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authorLaura Abbott <labbott@redhat.com>2018-04-17 14:57:42 -0700
committerThomas Gleixner <tglx@linutronix.de>2018-04-19 12:54:57 +0200
commitc3bca5d450b620dd3d36e14b5e1f43639fd47d6b (patch)
treed57849e0c5a1fff07dbcaa994d6aaeb80101cdc8 /kernel
parente142aa09ed88be98395dde7acb96fb2263566b68 (diff)
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')
-rw-r--r--kernel/time/posix-cpu-timers.c4
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