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| author | alc <alc@FreeBSD.org> | 2004-07-28 18:23:08 +0000 |
|---|---|---|
| committer | alc <alc@FreeBSD.org> | 2004-07-28 18:23:08 +0000 |
| commit | 9507df06e35de2ec5980481ede329d5b2c0941d0 (patch) | |
| tree | 2929a41c9a8bd235a7302351b15c3a5067b53e4f /sys/vm | |
| parent | 658e7039ff87b88ebafa1c1f106cdf1219dacd59 (diff) | |
| download | FreeBSD-src-9507df06e35de2ec5980481ede329d5b2c0941d0.zip FreeBSD-src-9507df06e35de2ec5980481ede329d5b2c0941d0.tar.gz | |
Correct a very old error in both vm_object_madvise() (originating in
vm/vm_object.c revision 1.88) and vm_object_sync() (originating in
vm/vm_map.c revision 1.36): When descending a chain of backing objects,
both use the wrong object's backing offset. Consequently, both may
operate on the wrong pages.
Quoting Matt, "This could be responsible for all of the sporatic madvise
oddness that has been reported over the years."
Reviewed by: Matt Dillon
Diffstat (limited to 'sys/vm')
| -rw-r--r-- | sys/vm/vm_object.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/sys/vm/vm_object.c b/sys/vm/vm_object.c index 36d1fb4..feb13aa 100644 --- a/sys/vm/vm_object.c +++ b/sys/vm/vm_object.c @@ -985,9 +985,9 @@ vm_object_sync(vm_object_t object, vm_ooffset_t offset, vm_size_t size, VM_OBJECT_LOCK(object); while ((backing_object = object->backing_object) != NULL) { VM_OBJECT_LOCK(backing_object); + offset += object->backing_object_offset; VM_OBJECT_UNLOCK(object); object = backing_object; - offset += object->backing_object_offset; if (object->size < OFF_TO_IDX(offset + size)) size = IDX_TO_OFF(object->size) - offset; } @@ -1096,9 +1096,9 @@ shadowlookup: if (backing_object == NULL) goto unlock_tobject; VM_OBJECT_LOCK(backing_object); + tpindex += OFF_TO_IDX(tobject->backing_object_offset); VM_OBJECT_UNLOCK(tobject); tobject = backing_object; - tpindex += OFF_TO_IDX(tobject->backing_object_offset); goto shadowlookup; } /* |
