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linux/tools/testing/selftests/ptp
Nick Desaulniers 29f1b2b0fe posix-timers: Prevent UB from shifting negative signed value
Shifting a negative signed number is undefined behavior. Looking at the
macros MAKE_PROCESS_CPUCLOCK and FD_TO_CLOCKID, it seems that the
subexpression:

(~(clockid_t) (pid) << 3)

where clockid_t resolves to a signed int, which once negated, is
undefined behavior to shift the value of if the results thus far are
negative.

It was further suggested to make these macros into inline functions.

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Nick Desaulniers <nick.desaulniers@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Dimitri Sivanich <sivanich@hpe.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-kselftest@vger.kernel.org
Cc: Shuah Khan <shuah@kernel.org>
Cc: Deepa Dinamani <deepa.kernel@gmail.com>
Link: https://lkml.kernel.org/r/1514517100-18051-1-git-send-email-nick.desaulniers@gmail.com
2018-01-04 14:57:10 +01:00
..
.gitignore
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
testptp.c posix-timers: Prevent UB from shifting negative signed value 2018-01-04 14:57:10 +01:00
testptp.mk