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From: Jan Kratochvil <jan.kratochvil@redhat.com>
To: Hui Zhu <teawater@gmail.com>
Cc: Tom Tromey <tromey@redhat.com>,
	       gdb-patches ml <gdb-patches@sourceware.org>
Subject: Re: [PATCH] printcmd.c (ui_printf): make internalvar string can be printf and eval when inferior cannot alloc memory
Date: Tue, 06 Sep 2011 13:44:00 -0000	[thread overview]
Message-ID: <20110906085007.GA19880@host1.jankratochvil.net> (raw)
In-Reply-To: <CANFwon0=Trk5i-j4MRPOAXx0AeJaqsZk6Tg052n9_EUEiQ=LrQ@mail.gmail.com>

On Tue, 06 Sep 2011 10:21:53 +0200, Hui Zhu wrote:
> +            if (TYPE_CODE (check_typedef (value_type (val_args[i])))
> +		    == TYPE_CODE_ARRAY)
> +	      fprintf_filtered (stream, current_substring,
> +				(char *) value_contents (val_args[i]));

(gdb) set $a={'a','b'}
(gdb) printf "%s\n",$a
==23392== Invalid read of size 1
==23392==    at: vfprintf (vfprintf.c:1568)
==23392==    by: vasprintf (vasprintf.c:64)
==23392==    by: xstrvprintf (common-utils.c:131)
==23392==    by: vfprintf_maybe_filtered (utils.c:2379)
==23392==    by: vfprintf_filtered (utils.c:2389)
==23392==    by: fprintf_filtered (utils.c:2441)
==23392==    by: ui_printf (printcmd.c:2348)
[...]
==23392==  Address 0xd24bb82 is 0 bytes after a block of size 2 alloc'd
==23392==    at: calloc (vg_replace_malloc.c:467)
==23392==    by: xcalloc (common-utils.c:92)
==23392==    by: xzalloc (common-utils.c:102)
==23392==    by: allocate_value_contents (value.c:690)
==23392==    by: allocate_value (value.c:700)
==23392==    by: value_copy (value.c:1299)
==23392==    by: value_of_internalvar (value.c:1725)
==23392==    by: evaluate_subexp_standard (eval.c:903)
==23392==    by: evaluate_subexp_c (c-lang.c:720)
==23392==    by: evaluate_subexp (eval.c:76)
==23392==    by: evaluate_expression (eval.c:151)
==23392==    by: parse_to_comma_and_eval (eval.c:136)
==23392==    by: ui_printf (printcmd.c:2328)
[...]

The original code was not completely correct in such cases but GDB could not
crash, now it can, I find it as a regression.

I would welcome a testcase.


Thanks,
Jan


  reply	other threads:[~2011-09-06  8:50 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-07-20 10:37 Hui Zhu
2011-07-21 20:43 ` Tom Tromey
2011-08-14 15:10   ` Hui Zhu
2011-08-15 19:06     ` Tom Tromey
2011-08-16  4:58       ` Hui Zhu
2011-08-17 14:38         ` Tom Tromey
2011-08-18  2:54           ` Hui Zhu
2011-08-19 14:15             ` Tom Tromey
2011-09-06  8:50               ` Hui Zhu
2011-09-06 13:44                 ` Jan Kratochvil [this message]
2011-09-07  9:27                   ` Hui Zhu
2011-09-07 10:02                     ` Jan Kratochvil
2011-09-09  7:59                       ` Hui Zhu
2011-09-09 12:32                         ` Jan Kratochvil

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