linux-kernel - [PATCH] ACPI: Eliminate usage of uninitialized

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: Windows password security audit tool. GUI, reports in PDF.

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

Message-ID: <20200615040047.3535543-1-yanaijie@huawei.com>
Date:   Mon, 15 Jun 2020 12:00:47 +0800
From:   Jason Yan <yanaijie@...wei.com>
To:     <rjw@...ysocki.net>, <lenb@...nel.org>,
        <linux-acpi@...r.kernel.org>, <linux-kernel@...r.kernel.org>
CC:     <kernel-hardening@...ts.openwall.com>,
        Jason Yan <yanaijie@...wei.com>,
        Kees Cook <keescook@...omium.org>
Subject: [PATCH] ACPI: Eliminate usage of uninitialized_var() macro

This is an effort to eliminate the uninitialized_var() macro[1].

The use of this macro is the wrong solution because it forces off ANY
analysis by the compiler for a given variable. It even masks "unused
variable" warnings.

Quoted from Linus[2]:

"It's a horrible thing to use, in that it adds extra cruft to the
source code, and then shuts up a compiler warning (even the _reliable_
warnings from gcc)."

The gcc option "-Wmaybe-uninitialized" has been disabled and this change
will not produce any warnnings even with "make W=1".

[1] https://github.com/KSPP/linux/issues/81
[2] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/

Cc: Kees Cook <keescook@...omium.org>
Signed-off-by: Jason Yan <yanaijie@...wei.com>
---
 drivers/acpi/acpi_pad.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/acpi/acpi_pad.c b/drivers/acpi/acpi_pad.c
index e7dc0133f817..6cc4c92d9ff9 100644
--- a/drivers/acpi/acpi_pad.c
+++ b/drivers/acpi/acpi_pad.c
@@ -88,7 +88,7 @@ static void round_robin_cpu(unsigned int tsk_index)
 	cpumask_var_t tmp;
 	int cpu;
 	unsigned long min_weight = -1;
-	unsigned long uninitialized_var(preferred_cpu);
+	unsigned long preferred_cpu;
 
 	if (!alloc_cpumask_var(&tmp, GFP_KERNEL))
 		return;
-- 
2.25.4