[PATCH 0/3] Fix some issues found by Coverity

John Keeping john at keeping.me.uk
Mon Feb 8 15:16:48 CET 2016

On Mon, Feb 08, 2016 at 02:35:10PM +0100, Jason A. Donenfeld wrote:
> http://git.zx2c4.com/cgit/commit/?id=a8b9ef8c1c68fbb9c89db2d8c12dca38c15e2bfd

I'm not sure that quite goes far enough.  Do you want to add this on

-- >8 --
>From fad329930c9f57e0d75d9094bc70532283bd2b79 Mon Sep 17 00:00:00 2001
From: John Keeping <john at keeping.me.uk>
Date: Mon, 8 Feb 2016 14:12:35 +0000
Subject: [PATCH] ui-stats: cast pointer before checking for zero

We abuse the "void *util" field as a counter and recently started to
cast it to a uintptr_t to avoid risking nasal demons by performing
arithmetic on a void pointer.

However, compilers are also known to do "interesting" things if they
know that a pointer is or isn't NULL.  Make this safer by checking if
the counter (after casting) is non-zero rather than checking if the
pointer is non-null.

Signed-off-by: John Keeping <john at keeping.me.uk>
 ui-stats.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/ui-stats.c b/ui-stats.c
index a9c13fd..8cd9178 100644
--- a/ui-stats.c
+++ b/ui-stats.c
@@ -184,9 +184,9 @@ static void add_commit(struct string_list *authors, struct commit *commit,
 	tmp = xstrdup(period->pretty(date));
 	item = string_list_insert(items, tmp);
-	if (item->util)
-		free(tmp);
 	counter = (uintptr_t *)&item->util;
+	if (*counter)
+		free(tmp);

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