== DF-3164: failed MNT_UPDATE leaves mp->mnt_data dangling ==
>> mount good image at /mnt
MOUNT_OK
LS_OK (mount is healthy)
>> failed remount (mount(2) MNT_UPDATE with new fspec=/dev/vn1)
>> expect error 22 EINVAL from the anchor checktag; mount stays live
mount("udf", "/mnt", MNT_RDONLY|MNT_UPDATE, fspec="/dev/vn1") = -1 errno=45 (Operation not supported)
trigger rc=0 (0 = failed remount as expected)
/dev/vn0 on /mnt (udf, read-only, local)
>> triggering UAF: lookup of a never-cached name on the live mount
>> udf_vget -> VFSTOUDFFS(mp)=freed udfmp -> hashtbl[id % hashsz==0]
>> expect divide-by-zero (trap 0) / page-fault panic
/mnt/T25
ls rc=0 (unexpected -- kernel should have panicked here)
SCRIPT_DONE rc=0
--- mount still healthy?
/mnt/T25
FS_STILL_USABLE