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| author | Thomas Gleixner <tglx@linutronix.de> | 2019-08-19 16:31:46 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2019-08-21 20:27:15 +0200 |
| commit | 692117c1f7a6770ed41dd8f277cd9fed1dfb16f1 (patch) | |
| tree | 6ca4c1c027ce037bc2d3a04da36197eea8c1f288 | |
| parent | 68b2c8c1e421096f4b46ac2ac502d25ca067a2a6 (diff) | |
| download | linux-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.c | 20 |
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) { |