X-Recipient:	archive-cygwin AT delorie DOT com
X-Original-To:	cygwin AT cygwin DOT com
Delivered-To:	cygwin AT cygwin DOT com
DMARC-Filter:	OpenDMARC Filter v1.4.1 sourceware.org CBB843858D32
Authentication-Results:	sourceware.org; dmarc=none (p=none dis=none)
	header.from=dronecode.org.uk
Authentication-Results:	sourceware.org; spf=none smtp.mailfrom=dronecode.org.uk
Authentication-Results:	btinternet.com;
	auth=pass (PLAIN) smtp.auth=jonturney AT btinternet DOT com;
	bimi=skipped
X-SNCR-Rigid:	6139452E3F625DD3
X-Originating-IP:	[81.129.146.151]
X-OWM-Source-IP:	81.129.146.151 (GB)
X-OWM-Env-Sender:	jonturney AT btinternet DOT com
X-VadeSecure-score:	verdict=clean score=0/300, class=clean
X-RazorGate-Vade:	gggruggvucftvghtrhhoucdtuddrgedvfedrfeelvddguddtfecutefuodetggdotefrodftvfcurfhrohhfihhlvgemuceutffkvffkuffjvffgnffgvefqofdpqfgfvfenuceurghilhhouhhtmecufedtudenucesvcftvggtihhpihgvnhhtshculddquddttddmnecujfgurhepkfffgggfuffvfhfhjggtgfesthejredttdefjeenucfhrhhomheplfhonhcuvfhurhhnvgihuceojhhonhdrthhurhhnvgihsegurhhonhgvtghouggvrdhorhhgrdhukheqnecuggftrfgrthhtvghrnhepheefkeekkeehffehveeivdevgeevteelheeileettdfghfeiheekgeejtdfhledunecuffhomhgrihhnpegthihgfihinhdrtghomhdpshhouhhrtggvfigrrhgvrdhorhhgnecukfhppeekuddruddvledrudegiedrudehudenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhephhgvlhhopegludelvddrudeikedruddruddtiegnpdhinhgvthepkedurdduvdelrddugeeirdduhedupdhmrghilhhfrhhomhepjhhonhdrthhurhhnvgihsegurhhonhgvtghouggvrdhorhhgrdhukhdpnhgspghrtghpthhtohepvddprhgtphhtthhopeffrghvihgurdetlhhlshhophhpsegtlhdrtggrmhdrrggtrdhukhdprhgtphhtthhopegthihgfihinhestgihghifihhnrdgtohhm
X-RazorGate-Vade-Verdict:	clean 0
X-RazorGate-Vade-Classification:	clean
Message-ID:	<f4e9c183-a4b5-7c59-c608-9922beb76961@dronecode.org.uk>
Date:	Tue, 18 Oct 2022 20:08:48 +0100
MIME-Version:	1.0
User-Agent:	Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101
	Thunderbird/102.3.3
Subject:	Re: Debugging malloc crash in gdb
To:	David Allsopp <David DOT Allsopp AT cl DOT cam DOT ac DOT uk>,
	The Cygwin Mailing List <cygwin AT cygwin DOT com>
References:	<000001d8e2dd$51be37a0$f53aa6e0$@cl.cam.ac.uk>
From:	Jon Turney <jon DOT turney AT dronecode DOT org DOT uk>
In-Reply-To:	<000001d8e2dd$51be37a0$f53aa6e0$@cl.cam.ac.uk>
X-Spam-Status:	No, score=-3570.3 required=5.0 tests=BAYES_00, FORGED_SPF_HELO,
	KAM_DMARC_STATUS, KAM_LAZY_DOMAIN_SECURITY, NICE_REPLY_A, RCVD_IN_DNSWL_NONE,
	SPF_HELO_PASS, SPF_NONE, TXREP autolearn=no autolearn_force=no version=3.4.6
X-Spam-Checker-Version:	SpamAssassin 3.4.6 (2021-04-09) on
	server2.sourceware.org
X-BeenThere:	cygwin AT cygwin DOT com
X-Mailman-Version:	2.1.29
List-Id:	General Cygwin discussions and problem reports <cygwin.cygwin.com>
List-Unsubscribe:	<https://cygwin.com/mailman/options/cygwin>,
	<mailto:cygwin-request AT cygwin DOT com?subject=unsubscribe>
List-Archive:	<https://cygwin.com/pipermail/cygwin/>
List-Post:	<mailto:cygwin AT cygwin DOT com>
List-Help:	<mailto:cygwin-request AT cygwin DOT com?subject=help>
List-Subscribe:	<https://cygwin.com/mailman/listinfo/cygwin>,
	<mailto:cygwin-request AT cygwin DOT com?subject=subscribe>
Errors-To:	cygwin-bounces+archive-cygwin=delorie DOT com AT cygwin DOT com
Sender:	"Cygwin" <cygwin-bounces+archive-cygwin=delorie DOT com AT cygwin DOT com>

On 18/10/2022 11:35, David Allsopp wrote:
> I'm wondering if I may be able to have some pointers for debugging what
> seems to be an unexpected interaction between mmap/mprotect/munmap and
> malloc with the OCaml runtime.
> 
> At the moment, I know that we crash in malloc, so my main question is how to
> go further in gdb. I installed the cygwin-debuginfo package, but all I'm
> getting is:

Firstly, if the crash is inside the cygwin DLL, you must follow the 
advice in [1], and use 'set cygwin-exceptions on' to tell gdb to stop on 
an exception inside cygwin itself.

[1] https://cygwin.com/faq.html#faq.programming.debugging-cygwin


> /cygdrive/d/a/scallywag/gdb/gdb-11.2-1.x86_64/src/gdb-11.2/gdb/infrun.c:2550
> : internal-error: void resume_1(gdb_signal): Assertion
> `pc_in_thread_step_range (pc, tp)' failed.

This looks similar to the gdb crash reported [2], which I just don't 
have any time to look into.

[2] https://cygwin.com/pipermail/cygwin/2022-June/251714.html

I'd suggest reporting this as directed in 
https://www.sourceware.org/gdb/bugs/

(Note that self-service account creation is disabled on the sourceware 
bugzilla, due to spam problems, so you need to mail overseers as 
directed there, to request a Sourceware Bugzilla account.)

> The reproduction case is below (it's the OCaml runtime, so it's not exactly
> minimal, but it seems to be very repeatable to get gdb to the position of
> the crash).
> 
[...]
> 
> Any assistance to debug this further hugely appreciated!

It might be worth exploring if this gdb crash is seen in older versions 
of gcc, or with older gcc...


-- 
Problem reports:      https://cygwin.com/problems.html
FAQ:                  https://cygwin.com/faq/
Documentation:        https://cygwin.com/docs.html
Unsubscribe info:     https://cygwin.com/ml/#unsubscribe-simple

- Raw text -