pagemap: safe read when reading pagemap page
pagemap: safe read when reading pagemap page

Signed-off-by: Katerina Koukiou <2601125deb717345fbc1a69eaf8ffe9a28fa5fe9@gmail.com>

KKoukiou/criu-remote,KKoukiou/criu-remote,KKoukiou/criu-remote,KKoukiou/criu-remote,KKoukiou/criu-remote,KKoukiou/criu-remote