Re: [PATCH] linux-user: make sure brk(0) returns a page-aligned value

[Helge Deller]

On 7/8/23 23:36, Helge Deller wrote:
> On 7/8/23 19:26, Richard Henderson wrote:
> > On 7/6/23 12:34, Andreas Schwab wrote:
> > > Fixes: 86f04735ac ("linux-user: Fix brk() to release pages")
> > > Signed-off-by: Andreas Schwab <schwab@suse.de>
> > > ---
> > >   linux-user/syscall.c | 2 +-
> > >   1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> > > index 08162cc966..e8a17377f5 100644
> > > --- a/linux-user/syscall.c
> > > +++ b/linux-user/syscall.c
> > > @@ -805,7 +805,7 @@ static abi_ulong brk_page;
> > >   void target_set_brk(abi_ulong new_brk)
> > >   {
> > > -    target_brk = new_brk;
> > > +    target_brk = TARGET_PAGE_ALIGN(new_brk);
> > >       brk_page = HOST_PAGE_ALIGN(target_brk);
> > >   }
> >
> > It make sense, since that's how do_brk aligns things.
>
> Yes, patch looks good.
> I haven't tested, but it seems it adjusts the initial brk(0) value
> only to make sure that it's target page aligned.
> Maybe the title should be: ?
> linux-user: make sure the initial brk(0) is page-aligned

Another bug report regarding the non-aligned brk()...

See:
https://github.com/upx/upx/issues/683
https://gitlab.com/qemu-project/qemu/-/issues/1756

Helge