timers: Prevent base clock rewind when forwarding clock

[cascardo/linux.git] / kernel / time / timer.c

diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index ccf9130..7c446fb 100644 (file)
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -1523,12 +1523,16 @@ u64 get_next_timer_interrupt(unsigned long basej, u64 basem)
        is_max_delta = (nextevt == base->clk + NEXT_TIMER_MAX_DELTA);
        base->next_expiry = nextevt;
        /*
-        * We have a fresh next event. Check whether we can forward the base:
+        * We have a fresh next event. Check whether we can forward the
+        * base. We can only do that when @basej is past base->clk
+        * otherwise we might rewind base->clk.
         */
-       if (time_after(nextevt, jiffies))
-               base->clk = jiffies;
-       else if (time_after(nextevt, base->clk))
-               base->clk = nextevt;
+       if (time_after(basej, base->clk)) {
+               if (time_after(nextevt, basej))
+                       base->clk = basej;
+               else if (time_after(nextevt, base->clk))
+                       base->clk = nextevt;
+       }
 
        if (time_before_eq(nextevt, basej)) {
                expires = basem;