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Date: Wed, 22 Oct 2014 19:08:00 -0000
From: Jan Kratochvil <jan.kratochvil@redhat.com>
To: Wilfried Goesgens <w.goesgens@arangodb.org>
Cc: gdb@sourceware.org
Subject: Re: GDB Crashes with V8 & JIT debugging
Message-ID: <20141022190823.GA7976@host2.jankratochvil.net>
References: <5447741A.9000000@arangodb.org>
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On Wed, 22 Oct 2014 11:08:42 +0200, Wilfried Goesgens wrote:
> https://code.google.com/p/v8/wiki/GDBJITInterface
[...]
> Dwarf Error: Could not find abbrev number 118 [in module <in-memory>]
> Dwarf Error: Could not find abbrev number 267968 [in module <in-memory>]
> Dwarf Error: Could not find abbrev number 58 [in module <in-memory>]
> Dwarf Error: Could not find abbrev number 112 [in module <in-memory>]
> <many similar errors>
> Segmentation fault (core dumped)

GDB dwarf2read.c is not safe against invalid DWARF, it can easily overrun the
input buffers and crash - a sort of DoS.  The JIT DWARF generator is probably
buggy (which suggest also the "Could not find abbrev" messages above), for GDB
it is (*) sort-of not a bug.

(*) probably; GDB could have some DWARF reading bug but I find it improbable
for this case.


Jan