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-rw-r--r--kernel/hrtimer.c17
1 files changed, 17 insertions, 0 deletions
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index d55092c..e3724fd 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -569,6 +569,23 @@ 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);
}