um: account for the separator in add_arg() bounds checking

add_arg() checks whether command_line and arg fit in the fixed
COMMAND_LINE_SIZE buffer, but when command_line is non-empty it inserts
an additional space before appending arg. The current guard does not
account for that separator, so a non-empty command line can pass the
check and still overflow by one byte.

Count the separator when command_line already contains data.

Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
Link: https://patch.msgid.link/20260330062921.40824-1-pengpeng@iscas.ac.cn
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

0 files changed, 0 insertions, 0 deletions