svn commit: r271635 - in head: lib/libc/sys sys/vm

[Konstantin Belousov]

On Wed, Sep 17, 2014 at 11:03:29AM -0400, John Baldwin wrote:
> On Tuesday, September 16, 2014 04:38:21 PM Andriy Gapon wrote:
> > On 15/09/2014 20:20, John Baldwin wrote:
> > > Author: jhb
> > > Date: Mon Sep 15 17:20:13 2014
> > > New Revision: 271635
> > > URL: http://svnweb.freebsd.org/changeset/base/271635
> > > 
> > > Log:
> > >   Add stricter checking of some mmap() arguments:
> > >   - Fail with EINVAL if an invalid protection mask is passed to mmap().
> > >   - Fail with EINVAL if an unknown flag is passed to mmap().
> > >   - Fail with EINVAL if both MAP_PRIVATE and MAP_SHARED are passed to
> > >   mmap().
> > >   - Require one of either MAP_PRIVATE or MAP_SHARED for non-anonymous
> > >   
> > >     mappings.
> > 
> > This broke Java, at least java/openjdk7, for me:
> > 
> >  25323 java     CALL
> > mmap(0,0x3000000,0x3<PROT_READ|PROT_WRITE>,0x1042<MAP_PRIVATE|MAP_NORESERVE|
> > MAP_ANON>,0xffffffff,0) 25323 java     RET   mmap -1 errno 22 Invalid
> > argument
> >  25323 java     CALL  write(0x1,0x7fffffbfd450,0x2b)
> >  25323 java     GIO   fd 1 wrote 43 bytes
> >        "Error occurred during initialization of VM
> >        "
> >  25323 java     RET   write 43/0x2b
> >  25323 java     CALL  write(0x1,0x80209a1e2,0x2d)
> >  25323 java     GIO   fd 1 wrote 45 bytes
> >        "Could not reserve enough space for code cache"
> > 
> > It seems that MAP_NORESERVE presence could be detected in sys/mman.h and
> > then it is used for some reason.
> > I guess that the port can be easily fixed, but this commit breaks
> > compatibility with older binaries.  Perhaps MAP_NORESERVE should be removed
> > as well given that we do not actually implement it.
> 
> I've allowed it for now, but I do intend on removing it in 11.

I think that the removal procedure should be as follows, in the single
commit:
1. remove the defines from public headers, and move them to vm_mmap.c
2. bump __FreeBSD_version
3. allow the bits for older binaries by p_osrel.

Might be, a comment in mman.h should be kept for the binary value
of MAP_NORESERVE so that person who decide to reuse the bit for
a useful flag would be not surprised.
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