From: Gerd Hoffmann <kraxel@redhat.com>
To: Markus Armbruster <armbru@redhat.com>
Cc: "Marc-André Lureau" <marcandre.lureau@gmail.com>,
"Michael Roth" <mdroth@linux.vnet.ibm.com>,
"Peter Crosthwaite" <crosthwaite.peter@gmail.com>,
qemu-trivial@nongnu.org, "Alexander Graf" <agraf@suse.de>,
qemu-devel@nongnu.org, "Philippe Mathieu-Daudé" <f4bug@amsat.org>
Subject: Re: [Qemu-trivial] [Qemu-devel] [PATCH RESEND 1/3] usb-ccid: make ccid_write_data_block() cope with null buffers
Date: Thu, 23 Mar 2017 14:56:46 +0100 [thread overview]
Message-ID: <1490277406.13302.1.camel@redhat.com> (raw)
In-Reply-To: <87tw6ktban.fsf@dusky.pond.sub.org>
On Do, 2017-03-23 at 13:41 +0100, Markus Armbruster wrote:
> Gerd Hoffmann <kraxel@redhat.com> writes:
>
> > Hi,
> >
> >> oops, there are hard-coded calls with NULL/0. I suppose to fix clang
> >> warning, it would need to check if data != null for memcpy.
> >
> > I'd check for len > 0, and in that if branch we can also assert on data
> > == NULL and thereby check that len and data are consistent.
>
> If len is non-zero but data is null, memcpy() will crash just fine by
> itself, so why bother asserting.
To make clang happy? But maybe clang is clever enough to figure data
can't be null at that point in case we call memcpy with len != 0
only ...
cheers,
Gerd
WARNING: multiple messages have this Message-ID (diff)
From: Gerd Hoffmann <kraxel@redhat.com>
To: Markus Armbruster <armbru@redhat.com>
Cc: "Marc-André Lureau" <marcandre.lureau@gmail.com>,
"Michael Roth" <mdroth@linux.vnet.ibm.com>,
"Peter Crosthwaite" <crosthwaite.peter@gmail.com>,
qemu-trivial@nongnu.org, "Alexander Graf" <agraf@suse.de>,
qemu-devel@nongnu.org, "Philippe Mathieu-Daudé" <f4bug@amsat.org>
Subject: Re: [Qemu-devel] [PATCH RESEND 1/3] usb-ccid: make ccid_write_data_block() cope with null buffers
Date: Thu, 23 Mar 2017 14:56:46 +0100 [thread overview]
Message-ID: <1490277406.13302.1.camel@redhat.com> (raw)
In-Reply-To: <87tw6ktban.fsf@dusky.pond.sub.org>
On Do, 2017-03-23 at 13:41 +0100, Markus Armbruster wrote:
> Gerd Hoffmann <kraxel@redhat.com> writes:
>
> > Hi,
> >
> >> oops, there are hard-coded calls with NULL/0. I suppose to fix clang
> >> warning, it would need to check if data != null for memcpy.
> >
> > I'd check for len > 0, and in that if branch we can also assert on data
> > == NULL and thereby check that len and data are consistent.
>
> If len is non-zero but data is null, memcpy() will crash just fine by
> itself, so why bother asserting.
To make clang happy? But maybe clang is clever enough to figure data
can't be null at that point in case we call memcpy with len != 0
only ...
cheers,
Gerd
next prev parent reply other threads:[~2017-03-23 13:57 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-22 20:48 [Qemu-trivial] [PATCH RESEND 0/3] easy-to-fix clang warnings Philippe Mathieu-Daudé
2017-03-22 20:48 ` [Qemu-devel] " Philippe Mathieu-Daudé
2017-03-22 20:48 ` [Qemu-trivial] [PATCH RESEND 1/3] usb-ccid: make ccid_write_data_block() cope with null buffers Philippe Mathieu-Daudé
2017-03-22 20:48 ` [Qemu-devel] " Philippe Mathieu-Daudé
2017-03-23 6:49 ` [Qemu-trivial] " Markus Armbruster
2017-03-23 6:49 ` Markus Armbruster
2017-03-23 7:43 ` [Qemu-trivial] " Gerd Hoffmann
2017-03-23 7:43 ` Gerd Hoffmann
2017-03-23 8:14 ` [Qemu-trivial] " Marc-André Lureau
2017-03-23 8:14 ` Marc-André Lureau
2017-03-23 9:51 ` [Qemu-trivial] " Gerd Hoffmann
2017-03-23 9:51 ` Gerd Hoffmann
2017-03-23 12:41 ` [Qemu-trivial] " Markus Armbruster
2017-03-23 12:41 ` Markus Armbruster
2017-03-23 13:56 ` Gerd Hoffmann [this message]
2017-03-23 13:56 ` Gerd Hoffmann
2017-03-23 14:08 ` [Qemu-trivial] " Markus Armbruster
2017-03-23 14:08 ` Markus Armbruster
2017-04-07 21:33 ` [Qemu-trivial] " Philippe Mathieu-Daudé
2017-04-07 21:33 ` Philippe Mathieu-Daudé
2017-03-22 20:48 ` [Qemu-trivial] [PATCH RESEND 2/3] device_tree: fix compiler warnings (clang 5) Philippe Mathieu-Daudé
2017-03-22 20:48 ` [Qemu-devel] " Philippe Mathieu-Daudé
2017-03-22 22:35 ` [Qemu-trivial] " Marc-André Lureau
2017-03-22 22:35 ` Marc-André Lureau
2017-03-22 20:48 ` [Qemu-trivial] [PATCH RESEND 3/3] qga: " Philippe Mathieu-Daudé
2017-03-22 20:48 ` [Qemu-devel] " Philippe Mathieu-Daudé
2017-03-22 21:22 ` [Qemu-trivial] " Michael Roth
2017-03-22 21:22 ` [Qemu-devel] " Michael Roth
2017-04-07 21:31 ` [Qemu-trivial] " Philippe Mathieu-Daudé
2017-04-07 21:31 ` Philippe Mathieu-Daudé
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