commit 9e5f1c19800b808a37fb9815a26d382132c26c3d upstream.

The ram_core.c routines treat przs as circular buffers. When writing a
new crash dump, the old buffer needs to be cleared so that the new dump
doesn't end up in the wrong place (i.e. at the end).

The solution to this problem is to reset the circular buffer state before
writing a new Oops dump.
Signed-off-by: NAleksandr Yashkin <a.yashkin@inango-systems.com>
Signed-off-by: NNikolay Merinov <n.merinov@inango-systems.com>
Signed-off-by: NAriel Gilman <a.gilman@inango-systems.com>
Link: https://lore.kernel.org/r/20191223133816.28155-1-n.merinov@inango-systems.com
Fixes: 896fc1f0 ("pstore/ram: Switch to persistent_ram routines")
Cc: stable@vger.kernel.org
Signed-off-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>