From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44741) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fdrl0-0007K9-7y for qemu-devel@nongnu.org; Fri, 13 Jul 2018 02:40:47 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fdrkz-0002JW-8P for qemu-devel@nongnu.org; Fri, 13 Jul 2018 02:40:46 -0400 References: <20180709154549.7df475b9.cohuck@redhat.com> <20180711130617.GH31228@stefanha-x1.localdomain> <20180711151545.7e55234a.cohuck@redhat.com> <20180711153321.15d2237a.cohuck@redhat.com> <20180712163014.GB23738@stefanha-x1.localdomain> From: Paolo Bonzini Message-ID: Date: Fri, 13 Jul 2018 08:40:19 +0200 MIME-Version: 1.0 In-Reply-To: <20180712163014.GB23738@stefanha-x1.localdomain> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="9vrbD9XlTPMMYMOfKNUHYBW8MUVxYORKR" Subject: Re: [Qemu-devel] qemu-nbd vs 'simple' trace backend vs iotest 147 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stefan Hajnoczi , Cornelia Huck Cc: Stefan Hajnoczi , Kevin Wolf , Max Reitz , qemu-devel@nongnu.org, qemu-block@nongnu.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --9vrbD9XlTPMMYMOfKNUHYBW8MUVxYORKR From: Paolo Bonzini To: Stefan Hajnoczi , Cornelia Huck Cc: Stefan Hajnoczi , Kevin Wolf , Max Reitz , qemu-devel@nongnu.org, qemu-block@nongnu.org Message-ID: Subject: Re: [Qemu-devel] qemu-nbd vs 'simple' trace backend vs iotest 147 References: <20180709154549.7df475b9.cohuck@redhat.com> <20180711130617.GH31228@stefanha-x1.localdomain> <20180711151545.7e55234a.cohuck@redhat.com> <20180711153321.15d2237a.cohuck@redhat.com> <20180712163014.GB23738@stefanha-x1.localdomain> In-Reply-To: <20180712163014.GB23738@stefanha-x1.localdomain> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable On 12/07/2018 18:30, Stefan Hajnoczi wrote: > On Wed, Jul 11, 2018 at 03:33:21PM +0200, Cornelia Huck wrote: >> The other qemu-nbds (the inet and the unix socket ones from the first >> run, the second inet one from the second run) have a single thread wit= h >> the same backtrace I posted above. >=20 > We just discussed this on IRC, but for the record: >=20 > qemu-nbd --fork will fork the process after the simpletrace write-out > thread has been spawned. The child process lacks this thread (due to > how fork(2) handles multithreading). Either qemu-nbd needs to > initialize tracing later (but that means we cannot trace early init) or= > simpletrace needs a way to respawn the write-out thread. You can use pthread_atfork for this. Paolo --9vrbD9XlTPMMYMOfKNUHYBW8MUVxYORKR Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEE8TM4V0tmI4mGbHaCv/vSX3jHroMFAltISVgACgkQv/vSX3jH roN/jAf9EMUJ7USqXfvtvc1T20v7LDx5cANS609FUC9ZuzyPrhQ+f4LSQwLfCtxB GrSed1yBj1aaePGB98RhlMuuRA2AFtqX+QlCOypPKqyoRTYvpQ8YrPUaJzrqEibm QJhWPOzV18DwtNNSXvOCTpTLWtMhUsBTGfCgnlVt5HVjabTXxTRs6jCVzihtK+En 5UE/S2ymrGCPfh285sjTQ0eyd5UDJocTOoex+smoakMKlN9FUgA6/niNrEOOBhJN eL71Y63dPNKa6SAg4Aew7S91fOKmg0PhUNrDk5r7n5AdGEE/c9nolCWsoqL32qvF 48rpHXcgn4LHkkAUTzs70nFGdv/NLw== =lkw7 -----END PGP SIGNATURE----- --9vrbD9XlTPMMYMOfKNUHYBW8MUVxYORKR--