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Date: Wed, 25 Apr 2012 21:40:36 +0200
From: Dimitry Andric <dim@FreeBSD.org>
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To: Boris Samorodov <bsam@passap.ru>
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Subject: Re: segfault in vfscanf(3): clang and __restrict usage
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On 2012-04-25 21:13, Boris Samorodov wrote:
> 25.04.2012 22:57, Dimitry Andric =D0=BF=D0=B8=D1=88=D0=B5=D1=82:
>> On 2012-04-24 21:49, Jean-S=C3=A9bastien P=C3=A9dron wrote:
>>> Hi everyone,
>>>
>>> vfscanf(3) in HEAD (r234606) segfaults when compiled with clang. For
>>> instance, here is a call made in cmake which crashes:
>>>     fscanf(f, "%*[^\n]\n");
>>
>> Using r234549 here, everything compiled with clang, but I cannot make
>> that statement crash, whatever I do.  Do you have a specific input fil=
e
>> which crashes it?
>=20
> -----
> % uname -a
> FreeBSD bsam.wart.ru 10.0-CURRENT FreeBSD 10.0-CURRENT #0 r234635: Tue
> Apr 24 11:41:32 SAMT 2012     bsam@bsam.wart.ru:/usr/obj/usr/src/sys/BB=
X
>  i386
> % sudo gdb smartd smartd.core
> GNU gdb 6.1.1 [FreeBSD]
> [...]
> #0  0x33ebdc2e in vfscanf () from /lib/libc.so.7
> (gdb)
> -----
>=20
> I think that cupsd also suffer from the bug.
>=20
> BTW, I have the system and almost all ports compiled (tomorrow
> and today) with clang.

Looks like the __restricted keywords were introduced just two days ago,
in r234585, which may be why I didn't see any crashes yet.

I think the easiest solution for now is to #undef __restrict at the top
of both lib/libc/stdio/vfscanf.c and lib/libc/stdio/vfwscanf.c, then
recompile and reinstall libc.