Description: kernel/signal.c: avoid undefined behaviour in kill_something_info
References:
 https://news.ycombinator.com/item?id=2972021
 http://lkml.kernel.org/r/1496670008-59084-1-git-send-email-zhongjiang@huawei.com
Notes:
 bwh> This looks very unlikely to have any security impact in reality.
Bugs:
upstream: released (4.13-rc1) [4ea77014af0d6205b05503d1c7aac6eace11d473]
4.9-upstream-stable: released (4.9.104) [ec1975ac988686eba0f105f87ed0b587da43d384]
3.16-upstream-stable: ignored "Minor issue"
3.2-upstream-stable: ignored "Minor issue"
sid: released (4.13.4-1)
4.9-stretch-security: released (4.9.107-1)
3.16-jessie-security: ignored "Minor issue"
3.2-wheezy-security: ignored "Minor issue"