linux-kernel - [PATCH 1/4] selftests/cgroup: fix clang build failures for abs() calls

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20240503035105.93280-2-jhubbard@nvidia.com>
Date: Thu,  2 May 2024 20:51:02 -0700
From: John Hubbard <jhubbard@...dia.com>
To: Shuah Khan <shuah@...nel.org>
Cc: Tejun Heo <tj@...nel.org>,
	Zefan Li <lizefan.x@...edance.com>,
	Johannes Weiner <hannes@...xchg.org>,
	Michal Hocko <mhocko@...nel.org>,
	Roman Gushchin <roman.gushchin@...ux.dev>,
	Shakeel Butt <shakeel.butt@...ux.dev>,
	Muchun Song <muchun.song@...ux.dev>,
	Waiman Long <longman@...hat.com>,
	Yosry Ahmed <yosryahmed@...gle.com>,
	Nhat Pham <nphamcs@...il.com>,
	Chengming Zhou <chengming.zhou@...ux.dev>,
	Valentin Obst <kernel@...entinobst.de>,
	linux-kselftest@...r.kernel.org,
	cgroups@...r.kernel.org,
	linux-mm@...ck.org,
	LKML <linux-kernel@...r.kernel.org>,
	llvm@...ts.linux.dev,
	John Hubbard <jhubbard@...dia.com>
Subject: [PATCH 1/4] selftests/cgroup: fix clang build failures for abs() calls

First of all, in order to build with clang at all, one must first apply
Valentin Obst's build fix for LLVM [1]. Once that is done, then when
building with clang, via:

    make LLVM=1 -C tools/testing/selftests

..clang is pickier than gcc, about which version of abs(3) to call,
depending on the argument type:

   int abs(int j);
   long labs(long j);
   long long llabs(long long j);

..and this is causing both build failures and warnings, when running:

    make LLVM=1 -C tools/testing/selftests

Fix this by calling labs() in value_close(), because the arguments are
unambiguously "long" type.

[1] https://lore.kernel.org/all/20240329-selftests-libmk-llvm-rfc-v1-1-2f9ed7d1c49f@valentinobst.de/

Signed-off-by: John Hubbard <jhubbard@...dia.com>
---
 tools/testing/selftests/cgroup/cgroup_util.h | 2 +-
 tools/testing/selftests/cgroup/test_kmem.c   | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/cgroup/cgroup_util.h b/tools/testing/selftests/cgroup/cgroup_util.h
index 1df7f202214a..239633e936df 100644
--- a/tools/testing/selftests/cgroup/cgroup_util.h
+++ b/tools/testing/selftests/cgroup/cgroup_util.h
@@ -18,7 +18,7 @@
  */
 static inline int values_close(long a, long b, int err)
 {
-	return abs(a - b) <= (a + b) / 100 * err;
+	return labs(a - b) <= (a + b) / 100 * err;
 }
 
 extern int cg_find_unified_root(char *root, size_t len);
diff --git a/tools/testing/selftests/cgroup/test_kmem.c b/tools/testing/selftests/cgroup/test_kmem.c
index c82f974b85c9..d21d3d280ca2 100644
--- a/tools/testing/selftests/cgroup/test_kmem.c
+++ b/tools/testing/selftests/cgroup/test_kmem.c
@@ -192,7 +192,7 @@ static int test_kmem_memcg_deletion(const char *root)
 		goto cleanup;
 
 	sum = anon + file + kernel + sock;
-	if (abs(sum - current) < MAX_VMSTAT_ERROR) {
+	if (labs(sum - current) < MAX_VMSTAT_ERROR) {
 		ret = KSFT_PASS;
 	} else {
 		printf("memory.current = %ld\n", current);
@@ -380,7 +380,7 @@ static int test_percpu_basic(const char *root)
 	current = cg_read_long(parent, "memory.current");
 	percpu = cg_read_key_long(parent, "memory.stat", "percpu ");
 
-	if (current > 0 && percpu > 0 && abs(current - percpu) <
+	if (current > 0 && percpu > 0 && labs(current - percpu) <
 	    MAX_VMSTAT_ERROR)
 		ret = KSFT_PASS;
 	else
-- 
2.45.0