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| author | Laura Abbott <labbott@redhat.com> | 2018-04-17 14:57:42 -0700 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2018-04-19 12:54:57 +0200 |
| commit | c3bca5d450b620dd3d36e14b5e1f43639fd47d6b (patch) | |
| tree | d57849e0c5a1fff07dbcaa994d6aaeb80101cdc8 /kernel/time | |
| parent | e142aa09ed88be98395dde7acb96fb2263566b68 (diff) | |
| download | linux-c3bca5d450b620dd3d36e14b5e1f43639fd47d6b.tar.gz linux-c3bca5d450b620dd3d36e14b5e1f43639fd47d6b.tar.bz2 linux-c3bca5d450b620dd3d36e14b5e1f43639fd47d6b.zip | |
posix-cpu-timers: Ensure set_process_cpu_timer is always evaluated
Commit a9445e47d897 ("posix-cpu-timers: Make set_process_cpu_timer()
more robust") moved the check into the 'if' statement. Unfortunately,
it did so on the right side of an && which means that it may get short
circuited and never evaluated. This is easily reproduced with:
$ cat loop.c
void main() {
struct rlimit res;
/* set the CPU time limit */
getrlimit(RLIMIT_CPU,&res);
res.rlim_cur = 2;
res.rlim_max = 2;
setrlimit(RLIMIT_CPU,&res);
while (1);
}
Which will hang forever instead of being killed. Fix this by pulling the
evaluation out of the if statement but checking the return value instead.
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1568337
Fixes: a9445e47d897 ("posix-cpu-timers: Make set_process_cpu_timer() more robust")
Signed-off-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Cc: "Max R . P . Grossmann" <m@max.pm>
Cc: John Stultz <john.stultz@linaro.org>
Link: https://lkml.kernel.org/r/20180417215742.2521-1-labbott@redhat.com
Diffstat (limited to 'kernel/time')
| -rw-r--r-- | kernel/time/posix-cpu-timers.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c index 2541bd89f20e..5a6251ac6f7a 100644 --- a/kernel/time/posix-cpu-timers.c +++ b/kernel/time/posix-cpu-timers.c @@ -1205,10 +1205,12 @@ void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx, u64 *newval, u64 *oldval) { u64 now; + int ret; WARN_ON_ONCE(clock_idx == CPUCLOCK_SCHED); + ret = cpu_timer_sample_group(clock_idx, tsk, &now); - if (oldval && cpu_timer_sample_group(clock_idx, tsk, &now) != -EINVAL) { + if (oldval && ret != -EINVAL) { /* * We are setting itimer. The *oldval is absolute and we update * it to be relative, *newval argument is relative and we update |