Good catch, thanks stefanha for your kindly reminds with such good tools (git-bisect) to determine which commit caused this problem. I'm very sorry that i did not try it as your instruction timely, mainly that i focus on the openstack(nova&cinder) currently in the new company and have to adapt to the new work flow & role as quickly as possible. According to me trying that 05e514b1d4d5bd4209e2c8bbc76ff05c85a235f3 is the first bad commit pushed by pbonzini.
My trying results as following: master 074a992 Merge remote-tracking branch 'remotes/cody/tags/block-pull-request' into staging <---> latest version fail qemu-2.3-stable dfa83a6 Update version for 2.3.1 release <---> qemu-2.3-stable good [root@PEK1000012301 qemu]# git bisect start [root@PEK1000012301 qemu]# git bisect bad 074a992 [root@PEK1000012301 qemu]# git bisect good dfa83a6 Bisecting: a merge base must be tested [e5b3a24181ea0cebf1c5b20f44d016311b7048f0] Update version for v2.3.0 release <<<compile QEMU with this branch and try to launch VM to test as comment#0>>> [root@PEK1000012301 qemu]# git bisect good Bisecting: 1105 revisions left to test after this (roughly 10 steps) [afa25c4bb5bd0732dca4aa0691fd4682d242925f] Merge remote-tracking branch 'remotes/kraxel/tags/pull-sdl-20150611-1' into staging <<<compile QEMU with this branch and try to launch VM to test as comment#0>>> [root@PEK1000012301 qemu]# git bisect good Bisecting: 552 revisions left to test after this (roughly 9 steps) [922f893e57da24bc80db3e79bea56485d1c111fa] ahci: assert is_ncq for process_ncq <<<compile QEMU with this branch and try to launch VM to test as comment#0>>> [root@PEK1000012301 qemu]# git bisect good Bisecting: 274 revisions left to test after this (roughly 8 steps) [711dc6f36b74fe65a6e5a1847f1152717d887f8a] Merge remote-tracking branch 'remotes/cody/tags/jtc-for-upstream-pull-request' into staging <<<compile QEMU with this branch and try to launch VM to test as comment#0>>> [root@PEK1000012301 qemu]# git bisect good Bisecting: 138 revisions left to test after this (roughly 7 steps) [226d007dbd75ec8d0f12d0f9e1ce66caf55d49e4] gdbstub: Set current CPU on interruptions <<<compile QEMU with this branch and try to launch VM to test as comment#0>>> [root@PEK1000012301 qemu]# git bisect bad Bisecting: 67 revisions left to test after this (roughly 6 steps) [b9c46307996856d03ddc1527468ff5401ac03a79] Merge remote-tracking branch 'remotes/mdroth/tags/qga-pull-2015-07-21-tag' into staging <<<compile QEMU with this branch and try to launch VM to test as comment#0>>> [root@PEK1000012301 qemu]# git bisect good Bisecting: 32 revisions left to test after this (roughly 5 steps) [f793d97e454a56d17e404004867985622ca1a63b] Merge remote-tracking branch 'remotes/bonzini/tags/for-upstream' into staging <<<compile QEMU with this branch and try to launch VM to test as comment#0>>> [root@PEK1000012301 qemu]# git bisect bad Bisecting: 17 revisions left to test after this (roughly 4 steps) [80adb8fcad4778376a11d394a9e01516819e2327] tcg/aarch64: use 32-bit offset for 32-bit softmmu emulation <<<compile QEMU with this branch and try to launch VM to test as comment#0>>> [root@PEK1000012301 qemu]# git bisect bad Bisecting: 8 revisions left to test after this (roughly 3 steps) [dc94bd9166af5236a56bd5bb06845911915a925c] Merge remote-tracking branch 'remotes/stefanha/tags/block-pull-request' into staging <<<compile QEMU with this branch and try to launch VM to test as comment#0>>> [root@PEK1000012301 qemu]# git bisect bad Bisecting: 3 revisions left to test after this (roughly 2 steps) [6493c975af75be5b8d9ade954239bdf5492b7911] aio-win32: reorganize polling loop <<<compile QEMU with this branch and try to launch VM to test as comment#0>>> [root@PEK1000012301 qemu]# git bisect good Bisecting: 1 revision left to test after this (roughly 1 step) [21a03d17f2edb1e63f7137d97ba355cc6f19d79f] AioContext: fix broken placement of event_notifier_test_and_clear <<<compile QEMU with this branch and try to launch VM to test as comment#0>>> [root@PEK1000012301 qemu]# git bisect good Bisecting: 0 revisions left to test after this (roughly 0 steps) [05e514b1d4d5bd4209e2c8bbc76ff05c85a235f3] AioContext: optimize clearing the EventNotifier <<<compile QEMU with this branch and try to launch VM to test as comment#0>>> [root@PEK1000012301 qemu]# git bisect bad 05e514b1d4d5bd4209e2c8bbc76ff05c85a235f3 is the first bad commit commit 05e514b1d4d5bd4209e2c8bbc76ff05c85a235f3 Author: Paolo Bonzini <pbonz...@redhat.com> Date: Tue Jul 21 16:07:53 2015 +0200 AioContext: optimize clearing the EventNotifier It is pretty rare for aio_notify to actually set the EventNotifier. It can happen with worker threads such as thread-pool.c's, but otherwise it should never be set thanks to the ctx->notify_me optimization. The previous patch, unfortunately, added an unconditional call to event_notifier_test_and_clear; now add a userspace fast path that avoids the call. Note that it is not possible to do the same with event_notifier_set; it would break, as proved (again) by the included formal model. This patch survived over 3000 reboots on aarch64 KVM. Signed-off-by: Paolo Bonzini <pbonz...@redhat.com> Reviewed-by: Fam Zheng <f...@redhat.com> Tested-by: Richard W.M. Jones <rjo...@redhat.com> Message-id: 1437487673-23740-7-git-send-email-pbonz...@redhat.com Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com> :100644 100644 5c8b266c72b79e07f881a563da189e0267937766 d4770336c5d5355758c3da207b8be5160f66fc5f M aio-posix.c :100644 100644 7afc9992d682d335b4fce58182b580f7f678f503 50a68674589aa3c6418604bfb9320e915f624796 M aio-win32.c :100644 100644 d625e8a8035656711f156078bbc7784b4f4754b0 9a98a74acb99bbf74c004ab2de0d09ca78eac84c M async.c :040000 040000 6f98147da6fdc258f6b7b967ee90d02686311951 11705f58169772ff280c44f4f7d7e7c367600f1a M docs :040000 040000 97f8f766a2ad81d2a262f0379643c3ebaa9d32bc 49b13585c2fad748b6f7c7cb49944dc6c2a149f8 M include Best Regards & Thx, Sibiao Luo -- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1481272 Title: main-loop: WARNING: I/O thread spun for 1000 iterations Status in QEMU: New Bug description: I compile the latest qemu to launch a VM but the monitor output the "main-loop: WARNING: I/O thread spun for 1000 iterations". # /usr/local/bin/qemu-system-x86_64 -name rhel6 -S -no-kvm -m 1024M -realtime mlock=off -smp 1,sockets=1,cores=1,threads=1 -uuid c9dd2a5c-40f2-fd3d-3c54-9cd84f8b9174 -rtc base=utc -drive file=/home/samba-share/ubuntu.img,if=none,id=drive-virtio-disk0,format=qcow2,cache=none -device virtio-blk-pci,bus=pci.0,addr=0x4,drive=drive-virtio-disk0,id=disk,serial=425618d4-871f-4021-bc5d-bcd7f1b5ca9c,bootindex=0 -vnc :1 -boot menu=on -monitor stdio QEMU 2.3.93 monitor - type 'help' for more information (qemu) c (qemu) main-loop: WARNING: I/O thread spun for 1000 iterations <----------------------- qemu]# git branch -v * master e95edef Merge remote-tracking branch 'remotes/sstabellini/tags/xen-migration-2.4-tag' into staging To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1481272/+subscriptions