From ad9a2faaea4e03a57b29eadabdebab1cbd73a5b3 Mon Sep 17 00:00:00 2001
From: Gal Tashma <gtappsdev@gmail.com>
Date: Tue, 1 Jun 2021 19:02:27 +0300
Subject: [PATCH] don't panick on time subtraction failure (#141)

On some machines, the system clock can be faulty and start_time maybe
actually be after the end time. This causes a panic, instead gracefully
just put a None time in `self.last_runtime`
---
 libafl/src/observers/mod.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libafl/src/observers/mod.rs b/libafl/src/observers/mod.rs
index 803603fce7..b5804b7c8c 100644
--- a/libafl/src/observers/mod.rs
+++ b/libafl/src/observers/mod.rs
@@ -90,7 +90,7 @@ impl<EM, I, S, Z> HasExecHooks<EM, I, S, Z> for TimeObserver {
         _mgr: &mut EM,
         _input: &I,
     ) -> Result<(), Error> {
-        self.last_runtime = Some(current_time() - self.start_time);
+        self.last_runtime = current_time().checked_sub(self.start_time);
         Ok(())
     }
 }