From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>, Ingo Molnar <mingo@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
John Stultz <john.stultz@linaro.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
Anna-Maria Behnsen <anna-maria@linutronix.de>
Subject: [patch 05/44] posix-cpu-timers: Sanitize bogus WARNONS
Date: Mon, 19 Aug 2019 16:31:46 +0200 [thread overview]
Message-ID: <20190819143801.846497772@linutronix.de> (raw)
In-Reply-To: 20190819143141.221906747@linutronix.de
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>
---
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) {
next prev parent reply other threads:[~2019-08-19 15:45 UTC|newest]
Thread overview: 83+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-19 14:31 [patch 00/44] posix-cpu-timers: Cleanup and consolidation Thomas Gleixner
2019-08-19 14:31 ` [patch 01/44] posix-timers: Cleanup forward declarations and includes Thomas Gleixner
2019-08-20 12:20 ` Frederic Weisbecker
2019-08-20 13:03 ` Thomas Gleixner
2019-08-20 13:48 ` Frederic Weisbecker
2019-08-23 2:12 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-19 14:31 ` [patch 02/44] alarmtimers: Avoid rtc.h include Thomas Gleixner
2019-08-20 13:49 ` Frederic Weisbecker
2019-08-23 2:12 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-19 14:31 ` [patch 03/44] posix-timer: Use a callback for cancel synchronization Thomas Gleixner
2019-08-20 2:21 ` Christoph Hellwig
2019-08-20 13:08 ` Thomas Gleixner
2019-08-20 13:59 ` Frederic Weisbecker
2019-08-23 2:12 ` [tip: timers/core] posix-timers: Use a callback for cancel synchronization on PREEMPT_RT tip-bot2 for Thomas Gleixner
2019-08-19 14:31 ` [patch 04/44] posix-cpu-timers: Fixup stale comment Thomas Gleixner
2019-08-20 14:26 ` Frederic Weisbecker
2019-08-20 17:57 ` Thomas Gleixner
2019-08-20 20:48 ` Frederic Weisbecker
2019-08-20 21:43 ` Thomas Gleixner
2019-08-20 22:56 ` Frederic Weisbecker
2019-08-21 13:31 ` Thomas Gleixner
2019-08-21 15:51 ` Frederic Weisbecker
2019-08-23 2:12 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-19 14:31 ` Thomas Gleixner [this message]
2019-08-21 11:34 ` [patch 05/44] posix-cpu-timers: Sanitize bogus WARNONS Frederic Weisbecker
2019-08-23 2:12 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-19 14:31 ` [patch 06/44] posix-cpu-timers: Remove tsk argument from run_posix_cpu_timers() Thomas Gleixner
2019-08-21 11:36 ` Frederic Weisbecker
2019-08-23 2:12 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-19 14:31 ` [patch 07/44] posix-cpu-timers: Simplify sighand locking in run_posix_cpu_timers() Thomas Gleixner
2019-08-21 12:09 ` Frederic Weisbecker
2019-08-21 13:25 ` Thomas Gleixner
2019-08-21 15:42 ` Frederic Weisbecker
2019-08-21 17:13 ` Thomas Gleixner
2019-08-19 14:31 ` [patch 08/44] posix-cpu-timers: Provide task validation functions Thomas Gleixner
2019-08-19 14:31 ` [patch 09/44] posix-cpu-timers: Use common permission check in posix_cpu_clock_get() Thomas Gleixner
2019-08-19 14:31 ` [patch 10/44] posix-cpu-timers: Use common permission check in posix_cpu_timer_create() Thomas Gleixner
2019-08-19 14:31 ` [patch 11/44] posix-cpu-timers: Provide quick sample function for itimer Thomas Gleixner
2019-08-19 14:31 ` [patch 12/44] itimers: Use quick sample function Thomas Gleixner
2019-08-19 14:31 ` [patch 13/44] posix-cpu-timers: Sample directly in timer check Thomas Gleixner
2019-08-19 14:31 ` [patch 14/44] posix-cpu-timers: Rename thread_group_cputimer() and make it static Thomas Gleixner
2019-08-19 14:31 ` [patch 15/44] posix-cpu-timer: Comsolidate thread group sample code Thomas Gleixner
2019-08-19 19:07 ` Ingo Molnar
2019-08-19 14:31 ` [patch 16/44] posix-cpu-timers: Use clock ID in posix_cpu_timer_set() Thomas Gleixner
2019-08-19 14:31 ` [patch 17/44] posix-cpu-timers: Use clock ID in posix_cpu_timer_get() Thomas Gleixner
2019-08-19 14:31 ` [patch 18/44] posix-cpu-timers: Use clock ID in posix_cpu_timer_rearm() Thomas Gleixner
2019-08-19 14:32 ` [patch 19/44] posix-cpu-timer: Remove pointless return value check Thomas Gleixner
2019-08-19 14:32 ` [patch 20/44] posix-cpu-timers: Simplify sample functions Thomas Gleixner
2019-08-19 14:32 ` [patch 21/44] posix-cpu-timers: Get rid of pointer indirection Thomas Gleixner
2019-08-19 14:32 ` [patch 22/44] posix-cpu-timers: Sample task times once in expiry check Thomas Gleixner
2019-08-19 14:32 ` [patch 23/44] posix-cpu-timers: Move prof/virt_ticks into caller Thomas Gleixner
2019-08-19 14:32 ` [patch 24/44] posix-cpu-timers: Create a container struct Thomas Gleixner
2019-08-19 14:32 ` [patch 25/44] sched: Move struct task_cputime to types.h Thomas Gleixner
2019-08-19 14:32 ` [patch 26/44] posix-cpu-timers: Move expiry cache into struct posix_cputimers Thomas Gleixner
2019-08-19 14:32 ` [patch 27/44] posix-cpu-timers: Provide array based access to expiry cache Thomas Gleixner
2019-08-19 19:32 ` Ingo Molnar
2019-08-20 20:22 ` Thomas Gleixner
2019-08-19 14:32 ` [patch 28/44] posix-cpu-timers: Simplify timer queueing Thomas Gleixner
2019-08-19 14:32 ` [patch 29/44] posix-cpu-timers: Simplify set_process_cpu_timer() Thomas Gleixner
2019-08-19 14:32 ` [patch 30/44] posix-cpu-timers: Switch check_*_timers() to array cache Thomas Gleixner
2019-08-19 14:32 ` [patch 31/44] posix-cpu-timers: Remove the odd field rename defines Thomas Gleixner
2019-08-19 14:32 ` [patch 32/44] posix-cpu-timers: Provide array based sample functions Thomas Gleixner
2019-08-19 14:32 ` [patch 33/44] posix-cpu-timers: Make expiry checks array based Thomas Gleixner
2019-08-19 14:32 ` [patch 34/44] posix-cpu-timers: Remove cputime_expires Thomas Gleixner
2019-08-19 14:32 ` [patch 35/44] posix-cpu-timers: Switch thread group sampling to array Thomas Gleixner
2019-08-19 14:32 ` [patch 36/44] posix-cpu-timers: Get rid of zero checks Thomas Gleixner
2019-08-19 14:32 ` [patch 37/44] posix-cpu-timers: Consolidate timer expiry further Thomas Gleixner
2019-08-19 14:32 ` [patch 38/44] posix-cpu-timers: Respect INFINITY for hard RTTIME limit Thomas Gleixner
2019-08-19 20:06 ` Ingo Molnar
2019-08-19 20:29 ` Thomas Gleixner
2019-08-19 14:32 ` [patch 39/44] posix-cpu-timers: Get rid of 64bit divisions Thomas Gleixner
2019-08-19 14:32 ` [patch 40/44] posix-cpu-timers: Remove pointless comparisions Thomas Gleixner
2019-08-19 20:10 ` Ingo Molnar
2019-08-19 14:32 ` [patch 41/44] posix-cpu-timers: Deduplicate rlimit handling Thomas Gleixner
2019-08-19 14:32 ` [patch 42/44] posix-cpu-timers: Move state tracking to struct posix_cputimers Thomas Gleixner
2019-08-19 19:13 ` Ingo Molnar
2019-08-19 20:29 ` Thomas Gleixner
2019-08-19 14:32 ` [patch 43/44] posix-cpu-timers: Utilize timerqueue for storage Thomas Gleixner
2019-08-19 14:32 ` [patch 44/44] posix-cpu-timers: Expire timers directly Thomas Gleixner
2019-08-19 19:09 ` Ingo Molnar
2019-08-20 13:07 ` Thomas Gleixner
2019-08-20 2:18 ` [patch 00/44] posix-cpu-timers: Cleanup and consolidation Christoph Hellwig
2019-08-20 13:09 ` Thomas Gleixner
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