diff options
| -rw-r--r-- | include/linux/ktime.h | 2 | ||||
| -rw-r--r-- | kernel/futex.c | 2 | ||||
| -rw-r--r-- | kernel/futex_compat.c | 2 | ||||
| -rw-r--r-- | kernel/hrtimer.c | 48 | ||||
| -rw-r--r-- | kernel/posix-timers.c | 8 |
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; } |