From: Joe Perches <joe@perches.com>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Ron Mercer <ron.mercer@qlogic.com>,
linux-driver@qlogic.com, netdev <netdev@vger.kernel.org>
Subject: Re: qla3xxx: Odd likely incorrect use of test_bit in qla3xxx.c
Date: Wed, 13 May 2015 10:34:51 -0700 [thread overview]
Message-ID: <1431538491.2912.14.camel@perches.com> (raw)
In-Reply-To: <20150513131908.GB8431@mwanda>
On Wed, 2015-05-13 at 16:19 +0300, Dan Carpenter wrote:
> Good eye, Joe.
>
> I wrote a Smatch check to find similar bugs. Te rhey weren't any other
> places which tried to do bitwise OR. The bug that happens occasionally
> is:
>
> #define MY_FLAG BIT(1)
>
> if (test_bit(MY_FLAG, &map)) {
> ...
>
> It's not normally harmful if it's used consistently, but ath9k had
> memory corruption because they do:
>
> set_bit(BIT(6), &some_unsigned_long);
>
> Anyway, I'll send patches for the bugs I found and push the Smatch
> check. Thanks!
In case the patches you found weren't of this type,
there are other possibly suspicious uses with & like:
drivers/usb/host/ehci-tegra.c: set_bit((wIndex & 0xff) - 1, &ehci->suspended_ports);
next prev parent reply other threads:[~2015-05-13 17:34 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-12 18:42 qla3xxx: Odd likely incorrect use of test_bit in qla3xxx.c Joe Perches
2015-05-13 13:19 ` Dan Carpenter
2015-05-13 16:08 ` Joe Perches
2015-05-13 17:34 ` Joe Perches [this message]
2015-05-14 8:01 ` Dan Carpenter
2015-05-14 8:22 ` Joe Perches
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