On Mon, 2008-04-28 at 09:52 -0700, Jonathan Adams wrote: > On Sun, Apr 27, 2008 at 09:01:55PM -0400, Albert Lee wrote: > > Hi, > > > > I'm trying to fix a problem in Wine that is caused by a shared library > > mapping by the dynamic linker. Wine's memory management facility keeps > > track of where some libraries are mapped and assumes they occupy a > > contiguous range of the process address space. > > > > However, in some cases they are not contiguous. In the following > > example, there is a 56K "hole" (containing a single page?) between > > sections of a library at 7FFB0000. > > > > 7FF20000 448K r-x-- /export/ws/wine/dlls/ntdll/ntdll.dll.so > > 7FF90000 4K rw--- /export/ws/wine/dlls/ntdll/ntdll.dll.so > > 7FF91000 120K r-x-- /export/ws/wine/dlls/ntdll/ntdll.dll.so > > 7FFB0000 4K rw--- > > 7FFBE000 40K rwx-- /export/ws/wine/dlls/ntdll/ntdll.dll.so > > 7FFC8000 72K rwx-- /export/ws/wine/dlls/ntdll/ntdll.dll.so > > Just to make this a tad more explicit: > > start end perms notes > 7ff20000 7ff90000 r-x-- /export/ws/wine/dlls/ntdll/ntdll.dll.so > 7ff90000 7ff91000 rw--- /export/ws/wine/dlls/ntdll/ntdll.dll.so > 7ff91000 7ffaf000 r-x-- /export/ws/wine/dlls/ntdll/ntdll.dll.so > 7ffaf000 7ffb0000 ----- 1k hole > 7ffb0000 7ffb1000 rw--- (new anonymous memory) > 7ffb1000 7ffbe000 ----- 13k hole > 7ffbe000 7ffc8000 r-x-- /export/ws/wine/dlls/ntdll/ntdll.dll.so > 7ffc8000 7ffda000 r-x-- /export/ws/wine/dlls/ntdll/ntdll.dll.so > > > The problem is that an mmap after the library is loaded can occupy that > > "hole", which then appears as an overlapping segment to Wine's memory > > management (http://bugs.winehq.org/attachment.cgi?id=12470 ). > > So there's a 15k "hole", which the OS sees as perfectly valid space to shove a > new MAP_ANON segment. Does that match what you're thinking?
Not sure where the 15k comes from, as the 0xe000 - 0x1000 region would be 52k, but otherwise you're spot on. Thanks, -Albert > > Cheers, > - jonathan > > > What is responsible for this "hole"? Is there a way to prevent it when > > creating the object file for the library? > > > > Thanks! > > > > -Albert > > > > > > _______________________________________________ > > tools-linking mailing list > > tools-linking at opensolaris.org
