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Tue, 9 Feb 2021 12:30:54 -0500 Received: by smtp.corp.redhat.com (Postfix) id 51C5CA37DF; Tue, 9 Feb 2021 17:30:54 +0000 (UTC) Received: from mimecast-mx02.redhat.com (mimecast04.extmail.prod.ext.rdu2.redhat.com [10.11.55.20]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 4C68D9D51 for ; Tue, 9 Feb 2021 17:30:52 +0000 (UTC) Received: from us-smtp-1.mimecast.com (us-smtp-2.mimecast.com [205.139.110.61]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 03BF3101A58E for ; Tue, 9 Feb 2021 17:30:52 +0000 (UTC) Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-142-jaP58cNGNwe27d8jAgVFvQ-1; Tue, 09 Feb 2021 12:30:49 -0500 X-MC-Unique: jaP58cNGNwe27d8jAgVFvQ-1 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 7594CACB7; Tue, 9 Feb 2021 17:30:48 +0000 (UTC) Message-ID: <11c072c152937004e5f08ecff8dd9ded7d915af6.camel@suse.com> From: Martin Wilck To: lixiaokeng , Benjamin Marzinski , Christophe Varoqui Date: Tue, 09 Feb 2021 18:30:47 +0100 In-Reply-To: <3c8f215a-75d5-0f7b-1008-c8c565bb0cf3@huawei.com> References: <20210128210852.23207-1-mwilck@suse.com> <99488b1b-2339-338d-e951-0b8f3e78449b@huawei.com> <15415073-3b0b-c5a3-ec1d-ced704a42a86@huawei.com> <05408634d2361998782d80b34b7de64d452ba09c.camel@suse.com> <6c80ccbe-0c35-aef8-e95b-97acd06a3487@huawei.com> <7b2c571eb7ff9d54c51037a4fae87796ead1144e.camel@suse.com> <3c8f215a-75d5-0f7b-1008-c8c565bb0cf3@huawei.com> User-Agent: Evolution 3.38.2 MIME-Version: 1.0 X-Mimecast-Impersonation-Protect: Policy=CLT - Impersonation Protection Definition; Similar Internal Domain=false; Similar Monitored External Domain=false; Custom External Domain=false; Mimecast External Domain=false; Newly Observed Domain=false; Internal User Name=false; Custom Display Name List=false; Reply-to Address Mismatch=false; Targeted Threat Dictionary=false; Mimecast Threat Dictionary=false; Custom Threat Dictionary=false X-Mimecast-Bulk-Signature: yes X-Mimecast-Spam-Signature: bulk X-Scanned-By: MIMEDefang 2.79 on 10.11.54.5 X-MIME-Autoconverted: from quoted-printable to 8bit by lists01.pubmisc.prod.ext.phx2.redhat.com id 119HUsMn023664 X-loop: dm-devel@redhat.com Cc: dm-devel@redhat.com Subject: Re: [dm-devel] [PATCH] multipathd: avoid crash in uevent_cleanup() X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dm-devel-bounces@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="iso-8859-15" Content-Transfer-Encoding: quoted-printable On Tue, 2021-02-09 at 09:36 +0800, lixiaokeng wrote: >=20 > >=20 > > I still don't fully understand. Above you said "this coredump > > doesn't > > seem to appear any more". Am I understanding correctly that you > > observed *other* core dumps instead? > >=20 >=20 > No, it is not "instead". > As shown in https://www.spinics.net/lists/dm-devel/msg45293.html, > there are some different crashes in multipathd with no code change. > When blocking of thread cancellation during > udev_monitor_receive_device(), > no crash in udev_monitor_receive_device happens but others still > exist. Now I got it, eventually :-) Thanks for the clarification. Would it be ossible for you to categorize the different=A0issues and provide core dumps? You mentioned in the systemd issue that you were playing around with the gcc -fexceptions flag. As I remarked there - how did it get set in the first place? What distro are you using? > >=20 > > The "best" solution would probably be to generally disallow > > cancellation, and only run pthread_testcancel() at certain points > > in > > the code where we might block (and know that being cancelled would > > be > > safe). That would not only make multipathd safer from crashing, it > > would also enable us to remove hundreds of ugly > > pthread_cleanup_push()/pop() calls from our code. > >=20 > > Finding all these points would be a challenge though, and if we > > don't > > find them, we risk hanging on exit again, which is bad too, and was > > just recently improved. >=20 > Do you mean some patches have been made to solve these problem? No. I could hack up some, but it will take some time. Regards, Martin -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel