aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@woody.linux-foundation.org>2008-02-14 21:27:52 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2008-02-14 21:27:52 -0800
commitc24ce1d88781b4d2b8232967630abaa1c90724cf (patch)
tree2de9f0d6f43cdd5135ebaefdd7a77e6326fd66f1
parentf527cf405017e60ceb28f84e2d60ab16fc34f209 (diff)
parent63070a79ba482c274bad10ac8c4b587a3e011f2c (diff)
Merge git://git.kernel.org/pub/scm/linux/kernel/git/tglx/linux-2.6-hrt
* git://git.kernel.org/pub/scm/linux/kernel/git/tglx/linux-2.6-hrt: hrtimer: catch expired CLOCK_REALTIME timers early hrtimer: check relative timeouts for overflow
-rw-r--r--include/linux/ktime.h2
-rw-r--r--kernel/futex.c2
-rw-r--r--kernel/futex_compat.c2
-rw-r--r--kernel/hrtimer.c48
-rw-r--r--kernel/posix-timers.c8
5 files changed, 40 insertions, 22 deletions
diff --git a/include/linux/ktime.h b/include/linux/ktime.h
index 36c542b70c6..2cd7fa73d1a 100644
--- a/include/linux/ktime.h
+++ b/include/linux/ktime.h
@@ -310,6 +310,8 @@ static inline ktime_t ktime_sub_us(const ktime_t kt, const u64 usec)
return ktime_sub_ns(kt, usec * 1000);
}
+extern ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs);
+
/*
* The resolution of the clocks. The resolution value is returned in
* the clock_getres() system call to give application programmers an
diff --git a/kernel/futex.c b/kernel/futex.c
index a6baaec44b8..221f2128a43 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -2116,7 +2116,7 @@ asmlinkage long sys_futex(u32 __user *uaddr, int op, u32 val,
t = timespec_to_ktime(ts);
if (cmd == FUTEX_WAIT)
- t = ktime_add(ktime_get(), t);
+ t = ktime_add_safe(ktime_get(), t);
tp = &t;
}
/*
diff --git a/kernel/futex_compat.c b/kernel/futex_compat.c
index 133d558db45..7d5e4b016f3 100644
--- a/kernel/futex_compat.c
+++ b/kernel/futex_compat.c
@@ -176,7 +176,7 @@ asmlinkage long compat_sys_futex(u32 __user *uaddr, int op, u32 val,
t = timespec_to_ktime(ts);
if (cmd == FUTEX_WAIT)
- t = ktime_add(ktime_get(), t);
+ t = ktime_add_safe(ktime_get(), t);
tp = &t;
}
if (cmd == FUTEX_REQUEUE || cmd == FUTEX_CMP_REQUEUE)
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index 3f4a57c7895..98bee013f71 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -326,6 +326,23 @@ u64 ktime_divns(const ktime_t kt, s64 div)
#endif /* BITS_PER_LONG >= 64 */
/*
+ * Add two ktime values and do a safety check for overflow:
+ */
+ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs)
+{
+ ktime_t res = ktime_add(lhs, rhs);
+
+ /*
+ * We use KTIME_SEC_MAX here, the maximum timeout which we can
+ * return to user space in a timespec:
+ */
+ if (res.tv64 < 0 || res.tv64 < lhs.tv64 || res.tv64 < rhs.tv64)
+ res = ktime_set(KTIME_SEC_MAX, 0);
+
+ return res;
+}
+
+/*
* Check, whether the timer is on the callback pending list
*/
static inline int hrtimer_cb_pending(const struct hrtimer *timer)
@@ -425,6 +442,8 @@ static int hrtimer_reprogram(struct hrtimer *timer,
ktime_t expires = ktime_sub(timer->expires, base->offset);
int res;
+ WARN_ON_ONCE(timer->expires.tv64 < 0);
+
/*
* When the callback is running, we do not reprogram the clock event
* device. The timer callback is either running on a different CPU or
@@ -435,6 +454,15 @@ static int hrtimer_reprogram(struct hrtimer *timer,
if (hrtimer_callback_running(timer))
return 0;
+ /*
+ * CLOCK_REALTIME timer might be requested with an absolute
+ * expiry time which is less than base->offset. Nothing wrong
+ * about that, just avoid to call into the tick code, which
+ * has now objections against negative expiry values.
+ */
+ if (expires.tv64 < 0)
+ return -ETIME;
+
if (expires.tv64 >= expires_next->tv64)
return 0;
@@ -682,13 +710,7 @@ u64 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval)
*/
orun++;
}
- timer->expires = ktime_add(timer->expires, interval);
- /*
- * Make sure, that the result did not wrap with a very large
- * interval.
- */
- if (timer->expires.tv64 < 0)
- timer->expires = ktime_set(KTIME_SEC_MAX, 0);
+ timer->expires = ktime_add_safe(timer->expires, interval);
return orun;
}
@@ -839,7 +861,7 @@ hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
new_base = switch_hrtimer_base(timer, base);
if (mode == HRTIMER_MODE_REL) {
- tim = ktime_add(tim, new_base->get_time());
+ tim = ktime_add_safe(tim, new_base->get_time());
/*
* CONFIG_TIME_LOW_RES is a temporary way for architectures
* to signal that they simply return xtime in
@@ -848,16 +870,8 @@ hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
* timeouts. This will go away with the GTOD framework.
*/
#ifdef CONFIG_TIME_LOW_RES
- tim = ktime_add(tim, base->resolution);
+ tim = ktime_add_safe(tim, base->resolution);
#endif
- /*
- * Careful here: User space might have asked for a
- * very long sleep, so the add above might result in a
- * negative number, which enqueues the timer in front
- * of the queue.
- */
- if (tim.tv64 < 0)
- tim.tv64 = KTIME_MAX;
}
timer->expires = tim;
diff --git a/kernel/posix-timers.c b/kernel/posix-timers.c
index 022c9c3cee6..a9b04203a66 100644
--- a/kernel/posix-timers.c
+++ b/kernel/posix-timers.c
@@ -767,9 +767,11 @@ common_timer_set(struct k_itimer *timr, int flags,
/* SIGEV_NONE timers are not queued ! See common_timer_get */
if (((timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE)) {
/* Setup correct expiry time for relative timers */
- if (mode == HRTIMER_MODE_REL)
- timer->expires = ktime_add(timer->expires,
- timer->base->get_time());
+ if (mode == HRTIMER_MODE_REL) {
+ timer->expires =
+ ktime_add_safe(timer->expires,
+ timer->base->get_time());
+ }
return 0;
}