migration/vmstate: fix array of ptr with nullptrs
commit07d4e69147b4957e617812206a62a86f03294ad3
authorHalil Pasic <pasic@linux.vnet.ibm.com>
Wed, 22 Feb 2017 16:01:17 +0000 (22 17:01 +0100)
committerDr. David Alan Gilbert <dgilbert@redhat.com>
Tue, 28 Feb 2017 11:29:00 +0000 (28 11:29 +0000)
tree376208699863924fe99aeb027c4e3a4c22f49d89
parentcbfda0e6cfb9d2c7c99b9475bb85ef29f1643ce3
migration/vmstate: fix array of ptr with nullptrs

Make VMS_ARRAY_OF_POINTER cope with null pointers. Previously the
reward for trying to migrate an array with some null pointers in it was
an illegal memory access, that is a swift and painless death of the
process.  Let's make vmstate cope with this scenario.

The general approach is, when we encounter a null pointer (element),
instead of following the pointer to save/load the data behind it, we
save/load a placeholder. This way we can detect if we expected a null
pointer at the load side but not null data was saved instead.

Signed-off-by: Halil Pasic <pasic@linux.vnet.ibm.com>
Reviewed-by: Guenther Hutzl <hutzl@linux.vnet.ibm.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20170222160119.52771-4-pasic@linux.vnet.ibm.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
include/migration/vmstate.h
migration/vmstate.c