From: Jan Kratochvil <jan.kratochvil@redhat.com>
To: Joel Brobecker <brobecker@adacore.com>
Cc: gdb-patches@sourceware.org
Subject: Re: [patch] Fix -fsanitize=address on unreadable inferior strings
Date: Tue, 19 Aug 2014 14:16:00 -0000 [thread overview]
Message-ID: <20140819141601.GA31077@host2.jankratochvil.net> (raw)
In-Reply-To: <20140819065422.GE1773@adacore.com>
On Tue, 19 Aug 2014 08:54:22 +0200, Joel Brobecker wrote:
> > gdb/
> > 2014-08-18 Jan Kratochvil <jan.kratochvil@redhat.com>
> >
> > Fix -fsanitize=address on unreadable inferior strings.
> > * valprint.c (val_print_string): Fix access before BUFFER.
>
> LGTM. I actually don't see why this wouldn't be a possible bug.
> Couldn't LEN be 0, in which case BYTES_READ would be zero, making
> WIDTH > BYTES_READ?
If LEN == 0 then the whole GDB code ignores FOUND_NUL, therefore it is
irrelevant for this patch. Besides that if LEN == 0 then ERRCODE == 0,
therefore FORCE_ELLIPSIS == 0.
A sort of bug is that if the start of string memory is unreadable GDB randomly
may attempt to read the same byte/character second time (failing again).
So it is sort of a performance bug.
(Although such read of the same memory should be cached which I did not check
now if it really is.)
I will therefore check it in.
Jan
next prev parent reply other threads:[~2014-08-19 14:16 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-18 19:27 Jan Kratochvil
2014-08-19 6:54 ` Joel Brobecker
2014-08-19 14:16 ` Jan Kratochvil [this message]
2014-08-19 20:56 ` [commit] " Jan Kratochvil
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