2013-06-13 15:16:23

by Tommi Rantala

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Subject: include/net/ipv6.h:408:38: warning: ‘*((void *)&addr+8)’ may be used uninitialized in this function

Hello, I'm seeing the following compiler warnings. Do these make any
sense? I'm doing a x86-64 build.

/build/linux/net/ipv4/tcp_metrics.c: In function ?tcp_peer_is_proven?:
/build/linux/include/net/ipv6.h:408:38: warning: ?*((void *)&addr+8)?
may be used uninitialized in this function [-Wmaybe-uninitialized]
/build/linux/net/ipv4/tcp_metrics.c:211:23: note: ?*((void *)&addr+8)?
was declared here
In file included from /build/linux/include/net/inetpeer.h:15:0,
from /build/linux/net/ipv4/tcp_metrics.c:16:
/build/linux/net/ipv4/tcp_metrics.c: In function ?tcp_tw_remember_stamp?:
/build/linux/include/net/ipv6.h:408:38: warning: ?*((void *)&addr+8)?
may be used uninitialized in this function [-Wmaybe-uninitialized]
/build/linux/net/ipv4/tcp_metrics.c:245:23: note: ?*((void *)&addr+8)?
was declared here

$ gcc --version
gcc (Ubuntu/Linaro 4.7.3-1ubuntu1) 4.7.3
Copyright (C) 2012 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

config:
http://fpaste.org/18443/13711363/

Tommi


2013-06-13 15:39:52

by Eric Dumazet

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Subject: Re: include/net/ipv6.h:408:38: warning: ‘*((void *)&addr+8)’ may be used uninitialized in this function

On Thu, 2013-06-13 at 18:16 +0300, Tommi Rantala wrote:
> Hello, I'm seeing the following compiler warnings. Do these make any
> sense? I'm doing a x86-64 build.

> $ gcc --version
> gcc (Ubuntu/Linaro 4.7.3-1ubuntu1) 4.7.3
> Copyright (C) 2012 Free Software Foundation, Inc.
> This is free software; see the source for copying conditions. There is NO
> warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
>
> config:
> http://fpaste.org/18443/13711363/

Well, what tree are you using ?

2013-06-13 17:20:31

by Tommi Rantala

[permalink] [raw]
Subject: Re: include/net/ipv6.h:408:38: warning: ‘*((void *)&addr+8)’ may be used uninitialized in this function

2013/6/13 Eric Dumazet <[email protected]>:
> On Thu, 2013-06-13 at 18:16 +0300, Tommi Rantala wrote:
>> Hello, I'm seeing the following compiler warnings. Do these make any
>> sense? I'm doing a x86-64 build.
>
>> $ gcc --version
>> gcc (Ubuntu/Linaro 4.7.3-1ubuntu1) 4.7.3
>> Copyright (C) 2012 Free Software Foundation, Inc.
>> This is free software; see the source for copying conditions. There is NO
>> warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
>>
>> config:
>> http://fpaste.org/18443/13711363/
>
> Well, what tree are you using ?

mainline, the warnings are from v3.10-rc5-0-g317ddd2.

They are not new, also visible e.g. in v3.9-0-gc1be5a5.