Commit 692117c1 authored by Thomas Gleixner's avatar Thomas Gleixner

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: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarFrederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190819143801.846497772@linutronix.de
parent 68b2c8c1
......@@ -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) {
......
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