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| author | Thomas Gleixner <tglx@linutronix.de> | 2019-08-19 16:31:46 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-10-05 13:13:45 +0200 |
| commit | de23b986dd21e3a69d7d7df4ce92695e2a5f9ecb (patch) | |
| tree | ecccaa033e8cc520d5c5f9d43752f78cb3abd375 /kernel | |
| parent | 3df4944a75a34ea51fb7a2d490f4132f49b77685 (diff) | |
| download | linux-stable-de23b986dd21e3a69d7d7df4ce92695e2a5f9ecb.tar.gz linux-stable-de23b986dd21e3a69d7d7df4ce92695e2a5f9ecb.tar.bz2 linux-stable-de23b986dd21e3a69d7d7df4ce92695e2a5f9ecb.zip | |
posix-cpu-timers: Sanitize bogus WARNONS
[ Upstream commit 692117c1f7a6770ed41dd8f277cd9fed1dfb16f1 ]
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
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'kernel')
| -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 0a426f4e3125..5bbad147a90c 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/ @@ -580,7 +581,8 @@ 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 @@ -715,10 +717,11 @@ 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. @@ -1000,12 +1003,13 @@ 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. @@ -1202,7 +1206,9 @@ 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) { |