 +131,11 @@ void *qemu_memfd_alloc(const char *name, size_t
> size,
> > unsigned int seals,
> > }
> > }
> >
> > - ptr = mmap(0, size, PROT_READ | PROT_WRITE, MAP_SHARED, mfd, 0);
> > - if (ptr == MAP_FAILED) {
> > - goto err;
> > + if (size != 0) {
> > + ptr = mmap(0, size, PROT_READ | PROT_WRITE, MAP_SHARED, mfd, 0);
> > + if (ptr == MAP_FAILED) {
> > + goto err;
> > + }
> > }
>
> This patch is mangled.
>
>
> With regards,
> Daniel
> --
> |: https://berrange.com -o-
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>
>
