From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39878) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1asyLn-0003IO-T2 for qemu-devel@nongnu.org; Wed, 20 Apr 2016 16:03:52 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1asyLn-0001HW-49 for qemu-devel@nongnu.org; Wed, 20 Apr 2016 16:03:51 -0400 References: <20160413231801.31850.67186.malonedeb@chaenomeles.canonical.com> <20160420000318.17358.96092.malone@soybean.canonical.com> <5717C5F3.90603@redhat.com> From: Max Reitz Message-ID: <5717E09C.5050209@redhat.com> Date: Wed, 20 Apr 2016 22:03:40 +0200 MIME-Version: 1.0 In-Reply-To: <5717C5F3.90603@redhat.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="8TaTTGcNdgd1uPKnEkUSOlfuJonaxpfWH" Subject: Re: [Qemu-devel] [Bug 1570134] Re: While committing snapshot qemu crashes with SIGABRT List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org, Qemu-block , Bug 1570134 <1570134@bugs.launchpad.net> Cc: Paolo Bonzini , Fam Zheng , Stefan Hajnoczi , Kevin Wolf This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --8TaTTGcNdgd1uPKnEkUSOlfuJonaxpfWH Content-Type: multipart/mixed; boundary="UcCuCnuKNp9ewPpi7pM0FBGNbcuJFRpU9" From: Max Reitz To: qemu-devel@nongnu.org, Qemu-block , Bug 1570134 <1570134@bugs.launchpad.net> Cc: Paolo Bonzini , Fam Zheng , Stefan Hajnoczi , Kevin Wolf Message-ID: <5717E09C.5050209@redhat.com> Subject: Re: [Qemu-devel] [Bug 1570134] Re: While committing snapshot qemu crashes with SIGABRT References: <20160413231801.31850.67186.malonedeb@chaenomeles.canonical.com> <20160420000318.17358.96092.malone@soybean.canonical.com> <5717C5F3.90603@redhat.com> In-Reply-To: <5717C5F3.90603@redhat.com> --UcCuCnuKNp9ewPpi7pM0FBGNbcuJFRpU9 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 20.04.2016 20:09, Max Reitz wrote: > On 20.04.2016 02:03, Matthew Schumacher wrote: >> Max, >> >> Qemu still crashes for me, but the debug is again very different. Whe= n >> I attach to the qemu process from gdb, it is unable to provide a >> backtrace when it crashes. The log file is different too. Any ideas?= >> >> qemu-system-x86_64: block.c:2307: bdrv_replace_in_backing_chain: >> Assertion `!bdrv_requests_pending(old)' failed. >=20 > This message is exactly the same as you saw in 2.5.1, so I guess we've > at least averted a regression in 2.6.0. I get the same message in 2.5.0, in 2.4.0 it's "Co-routine re-entered recursively". 2.3.0 works fine. Bisecting the regression between 2.3.0 and 2.4.0 interestingly yields 48ac0a4df84662f as the problematic commit, but I can't imagine that this is the root issue. The effective change it brings is that for active commits, the buf_size is no longer the same as the granularity, but the default mirror buf_size instead. When forcing buf_size to the granularity, the issue first appears with commit 3f09bfbc7bee812 (after 2.4.0, before 2.5.0), which is much less surprising, because this is the one that introduced the assertion in the first place. However, I still don't think the assertion is the problem but the fact that the guest device can still send requests after bdrv_drained_begin().= Max --UcCuCnuKNp9ewPpi7pM0FBGNbcuJFRpU9-- --8TaTTGcNdgd1uPKnEkUSOlfuJonaxpfWH Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQEcBAEBCAAGBQJXF+CcAAoJEDuxQgLoOKyt/xsH/3ZE+rwt0BZqPwRTgvHjVrBF iq7YM+wazJFgSnJgKkutl5tY21ypObsHKOxswL+/yVZPdcA5UVTRBgDZCHSDf28k SP6BdROjbmiLONtNNm9BvDqILta/KLf9zV/a/NFBQfaQQ7zV0UGwcn0eqlI4gut/ Ubf/MgV5yaKoaiQM4AJgZ00TAkZPvbMHiMsAXsO05msE1KtpjCGSGwXy+NcLXxOe OX/6pl3feIe2ZF0O5WMklHG5OFYvdAUjBOUchj3LQ4SC9s8hE/BNcmRQ/RraChEe it2olLGOwRmjNXMPU7Mg7l0ao6imvJE2YI0gTaJYX0Rnr/LI1n/7IaP3Y7iMYHc= =4fSB -----END PGP SIGNATURE----- --8TaTTGcNdgd1uPKnEkUSOlfuJonaxpfWH--