From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-1.6 required=5.0 tests=MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED,RCVD_IN_MSPIKE_H3,RCVD_IN_MSPIKE_WL,URIBL_BLACK autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 8189 invoked from network); 23 Jun 2021 18:32:40 -0000 Received: from mother.openwall.net (195.42.179.200) by inbox.vuxu.org with ESMTPUTF8; 23 Jun 2021 18:32:40 -0000 Received: (qmail 19647 invoked by uid 550); 23 Jun 2021 18:32:37 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Reply-To: musl@lists.openwall.com Received: (qmail 19626 invoked from network); 23 Jun 2021 18:32:36 -0000 Date: Wed, 23 Jun 2021 14:32:24 -0400 From: Rich Felker To: Srinivasan J Cc: musl@lists.openwall.com Message-ID: <20210623183224.GO13220@brightrain.aerifal.cx> References: <20210605155053.GF13220@brightrain.aerifal.cx> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Subject: Re: [musl] Dumping process heap from the core file On Wed, Jun 23, 2021 at 09:21:49AM +0530, Srinivasan J wrote: > Hi Rich, > Thank you for replying. Unfortunately, I need to debug a > core which used musl-libc version v1.1.24 to get details about size of > allocations in the heap. I see that mal.heap is no longer valid since > 2015 [commit e3bc22f1eff87b8f029a6ab31f1a269d69e4b053]. So as you > said the only way to walk the heap would be using a patched libc.so? > Please do share any pointers. Ah, in that case you could just start walking the headers backward/forward from any known starting chunk. Rich > Reference: > https://patchwork.criu.org/patch/10472/ > > Regards, > Srini > > On Sat, Jun 5, 2021 at 9:20 PM Rich Felker wrote: > > > > On Thu, Jun 03, 2021 at 07:39:54AM +0530, Srinivasan J wrote: > > > Hi, > > > Is there an easy way to dump the heap from the process core which > > > is using musl-libc? The process is using musl-libc version v1.1.24. I > > > see that there is a _dump_heap() function, but that's not up to date. > > > I am thinking about using _dump_heap() as reference. But any other > > > suggestions are welcome. > > > > The mallocng heap structures are actually more walkable. There is > > intentionally no public interface for doing this, but I have some > > debug code left over from development that you could link into > > static-linked programs with a particular known musl/mallocng version > > or patch into libc.so for debugging purposes. I'll dig it up and post > > it. Ping me if I forget about it. > > > > Rich