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Thu, 23 Oct 2025 21:06:45 +0000 (UTC) Received: from localhost (unknown [10.2.16.62]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 1CD031955F01; Thu, 23 Oct 2025 21:06:44 +0000 (UTC) Date: Thu, 23 Oct 2025 15:43:06 -0400 From: Stefan Hajnoczi To: Kevin Wolf Cc: qemu-devel@nongnu.org, Aarushi Mehta , Fam Zheng , Stefano Garzarella , Hanna Czenczek , eblake@redhat.com, qemu-block@nongnu.org, hibriansong@gmail.com, Stefan Weil , Paolo Bonzini Subject: Re: [PATCH v4 05/12] aio: remove aio_context_use_g_source() Message-ID: <20251023194306.GA62080@fedora> References: <20250910175703.374499-1-stefanha@redhat.com> <20250910175703.374499-6-stefanha@redhat.com> <20251021191033.GB4837@fedora> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="2hO0Kzqwb5+Ba2Pj" Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 Received-SPF: pass client-ip=170.10.129.124; envelope-from=stefanha@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org --2hO0Kzqwb5+Ba2Pj Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Oct 22, 2025 at 11:02:28AM +0200, Kevin Wolf wrote: > Am 21.10.2025 um 21:10 hat Stefan Hajnoczi geschrieben: > > On Thu, Oct 09, 2025 at 06:59:20PM +0200, Kevin Wolf wrote: > > > Am 09.10.2025 um 17:46 hat Kevin Wolf geschrieben: > > > > Am 10.09.2025 um 19:56 hat Stefan Hajnoczi geschrieben: > > > > > There is no need for aio_context_use_g_source() now that epoll(7)= and > > > > > io_uring(7) file descriptor monitoring works with the glib event = loop. > > > > > AioContext doesn't need to be notified that GSource is being used. > > > > >=20 > > > > > Signed-off-by: Stefan Hajnoczi > > > > > Reviewed-by: Eric Blake > > > >=20 > > > > We should probably mention in the commit message that this causes t= he > > > > default fdmon on Linux to change from poll to io_uring. It's a small > > > > code change, but it makes QEMU use a completely different code path= by > > > > default. > > >=20 > > > Just to make sure, I ran 'make check' after this patch and it's faili= ng > > > for me: > > >=20 > > > 10/401 qemu:qtest+qtest-x86_64 / qtest-x86_64/ahci-test = TIMEOUT 150.02s killed by signal 15 SIGTERM > > > 133/401 qemu:unit / test-aio = TIMEOUT 30.01s killed by signal 15 SIGTERM > > > 137/401 qemu:unit / test-bdrv-drain = TIMEOUT 30.01s killed by signal 15 SIGTERM > > > 142/401 qemu:unit / test-block-iothread = TIMEOUT 30.01s killed by signal 15 SIGTERM > > > 192/401 qemu:doc+rust / rust-bql-rs-doctests = FAIL 0.84s exit status 101 > > > 311/401 qemu:block / io-qcow2-267 = ERROR 3.20s exit status 1 > > > 321/401 qemu:block / io-qcow2-copy-before-write = TIMEOUT 180.01s killed by signal 15 SIGTERM > > >=20 > > > Some of them look unrelated, but I have confirmed that the three unit > > > tests still pass before this patch (and still hang after the complete > > > series). > >=20 > > I can't reproduce these failures, regardless of whether sysctl > > kernel.io_uring_disabled is 0 or 1. > >=20 > > Can you launch the unit tests from your terminal and post the output? > >=20 > > $ cd qemu > > $ build/tests/unit/test-aio >=20 > TAP version 14 > # random seed: R02S48dcdde28634143f18bad3947c52d334 > 1..27 > # Start of aio tests > # Start of bh tests > ok 1 /aio/bh/schedule > ok 2 /aio/bh/schedule10 > ok 3 /aio/bh/cancel > ok 4 /aio/bh/delete > ok 5 /aio/bh/flush > # Start of callback-delete tests > ok 6 /aio/bh/callback-delete/one > ok 7 /aio/bh/callback-delete/many > # End of callback-delete tests > # End of bh tests > # Start of event tests > ok 8 /aio/event/add-remove > ok 9 /aio/event/wait > ok 10 /aio/event/flush > # Start of wait tests > ok 11 /aio/event/wait/no-flush-cb > # End of wait tests > # End of event tests > # Start of timer tests >=20 > > $ build/tests/unit/test-bdrv-drain >=20 > TAP version 14 > # random seed: R02S7d6ba0fc81d5b90d323813d680a30644 > 1..30 > # Start of bdrv-drain tests > ok 1 /bdrv-drain/nested > ok 2 /bdrv-drain/set_aio_context > # Start of driver-cb tests >=20 >=20 > > $ build/tests/unit/test-block-iothread >=20 > TAP version 14 > # random seed: R02Sf81baf68887daa9b86be5c72b99df589 > 1..22 > # Start of sync-op tests > ok 1 /sync-op/pread > ok 2 /sync-op/pwrite > ok 3 /sync-op/preadv > ok 4 /sync-op/pwritev > ok 5 /sync-op/preadv_part > ok 6 /sync-op/pwritev_part > ok 7 /sync-op/pwrite_compressed > ok 8 /sync-op/pwrite_zeroes > ok 9 /sync-op/load_vmstate > ok 10 /sync-op/save_vmstate > ok 11 /sync-op/pdiscard > ok 12 /sync-op/truncate > ok 13 /sync-op/block_status > ok 14 /sync-op/flush > ok 15 /sync-op/check > ok 16 /sync-op/activate > # End of sync-op tests > # Start of attach tests >=20 > > That will show exactly which sub-test case is hanging. > > Other information that might help: your host kernel version and liburing > > version. >=20 > This is a F42 system. >=20 > kernel-6.16.12-200.fc42.x86_64 > liburing-2.9-1.fc42.x86_64 >=20 > If you can't reproduce or find a hypothesis what's happening, I can try > to debug one of the hanging processes. Unfortunately I haven't been able to reproduce it on my system. It's a F42 machine with the same package versions as your machine. The test-aio timer tests look like good candidates for debugging. It is likely that the test is either getting to an infinite do {} while (!aio_poll(ctx, false)) loop or to an aio_poll(ctx, true) call that hangs. Thanks for your help with debugging! Stefan --2hO0Kzqwb5+Ba2Pj Content-Type: application/pgp-signature; name=signature.asc -----BEGIN PGP SIGNATURE----- iQEzBAEBCgAdFiEEhpWov9P5fNqsNXdanKSrs4Grc8gFAmj6hUoACgkQnKSrs4Gr c8jlFAf+PX49R4GzTHcdbTvAOZZiYpk4iSaEsLhlfqy3sLjb6aZSgL9thV6CeYEK MbUG5AXeMqayp341+cL5/JuTmr2RspMhxj8RavdGChpU7xvXIZ2JvE5Fzstf7fVS hrWyQO11GKxm2+3Z1Ar+xpikACl10Yq5cRqrvU/vekQS29IbVYuklLdlPMyJTMbL OyMUV+xos4QNxG6dmZovd1z3ty78HIl4wAhgYa1qVDRcziVH1a8SSaC9ReLhOMBj NmeAW0FOxPiNfhOxH6LYPWZ7IYqoJyDaAuTGVmQTbtJdhK/fXcovepfAOLOcAc8A wtmmG0nCg5ZEfo9CkMAV7B3AAf+Q0w== =KCYW -----END PGP SIGNATURE----- --2hO0Kzqwb5+Ba2Pj--