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 <t...@linutronix.de>
---
kernel/time/posix-cpu-timers.c | 20 +++++++++++++-------
1 file changed, 13 insertions(+), 7 deletions(-)
--- 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_
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_
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_
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
*/
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_s
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) {
