linux-kernel - [PATCH 4.9 182/223] mfd: arizona: Fix undefined behavior

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

Message-Id: <20190802092249.427081370@linuxfoundation.org>
Date:   Fri,  2 Aug 2019 11:36:47 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Arnd Bergmann <arnd@...db.de>,
        Nathan Chancellor <natechancellor@...il.com>,
        Charles Keepax <ckeepax@...nsource.cirrus.com>,
        Lee Jones <lee.jones@...aro.org>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.9 182/223] mfd: arizona: Fix undefined behavior

[ Upstream commit 5da6cbcd2f395981aa9bfc571ace99f1c786c985 ]

When the driver is used with a subdevice that is disabled in the
kernel configuration, clang gets a little confused about the
control flow and fails to notice that n_subdevs is only
uninitialized when subdevs is NULL, and we check for that,
leading to a false-positive warning:

drivers/mfd/arizona-core.c:1423:19: error: variable 'n_subdevs' is uninitialized when used here
      [-Werror,-Wuninitialized]
                              subdevs, n_subdevs, NULL, 0, NULL);
                                       ^~~~~~~~~
drivers/mfd/arizona-core.c:999:15: note: initialize the variable 'n_subdevs' to silence this warning
        int n_subdevs, ret, i;
                     ^
                      = 0

Ideally, we would rearrange the code to avoid all those early
initializations and have an explicit exit in each disabled case,
but it's much easier to chicken out and add one more initialization
here to shut up the warning.

Signed-off-by: Arnd Bergmann <arnd@...db.de>
Reviewed-by: Nathan Chancellor <natechancellor@...il.com>
Signed-off-by: Charles Keepax <ckeepax@...nsource.cirrus.com>
Signed-off-by: Lee Jones <lee.jones@...aro.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/mfd/arizona-core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mfd/arizona-core.c b/drivers/mfd/arizona-core.c
index 41767f7239bb..0556a9749dbe 100644
--- a/drivers/mfd/arizona-core.c
+++ b/drivers/mfd/arizona-core.c
@@ -1038,7 +1038,7 @@ int arizona_dev_init(struct arizona *arizona)
 	unsigned int reg, val, mask;
 	int (*apply_patch)(struct arizona *) = NULL;
 	const struct mfd_cell *subdevs = NULL;
-	int n_subdevs, ret, i;
+	int n_subdevs = 0, ret, i;
 
 	dev_set_drvdata(arizona->dev, arizona);
 	mutex_init(&arizona->clk_lock);
-- 
2.20.1