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| author | kib <kib@FreeBSD.org> | 2012-02-11 17:29:07 +0000 |
|---|---|---|
| committer | kib <kib@FreeBSD.org> | 2012-02-11 17:29:07 +0000 |
| commit | dacbfe950a81e3904fb15609934754d23432a328 (patch) | |
| tree | e6a1bc83c2fa78afa49c7d25721b2e04105fc483 /sys/vm/vm_mmap.c | |
| parent | 3e86e21237c556aca42212d457e89b7ca8c54064 (diff) | |
| download | FreeBSD-src-dacbfe950a81e3904fb15609934754d23432a328.zip FreeBSD-src-dacbfe950a81e3904fb15609934754d23432a328.tar.gz | |
Close a race due to dropping of the map lock between creating map entry
for a shared mapping and marking the entry for inheritance.
Other thread might execute vmspace_fork() in between (e.g. by fork(2)),
resulting in the mapping becoming private.
Noted and reviewed by: alc
MFC after: 1 week
Diffstat (limited to 'sys/vm/vm_mmap.c')
| -rw-r--r-- | sys/vm/vm_mmap.c | 10 |
1 files changed, 3 insertions, 7 deletions
diff --git a/sys/vm/vm_mmap.c b/sys/vm/vm_mmap.c index e85b681..4b4996f 100644 --- a/sys/vm/vm_mmap.c +++ b/sys/vm/vm_mmap.c @@ -1517,6 +1517,9 @@ vm_mmap(vm_map_t map, vm_offset_t *addr, vm_size_t size, vm_prot_t prot, docow |= MAP_DISABLE_SYNCER; if (flags & MAP_NOCORE) docow |= MAP_DISABLE_COREDUMP; + /* Shared memory is also shared with children. */ + if (flags & MAP_SHARED) + docow |= MAP_INHERIT_SHARE; if (flags & MAP_STACK) rv = vm_map_stack(map, *addr, size, prot, maxprot, @@ -1536,13 +1539,6 @@ vm_mmap(vm_map_t map, vm_offset_t *addr, vm_size_t size, vm_prot_t prot, * or named anonymous without other references. */ vm_object_deallocate(object); - } else if (flags & MAP_SHARED) { - /* - * Shared memory is also shared with children. - */ - rv = vm_map_inherit(map, *addr, *addr + size, VM_INHERIT_SHARE); - if (rv != KERN_SUCCESS) - (void) vm_map_remove(map, *addr, *addr + size); } /* |
