From: Xujun Ma <1839428@bugs.launchpad.net>
To: qemu-devel@nongnu.org
Subject: [Qemu-devel] [Bug 1839428] Re: qemu core dumped when repeat "system_reset" multiple times during guest boot
Date: Tue, 27 Aug 2019 06:16:52 -0000 [thread overview]
Message-ID: <156688661263.3027.3336339084032447737.malone@chaenomeles.canonical.com> (raw)
In-Reply-To: 156524772160.13996.4537778553837159229.malonedeb@wampee.canonical.com
I found the commit that introduced this regression.
commit 57830a499f7c815bb0cb325c94a3d8c910d13cfa (HEAD)
Author: Denis Plotnikov <dplotnikov@virtuozzo.com>
Date: Fri Feb 15 16:03:25 2019 +0300
block: don't set the same context
Adds a fast path on aio context setting preventing
unnecessary context setting routine.
Also, it prevents issues with cyclic walk of child
bds-es appeared because of registering aio walking
notifiers:
Call stack:
0 __GI_raise
1 __GI_abort
2 __assert_fail_base
3 __GI___assert_fail
4 bdrv_detach_aio_context (bs=0x55f54d65c000) <<<
5 bdrv_detach_aio_context (bs=0x55f54fc8a800)
6 bdrv_set_aio_context (bs=0x55f54fc8a800, ...)
7 block_job_attached_aio_context
8 bdrv_attach_aio_context (bs=0x55f54d65c000, ...) <<<
9 bdrv_set_aio_context (bs=0x55f54d65c000)
10 blk_set_aio_context
11 virtio_blk_data_plane_stop
12 virtio_bus_stop_ioeventfd
13 virtio_vmstate_change
14 vm_state_notify (running=0, state=RUN_STATE_SHUTDOWN)
15 do_vm_stop (state=RUN_STATE_SHUTDOWN, send_stop=true)
16 vm_stop (state=RUN_STATE_SHUTDOWN)
17 main_loop_should_exit
18 main_loop
19 main
This can happen because of "new" context attachment to VM disk bds.
When attaching a new context the corresponding aio context handler is
called for each of aio_notifiers registered on the VM disk bds context.
Among those handlers, there is the block_job_attached_aio_context handler
which sets a new aio context for the block job bds. When doing so,
the old context is detached from all the block job bds children and one of
them is the VM disk bds, serving as backing store for the blockjob bds,
although the VM disk bds is actually the initializer of that process.
Since the VM disk bds is protected with walking_aio_notifiers flag
from double processing in recursive calls, the assert fires.
Signed-off-by: Denis Plotnikov <dplotnikov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block.c b/block.c
index 4ad0e90d7e..0c12632661 100644
--- a/block.c
+++ b/block.c
@@ -5265,6 +5265,10 @@ void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context)
{
AioContext *ctx = bdrv_get_aio_context(bs);
+ if (ctx == new_context) {
+ return;
+ }
+
aio_disable_external(ctx);
bdrv_parent_drained_begin(bs, NULL, false);
bdrv_drain(bs); /* ensure there are no in-flight requests */
--
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https://bugs.launchpad.net/bugs/1839428
Title:
qemu core dumped when repeat "system_reset" multiple times during
guest boot
Status in QEMU:
Confirmed
Bug description:
commit 864ab314f1d924129d06ac7b571f105a2b76a4b2 (HEAD, tag: v4.1.0-rc4, origin/master, origin/HEAD, master)
Test arch:x86 and power
Steps:
1.Boot up guest with command
power cmdline:
/usr/libexec/backup/qemu-kvm \
-smp 8 \
-m 4096 \
-nodefaults \
-device virtio-blk-pci,id=image1,drive=drive_image1,bootindex=1,bus=pci.0,addr=0x7 \
-drive file=rhel77-ppc64le-virtio.qcow2,if=none,id=drive_image1,format=qcow2,cache=none \
-chardev stdio,mux=on,id=serial_id_serial0,server,nowait,signal=off \
-device spapr-vty,id=serial111,chardev=serial_id_serial0 \
-mon chardev=serial_id_serial0,mode=readline \
x86 cmdline:
/usr/libexec/qemu-kvm \
-m 4096 -smp 8 \
-boot menu=on \
-device virtio-blk-pci,id=image1,drive=drive_image1\
-drive file=rhel77-64-virtio.qcow2,if=none,id=drive_image1,format=qcow2,cache=none \
-vga std \
-vnc :9 \
-nographic \
-device virtio-net-pci,netdev=net0,id=nic0,mac=52:54:00:c4:e7:84 \
-netdev tap,id=net0,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown,vhost=on \
2.when guest start to boot up kernel(when no output infomation),run
hmp command "system_reset"
Result:
Sometimes,qemu core dumped with error as following:
system_reset
(qemu) qemu-system-ppc64: /root/qemu/hw/virtio/virtio.c:225: vring_get_region_caches: Assertion `caches != NULL' failed.
b.sh: line 11: 73679 Aborted (core dumped) /usr/local/bin/qemu-system-ppc64 -enable-kvm -smp 8 -m 4096 -nodefaults -device virtio-blk-pci,id=image1,drive=drive_image1,bootindex=1,bus=pci.0,addr=0x7 -drive file=rhel77-ppc64le-virtio.qcow2,if=none,id=drive_image1,format=qcow2,cache=none -chardev stdio,mux=on,id=serial_id_serial0,server,nowait,signal=off -device spapr-vty,id=serial111,chardev=serial_id_serial0 -mon chardev=serial_id_serial0,mode=readline
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next prev parent reply other threads:[~2019-08-27 6:26 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-08 7:02 [Qemu-devel] [Bug 1839428] [NEW] qemu core dumped when repeat "system_reset" multiple times during guest boot Xujun Ma
2019-08-08 7:26 ` [Qemu-devel] [Bug 1839428] " Xujun Ma
2019-08-15 20:34 ` Philippe Mathieu-Daudé
2019-08-16 9:06 ` Philippe Mathieu-Daudé
2019-08-27 6:16 ` Xujun Ma [this message]
2019-09-18 13:17 ` Stefan Hajnoczi
2020-01-09 13:40 ` Thomas Huth
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