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Date:      Tue, 17 Jan 2012 12:12:34 -0500
From:      Eitan Adler <eadler@freebsd.org>
To:        John Baldwin <jhb@freebsd.org>
Cc:        svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org, Colin Percival <cperciva@freebsd.org>
Subject:   Re: svn commit: r230125 - head/sys/kern
Message-ID:  <CAF6rxgngOduQCn_J2bFkn3ExwWbMkbxNbBvqfsWyf3EkNaGrXw@mail.gmail.com>
In-Reply-To: <201201171008.28752.jhb@freebsd.org>
References:  <201201150709.q0F79Iif067938@svn.freebsd.org> <4F136109.9050004@FreeBSD.org> <4F13621B.1060203@freebsd.org> <201201171008.28752.jhb@freebsd.org>

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On Tue, Jan 17, 2012 at 10:08 AM, John Baldwin <jhb@freebsd.org> wrote:
> On Sunday, January 15, 2012 6:32:43 pm Colin Percival wrote:
>> On 01/15/12 15:28, John Baldwin wrote:
>> > On 1/15/12 2:09 AM, Eitan Adler wrote:
>> >> Log:
>> >> =C2=A0 =C2=A0- Fix undefined behavior when device_get_name is null
>> >> =C2=A0 =C2=A0- Make error message more informative
>> >
>> > The in-kernel printf(9) always prints "(null)" for %s when the pointer=
 is NULL,
>> > so that wasn't undefined behavior. =C2=A0Printing out the driver name =
is a useful
>> > change, but the "(unknown)" bits are just noise as it isn't clear that
>> > "(unknown)" is substantially better than "(null)".
>>
>> I think the change from "(null)" to "(unknown)" is useful, since when I =
see
>> "(null)" printed my immediate thought is "looks like there's a bug I nee=
d to
>> track down here".
>
> The entire printf is "there's a bug I need to track down here". =C2=A0(nu=
ll)
> explicitly tells me that device_get_name() is NULL when looking at the pr=
intf
> to see what it means. =C2=A0Having it be (unknown) tells me the same exac=
t thing,
> but only after I've parsed an extra 2-3 lines of code to figure out what
> (unknown) stands for.

To me seeing "(null)" from the output of printf indicates "There is a
bug here, printf should never be given a NULL argument.".
However, given that it isn't undefined here, and the objections I've
received I will revert this part of the change when I get home.


--=20
Eitan Adler
Ports committer
X11, Bugbusting teams



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