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[v2,5/5] ppc: Remove a potential overflow in muldiv64()

Message ID 1462800299-12641-6-git-send-email-lvivier@redhat.com (mailing list archive)
State New, archived
Headers show

Commit Message

Laurent Vivier May 9, 2016, 1:24 p.m. UTC
The coccinelle script:
scripts/coccinelle/overflow_muldiv64.cocci
gives us a list of potential overflows in muldiv64()
(the two first parameters are 64bit values).

This patch fixes one, as the fix seems obvious:

replace muldiv64(a, b, c) by muldiv64(b, a, c)
as "a" and "b" are 64bit values but a <= NANOSECONDS_PER_SECOND.
(10^9 -> 30bit value).

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
---
 hw/ppc/ppc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
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Patch

diff --git a/hw/ppc/ppc.c b/hw/ppc/ppc.c
index 38ff2e1..07ea47c 100644
--- a/hw/ppc/ppc.c
+++ b/hw/ppc/ppc.c
@@ -880,7 +880,7 @@  static int timebase_post_load(void *opaque, int version_id)
     host_ns = qemu_clock_get_ns(QEMU_CLOCK_HOST);
     ns_diff = MAX(0, host_ns - tb_remote->time_of_the_day_ns);
     migration_duration_ns = MIN(NANOSECONDS_PER_SECOND, ns_diff);
-    migration_duration_tb = muldiv64(migration_duration_ns, freq,
+    migration_duration_tb = muldiv64(freq, migration_duration_ns,
                                      NANOSECONDS_PER_SECOND);
     guest_tb = tb_remote->guest_timebase + MIN(0, migration_duration_tb);