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| author | Nick Desaulniers <nick.desaulniers@gmail.com> | 2017-12-29 04:11:36 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2018-01-04 14:57:10 +0100 |
| commit | 29f1b2b0fecfae69e31833836f1da3136696eee5 (patch) | |
| tree | 4c299cbdc55a3cc3236e8ef3cc80e6af51ee4a57 /kernel/time/posix-cpu-timers.c | |
| parent | Merge branch 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel... (diff) | |
| download | linux-29f1b2b0fecfae69e31833836f1da3136696eee5.tar.xz linux-29f1b2b0fecfae69e31833836f1da3136696eee5.zip | |
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
Diffstat (limited to 'kernel/time/posix-cpu-timers.c')
| -rw-r--r-- | kernel/time/posix-cpu-timers.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c index 1f27887aa194..cef79ca5bbd5 100644 --- a/kernel/time/posix-cpu-timers.c +++ b/kernel/time/posix-cpu-timers.c @@ -1363,8 +1363,8 @@ static long posix_cpu_nsleep_restart(struct restart_block *restart_block) return do_cpu_nanosleep(which_clock, TIMER_ABSTIME, &t); } -#define PROCESS_CLOCK MAKE_PROCESS_CPUCLOCK(0, CPUCLOCK_SCHED) -#define THREAD_CLOCK MAKE_THREAD_CPUCLOCK(0, CPUCLOCK_SCHED) +#define PROCESS_CLOCK make_process_cpuclock(0, CPUCLOCK_SCHED) +#define THREAD_CLOCK make_thread_cpuclock(0, CPUCLOCK_SCHED) static int process_cpu_clock_getres(const clockid_t which_clock, struct timespec64 *tp) |