summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorThomas Gleixner <tglx@linutronix.de>2019-08-19 16:31:46 +0200
committerThomas Gleixner <tglx@linutronix.de>2019-08-21 20:27:15 +0200
commit692117c1f7a6770ed41dd8f277cd9fed1dfb16f1 (patch)
tree6ca4c1c027ce037bc2d3a04da36197eea8c1f288
parent68b2c8c1e421096f4b46ac2ac502d25ca067a2a6 (diff)
downloadlinux-692117c1f7a6770ed41dd8f277cd9fed1dfb16f1.tar.gz
linux-692117c1f7a6770ed41dd8f277cd9fed1dfb16f1.tar.bz2
linux-692117c1f7a6770ed41dd8f277cd9fed1dfb16f1.zip
posix-cpu-timers: Sanitize bogus WARNONS
Warning when p == NULL and then proceeding and dereferencing p does not make any sense as the kernel will crash with a NULL pointer dereference right away. Bailing out when p == NULL and returning an error code does not cure the underlying problem which caused p to be NULL. Though it might allow to do proper debugging. Same applies to the clock id check in set_process_cpu_timer(). Clean them up and make them return without trying to do further damage. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Frederic Weisbecker <frederic@kernel.org> Link: https://lkml.kernel.org/r/20190819143801.846497772@linutronix.de
-rw-r--r--kernel/time/posix-cpu-timers.c20
1 files changed, 13 insertions, 7 deletions
diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c
index 742d4a4e6f71..98223d2805c2 100644
--- a/kernel/time/posix-cpu-timers.c
+++ b/kernel/time/posix-cpu-timers.c
@@ -375,7 +375,8 @@ static int posix_cpu_timer_del(struct k_itimer *timer)
struct sighand_struct *sighand;
struct task_struct *p = timer->it.cpu.task;
- WARN_ON_ONCE(p == NULL);
+ if (WARN_ON_ONCE(!p))
+ return -EINVAL;
/*
* Protect against sighand release/switch in exit/exec and process/
@@ -581,7 +582,8 @@ static int posix_cpu_timer_set(struct k_itimer *timer, int timer_flags,
u64 old_expires, new_expires, old_incr, val;
int ret;
- WARN_ON_ONCE(p == NULL);
+ if (WARN_ON_ONCE(!p))
+ return -EINVAL;
/*
* Use the to_ktime conversion because that clamps the maximum
@@ -716,10 +718,11 @@ static int posix_cpu_timer_set(struct k_itimer *timer, int timer_flags,
static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec64 *itp)
{
- u64 now;
struct task_struct *p = timer->it.cpu.task;
+ u64 now;
- WARN_ON_ONCE(p == NULL);
+ if (WARN_ON_ONCE(!p))
+ return;
/*
* Easy part: convert the reload time.
@@ -1001,12 +1004,13 @@ static void check_process_timers(struct task_struct *tsk,
*/
static void posix_cpu_timer_rearm(struct k_itimer *timer)
{
+ struct task_struct *p = timer->it.cpu.task;
struct sighand_struct *sighand;
unsigned long flags;
- struct task_struct *p = timer->it.cpu.task;
u64 now;
- WARN_ON_ONCE(p == NULL);
+ if (WARN_ON_ONCE(!p))
+ return;
/*
* Fetch the current sample and update the timer's expiry time.
@@ -1203,7 +1207,9 @@ void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx,
u64 now;
int ret;
- WARN_ON_ONCE(clock_idx == CPUCLOCK_SCHED);
+ if (WARN_ON_ONCE(clock_idx >= CPUCLOCK_SCHED))
+ return;
+
ret = cpu_timer_sample_group(clock_idx, tsk, &now);
if (oldval && ret != -EINVAL) {