From: Kalle Valo <kvalo@codeaurora.org>
To: ga58taw@mytum.de
Cc: Julius Niedworok <julius.n@gmx.net>,
linux-wireless@vger.kernel.org, david@redhat.com,
nc@net.in.tum.de, Johannes Berg <johannes@sipsolutions.net>,
"David S. Miller" <davem@davemloft.net>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH RFC v2] mac80211: debugfs option to force TX status frames
Date: Mon, 11 Mar 2019 16:03:38 +0200 [thread overview]
Message-ID: <87h8c98q4l.fsf@codeaurora.org> (raw)
In-Reply-To: <20190307193045.a7awwn6mycloccq5@mission-control> (ga58taw@mytum.de's message of "Thu, 7 Mar 2019 20:30:45 +0100")
ga58taw@mytum.de writes:
> On Thu, Mar 07, 2019 at 05:42:04PM +0200, Kalle Valo wrote:
>> > + len = scnprintf(buf, sizeof(buf), "%d\n", (int)local->force_tx_status);
>>
>> I wonder about the cast, is it guaranteed that a bool is always of the
>> same size as an int?
>
> Why is this a problem? If a bool is smaller than an int, the compiler
> emits code that will prepend the value of force_tx_status with zeros.
Let's say that a bool is a byte and int is four bytes. If you use "%d" I
would guess that in that case scnprintf() writes 4 bytes, meaning that 3
bytes will be overwriting either padding or some other field in the
struct.
But I'm no compiler expert so I'm not going to argue about this anymore.
I just wanted to point out that that the cast looks dangerous and I
would not do it.
--
Kalle Valo
next prev parent reply other threads:[~2019-03-11 14:03 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-26 9:40 [PATCH RFC] mac80211: Use IFF_ECHO to force delivery of tx_status frames Julius Niedworok
2019-02-26 11:04 ` Oliver Hartkopp
2019-02-26 13:13 ` Julius Niedworok
2019-02-26 13:33 ` Johannes Berg
2019-02-28 9:05 ` Julius Niedworok
2019-03-01 8:32 ` Johannes Berg
2019-03-02 15:16 ` Julius Niedworok
2019-03-06 20:02 ` [PATCH RFC v2] mac80211: debugfs option to force TX status frames Julius Niedworok
2019-03-07 15:42 ` Kalle Valo
2019-03-07 19:30 ` ga58taw
2019-03-11 14:03 ` Kalle Valo [this message]
2019-03-11 14:52 ` Jeremy Sowden
2019-03-19 15:07 ` Julius Niedworok
2019-03-20 12:13 ` Jeremy Sowden
2019-03-28 20:01 ` [PATCH v3] " Julius Niedworok
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