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-rw-r--r--block/blk-throttle.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 38a881cf97d0..13e4377a8b28 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -723,6 +723,12 @@ static unsigned int calculate_io_allowed(u32 iops_limit,
static u64 calculate_bytes_allowed(u64 bps_limit, unsigned long jiffy_elapsed)
{
+ /*
+ * Can result be wider than 64 bits?
+ * We check against 62, not 64, due to ilog2 truncation.
+ */
+ if (ilog2(bps_limit) + ilog2(jiffy_elapsed) - ilog2(HZ) > 62)
+ return U64_MAX;
return mul_u64_u64_div_u64(bps_limit, (u64)jiffy_elapsed, (u64)HZ);
}