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authorLinus Torvalds <torvalds@linux-foundation.org>2010-02-04 16:07:41 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2010-02-04 16:07:41 -0800
commitaa16cd8d12352ccb5b921995ab3901110779f24a (patch)
treebc93b1e96dda7e1dc6f1aff498767c627f2de638
parenta3a71ca9a715776cf3eda605dafdb4a383782c4f (diff)
parent59647b6ac3050dd964bc556fe6ef22f4db5b935c (diff)
downloadlinux-linaro-stable-aa16cd8d12352ccb5b921995ab3901110779f24a.tar.gz
Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: futex: Handle futex value corruption gracefully futex: Handle user space corruption gracefully futex_lock_pi() key refcnt fix softlockup: Add sched_clock_tick() to avoid kernel warning on kgdb resume
-rw-r--r--include/linux/sched.h4
-rw-r--r--kernel/futex.c30
-rw-r--r--kernel/kgdb.c6
-rw-r--r--kernel/softlockup.c15
4 files changed, 49 insertions, 6 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h
index abdfacc58653..78efe7c485ac 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -310,6 +310,7 @@ extern void sched_show_task(struct task_struct *p);
#ifdef CONFIG_DETECT_SOFTLOCKUP
extern void softlockup_tick(void);
extern void touch_softlockup_watchdog(void);
+extern void touch_softlockup_watchdog_sync(void);
extern void touch_all_softlockup_watchdogs(void);
extern int proc_dosoftlockup_thresh(struct ctl_table *table, int write,
void __user *buffer,
@@ -323,6 +324,9 @@ static inline void softlockup_tick(void)
static inline void touch_softlockup_watchdog(void)
{
}
+static inline void touch_softlockup_watchdog_sync(void)
+{
+}
static inline void touch_all_softlockup_watchdogs(void)
{
}
diff --git a/kernel/futex.c b/kernel/futex.c
index d9b3a2228f9d..e7a35f1039e7 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -530,8 +530,25 @@ lookup_pi_state(u32 uval, struct futex_hash_bucket *hb,
return -EINVAL;
WARN_ON(!atomic_read(&pi_state->refcount));
- WARN_ON(pid && pi_state->owner &&
- pi_state->owner->pid != pid);
+
+ /*
+ * When pi_state->owner is NULL then the owner died
+ * and another waiter is on the fly. pi_state->owner
+ * is fixed up by the task which acquires
+ * pi_state->rt_mutex.
+ *
+ * We do not check for pid == 0 which can happen when
+ * the owner died and robust_list_exit() cleared the
+ * TID.
+ */
+ if (pid && pi_state->owner) {
+ /*
+ * Bail out if user space manipulated the
+ * futex value.
+ */
+ if (pid != task_pid_vnr(pi_state->owner))
+ return -EINVAL;
+ }
atomic_inc(&pi_state->refcount);
*ps = pi_state;
@@ -758,6 +775,13 @@ static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_q *this)
if (!pi_state)
return -EINVAL;
+ /*
+ * If current does not own the pi_state then the futex is
+ * inconsistent and user space fiddled with the futex value.
+ */
+ if (pi_state->owner != current)
+ return -EINVAL;
+
raw_spin_lock(&pi_state->pi_mutex.wait_lock);
new_owner = rt_mutex_next_owner(&pi_state->pi_mutex);
@@ -1971,7 +1995,7 @@ retry_private:
/* Unqueue and drop the lock */
unqueue_me_pi(&q);
- goto out;
+ goto out_put_key;
out_unlock_put_key:
queue_unlock(&q, hb);
diff --git a/kernel/kgdb.c b/kernel/kgdb.c
index c7ade62e4ef0..761fdd2b3034 100644
--- a/kernel/kgdb.c
+++ b/kernel/kgdb.c
@@ -599,7 +599,7 @@ static void kgdb_wait(struct pt_regs *regs)
/* Signal the primary CPU that we are done: */
atomic_set(&cpu_in_kgdb[cpu], 0);
- touch_softlockup_watchdog();
+ touch_softlockup_watchdog_sync();
clocksource_touch_watchdog();
local_irq_restore(flags);
}
@@ -1453,7 +1453,7 @@ acquirelock:
(kgdb_info[cpu].task &&
kgdb_info[cpu].task->pid != kgdb_sstep_pid) && --sstep_tries) {
atomic_set(&kgdb_active, -1);
- touch_softlockup_watchdog();
+ touch_softlockup_watchdog_sync();
clocksource_touch_watchdog();
local_irq_restore(flags);
@@ -1553,7 +1553,7 @@ kgdb_restore:
}
/* Free kgdb_active */
atomic_set(&kgdb_active, -1);
- touch_softlockup_watchdog();
+ touch_softlockup_watchdog_sync();
clocksource_touch_watchdog();
local_irq_restore(flags);
diff --git a/kernel/softlockup.c b/kernel/softlockup.c
index d22579087e27..0d4c7898ab80 100644
--- a/kernel/softlockup.c
+++ b/kernel/softlockup.c
@@ -25,6 +25,7 @@ static DEFINE_SPINLOCK(print_lock);
static DEFINE_PER_CPU(unsigned long, softlockup_touch_ts); /* touch timestamp */
static DEFINE_PER_CPU(unsigned long, softlockup_print_ts); /* print timestamp */
static DEFINE_PER_CPU(struct task_struct *, softlockup_watchdog);
+static DEFINE_PER_CPU(bool, softlock_touch_sync);
static int __read_mostly did_panic;
int __read_mostly softlockup_thresh = 60;
@@ -79,6 +80,12 @@ void touch_softlockup_watchdog(void)
}
EXPORT_SYMBOL(touch_softlockup_watchdog);
+void touch_softlockup_watchdog_sync(void)
+{
+ __raw_get_cpu_var(softlock_touch_sync) = true;
+ __raw_get_cpu_var(softlockup_touch_ts) = 0;
+}
+
void touch_all_softlockup_watchdogs(void)
{
int cpu;
@@ -118,6 +125,14 @@ void softlockup_tick(void)
}
if (touch_ts == 0) {
+ if (unlikely(per_cpu(softlock_touch_sync, this_cpu))) {
+ /*
+ * If the time stamp was touched atomically
+ * make sure the scheduler tick is up to date.
+ */
+ per_cpu(softlock_touch_sync, this_cpu) = false;
+ sched_clock_tick();
+ }
__touch_softlockup_watchdog();
return;
}