stable inclusion
from linux-4.19.198
commit 1f4c6061fccee64b2072b28dfa3e93cf859c4c0a

--------------------------------

commit d3b16034 upstream.

There's two variables being increased in that loop (i and j), and i
follows the raw data, and j follows what is being written into the buffer.
We should compare 'i' to MAX_MEMHEX_BYTES or compare 'j' to HEX_CHARS.
Otherwise, if 'j' goes bigger than HEX_CHARS, it will overflow the
destination buffer.

Link: https://lore.kernel.org/lkml/20210625122453.5e2fe304@oasis.local.home/
Link: https://lkml.kernel.org/r/20210626032156.47889-1-yun.zhou@windriver.com

Cc: stable@vger.kernel.org
Fixes: 5e3ca0ec ("ftrace: introduce the "hex" output method")
Signed-off-by: NYun Zhou <yun.zhou@windriver.com>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>