svn commit: r212873 - head/sys/vm
Alan Cox
alc at FreeBSD.org
Sun Sep 19 19:42:05 UTC 2010
Author: alc
Date: Sun Sep 19 19:42:04 2010
New Revision: 212873
URL: http://svn.freebsd.org/changeset/base/212873
Log:
Allow a POSIX shared memory object that is opened for read but not for
write to nonetheless be mapped PROT_WRITE and MAP_PRIVATE, i.e.,
copy-on-write.
(This is a regression in the new implementation of POSIX shared memory
objects that is used by HEAD and RELENG_8. This bug does not exist in
RELENG_7's user-level, file-based implementation.)
PR: 150260
MFC after: 3 weeks
Modified:
head/sys/vm/vm_mmap.c
Modified: head/sys/vm/vm_mmap.c
==============================================================================
--- head/sys/vm/vm_mmap.c Sun Sep 19 19:18:35 2010 (r212872)
+++ head/sys/vm/vm_mmap.c Sun Sep 19 19:42:04 2010 (r212873)
@@ -1373,7 +1373,8 @@ vm_mmap_shm(struct thread *td, vm_size_t
{
int error;
- if ((*maxprotp & VM_PROT_WRITE) == 0 &&
+ if ((*flagsp & MAP_SHARED) != 0 &&
+ (*maxprotp & VM_PROT_WRITE) == 0 &&
(prot & PROT_WRITE) != 0)
return (EACCES);
#ifdef MAC
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