From: Bruce Cran <bruce@cran.org.uk>
Date: Mon, 20 Feb 2012 06:59:06 +0000 (+0100)
Subject: nice() error handling
X-Git-Tag: fio-2.0.4~24
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=649c10c59b016ae8586e54746d3761bc6df33c9b;p=fio.git

nice() error handling

I've attached a patch which fixes a potential issue I noticed while
reading the POSIX specs: nice() can succeed and return -1, so it's
recommended to set errno to 0 and check it afterwards:

"As -1 is a permissible return value in a successful situation, an
application wishing to check for error situations should set errno to 0,
then call nice(), and if it returns -1, check to see whether errno is
non-zero."

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---

diff --git a/backend.c b/backend.c
index e567ad5e..6e0e4424 100644
--- a/backend.c
+++ b/backend.c
@@ -1019,7 +1019,8 @@ static void *thread_main(void *data)
 	if (td->o.cgroup_weight && cgroup_setup(td, cgroup_list, &cgroup_mnt))
 		goto err;
 
-	if (nice(td->o.nice) == -1) {
+	errno = 0;
+	if (nice(td->o.nice) == -1 && errno != 0) {
 		td_verror(td, errno, "nice");
 		goto err;
 	}