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authorLinus Torvalds <torvalds@linux-foundation.org>2014-05-03 08:31:45 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-05-03 08:31:45 -0700
commit98facf0e1ee3d2db313863a283e499ed1c0b5b79 (patch)
tree909bb560a9100ebbc7b7b0e34f47a1357be1ac67 /kernel
parent00622e61eda46c7f8833afbee6bd34449a9a4e7e (diff)
parent98a01e779f3c66b0b11cd7e64d531c0e41c95762 (diff)
downloadlinux-98facf0e1ee3d2db313863a283e499ed1c0b5b79.tar.gz
linux-98facf0e1ee3d2db313863a283e499ed1c0b5b79.tar.xz
Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer fixes from Thomas Gleixner: "This update brings along: - Two fixes for long standing bugs in the hrtimer code, one which prevents remote enqueuing and the other preventing arbitrary delays after a interrupt hang was detected - A fix in the timer wheel which prevents math overflow - A fix for a long standing issue with the architected ARM timer related to the C3STOP mechanism. - A trivial compile fix for nspire SoC clocksource" * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: timer: Prevent overflow in apply_slack hrtimer: Prevent remote enqueue of leftmost timers hrtimer: Prevent all reprogramming if hang detected clocksource: nspire: Fix compiler warning clocksource: arch_arm_timer: Fix age-old arch timer C3STOP detection issue
Diffstat (limited to 'kernel')
-rw-r--r--kernel/hrtimer.c22
-rw-r--r--kernel/timer.c2
2 files changed, 23 insertions, 1 deletions
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index d55092c..6b715c0 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -234,6 +234,11 @@ again:
goto again;
}
timer->base = new_base;
+ } else {
+ if (cpu != this_cpu && hrtimer_check_target(timer, new_base)) {
+ cpu = this_cpu;
+ goto again;
+ }
}
return new_base;
}
@@ -569,6 +574,23 @@ hrtimer_force_reprogram(struct hrtimer_cpu_base *cpu_base, int skip_equal)
cpu_base->expires_next.tv64 = expires_next.tv64;
+ /*
+ * If a hang was detected in the last timer interrupt then we
+ * leave the hang delay active in the hardware. We want the
+ * system to make progress. That also prevents the following
+ * scenario:
+ * T1 expires 50ms from now
+ * T2 expires 5s from now
+ *
+ * T1 is removed, so this code is called and would reprogram
+ * the hardware to 5s from now. Any hrtimer_start after that
+ * will not reprogram the hardware due to hang_detected being
+ * set. So we'd effectivly block all timers until the T2 event
+ * fires.
+ */
+ if (cpu_base->hang_detected)
+ return;
+
if (cpu_base->expires_next.tv64 != KTIME_MAX)
tick_program_event(cpu_base->expires_next, 1);
}
diff --git a/kernel/timer.c b/kernel/timer.c
index 87bd529..3bb01a3 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -838,7 +838,7 @@ unsigned long apply_slack(struct timer_list *timer, unsigned long expires)
bit = find_last_bit(&mask, BITS_PER_LONG);
- mask = (1 << bit) - 1;
+ mask = (1UL << bit) - 1;
expires_limit = expires_limit & ~(mask);