Re: [Bug 1805256] Re: [Qemu-devel] qemu_futex_wait() lockups in ARM64: 2 possible issues
Patchew URL: https://patchew.org/QEMU/20191011175536.GB25464@xps13.dannf/ Hi, This series seems to have some coding style problems. See output below for more information: Subject: [Bug 1805256] Re: [Qemu-devel] qemu_futex_wait() lockups in ARM64: 2 possible issues Type: series Message-id: 20191011175536.GB25464@xps13.dannf === TEST SCRIPT BEGIN === #!/bin/bash git rev-parse base > /dev/null || exit 0 git config --local diff.renamelimit 0 git config --local diff.renames True git config --local diff.algorithm histogram ./scripts/checkpatch.pl --mailback base.. === TEST SCRIPT END === Switched to a new branch 'test' d3707c3 qemu_futex_wait() lockups in ARM64: 2 possible issues === OUTPUT BEGIN === WARNING: Block comments use a leading /* on a separate line #66: FILE: util/async.c:345: +/* Using atomic_mb_read ensures that e.g. bh->scheduled is written before ERROR: code indent should never use tabs #74: FILE: util/async.c:350: +^Ievent_notifier_set(>notifier);$ ERROR: Missing Signed-off-by: line(s) total: 2 errors, 1 warnings, 33 lines checked Commit d3707c31b5da (qemu_futex_wait() lockups in ARM64: 2 possible issues) has style problems, please review. If any of these errors are false positives report them to the maintainer, see CHECKPATCH in MAINTAINERS. === OUTPUT END === Test command exited with code: 1 The full log is available at http://patchew.org/logs/20191011175536.GB25464@xps13.dannf/testing.checkpatch/?type=message. --- Email generated automatically by Patchew [https://patchew.org/]. Please send your feedback to patchew-de...@redhat.com
Re: [Bug 1805256] Re: [Qemu-devel] qemu_futex_wait() lockups in ARM64: 2 possible issues
Patchew URL: https://patchew.org/QEMU/20191011175536.GB25464@xps13.dannf/
Hi,
This series failed the docker-mingw@fedora build test. Please find the testing
commands and
their output below. If you have Docker installed, you can probably reproduce it
locally.
=== TEST SCRIPT BEGIN ===
#! /bin/bash
export ARCH=x86_64
make docker-image-fedora V=1 NETWORK=1
time make docker-test-mingw@fedora J=14 NETWORK=1
=== TEST SCRIPT END ===
In file included from /tmp/qemu-test/src/include/qemu/osdep.h:51,
from /tmp/qemu-test/src/util/async.c:26:
/tmp/qemu-test/src/util/async.c: In function 'aio_notify':
/tmp/qemu-test/src/include/qemu/compiler.h:86:36: error: static assertion
failed: "not expecting: sizeof(*>notify_me) > ATOMIC_REG_SIZE"
#define QEMU_BUILD_BUG_MSG(x, msg) _Static_assert(!(x), msg)
^~
/tmp/qemu-test/src/include/qemu/compiler.h:94:30: note: in expansion of macro
'QEMU_BUILD_BUG_MSG'
---
/tmp/qemu-test/src/util/async.c:349:9: note: in expansion of macro
'atomic_mb_read'
if (atomic_mb_read(>notify_me)) {
^~
make: *** [/tmp/qemu-test/src/rules.mak:69: util/async.o] Error 1
make: *** Waiting for unfinished jobs
Traceback (most recent call last):
File "./tests/docker/docker.py", line 662, in
---
raise CalledProcessError(retcode, cmd)
subprocess.CalledProcessError: Command '['sudo', '-n', 'docker', 'run',
'--label', 'com.qemu.instance.uuid=b90449ea684e4a14ad6b34f4f5dcb0c9', '-u',
'1001', '--security-opt', 'seccomp=unconfined', '--rm', '-e', 'TARGET_LIST=',
'-e', 'EXTRA_CONFIGURE_OPTS=', '-e', 'V=', '-e', 'J=14', '-e', 'DEBUG=', '-e',
'SHOW_ENV=', '-e', 'CCACHE_DIR=/var/tmp/ccache', '-v',
'/home/patchew/.cache/qemu-docker-ccache:/var/tmp/ccache:z', '-v',
'/var/tmp/patchew-tester-tmp-0y2eb54d/src/docker-src.2019-10-11-20.12.57.30254:/var/tmp/qemu:z,ro',
'qemu:fedora', '/var/tmp/qemu/run', 'test-mingw']' returned non-zero exit
status 2.
filter=--filter=label=com.qemu.instance.uuid=b90449ea684e4a14ad6b34f4f5dcb0c9
make[1]: *** [docker-run] Error 1
make[1]: Leaving directory `/var/tmp/patchew-tester-tmp-0y2eb54d/src'
make: *** [docker-run-test-mingw@fedora] Error 2
real11m27.735s
user0m7.532s
The full log is available at
http://patchew.org/logs/20191011175536.GB25464@xps13.dannf/testing.docker-mingw@fedora/?type=message.
---
Email generated automatically by Patchew [https://patchew.org/].
Please send your feedback to patchew-de...@redhat.com
[Bug 1805256] Re: [Qemu-devel] qemu_futex_wait() lockups in ARM64: 2 possible issues
On Fri, Oct 11, 2019 at 08:30:02AM +, Jan Glauber wrote:
> On Fri, Oct 11, 2019 at 10:18:18AM +0200, Paolo Bonzini wrote:
> > On 11/10/19 08:05, Jan Glauber wrote:
> > > On Wed, Oct 09, 2019 at 11:15:04AM +0200, Paolo Bonzini wrote:
> > >>> ...but if I bump notify_me size to uint64_t the issue goes away.
> > >>
> > >> Ouch. :) Is this with or without my patch(es)?
> >
> > You didn't answer this question.
>
> Oh, sorry... I did but the mail probably didn't make it out.
> I have both of your changes applied (as I think they make sense).
>
> > >> Also, what if you just add a dummy uint32_t after notify_me?
> > >
> > > With the dummy the testcase also runs fine for 500 iterations.
> >
> > You might be lucky and causing list_lock to be in another cache line.
> > What if you add __attribute__((aligned(16)) to notify_me (and keep the
> > dummy)?
>
> Good point. I'll try to force both into the same cacheline.
On the Hi1620, this still hangs in the first iteration:
diff --git a/include/block/aio.h b/include/block/aio.h
index 6b0d52f732..00e56a5412 100644
--- a/include/block/aio.h
+++ b/include/block/aio.h
@@ -82,7 +82,7 @@ struct AioContext {
* Instead, the aio_poll calls include both the prepare and the
* dispatch phase, hence a simple counter is enough for them.
*/
-uint32_t notify_me;
+__attribute__((aligned(16))) uint64_t notify_me;
/* A lock to protect between QEMUBH and AioHandler adders and deleter,
* and to ensure that no callbacks are removed while we're walking and
diff --git a/util/async.c b/util/async.c
index ca83e32c7f..024c4c567d 100644
--- a/util/async.c
+++ b/util/async.c
@@ -242,7 +242,7 @@ aio_ctx_check(GSource *source)
aio_notify_accept(ctx);
for (bh = ctx->first_bh; bh; bh = bh->next) {
-if (bh->scheduled) {
+if (atomic_mb_read(>scheduled)) {
return true;
}
}
@@ -342,12 +342,12 @@ LinuxAioState *aio_get_linux_aio(AioContext *ctx)
void aio_notify(AioContext *ctx)
{
-/* Write e.g. bh->scheduled before reading ctx->notify_me. Pairs
- * with atomic_or in aio_ctx_prepare or atomic_add in aio_poll.
+/* Using atomic_mb_read ensures that e.g. bh->scheduled is written before
+ * ctx->notify_me is read. Pairs with atomic_or in aio_ctx_prepare or
+ * atomic_add in aio_poll.
*/
-smp_mb();
-if (ctx->notify_me) {
-event_notifier_set(>notifier);
+if (atomic_mb_read(>notify_me)) {
+ event_notifier_set(>notifier);
atomic_mb_set(>notified, true);
}
}
--
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https://bugs.launchpad.net/bugs/1805256
Title:
qemu-img hangs on rcu_call_ready_event logic in Aarch64 when
converting images
Status in kunpeng920:
New
Status in QEMU:
In Progress
Status in qemu package in Ubuntu:
In Progress
Status in qemu source package in Bionic:
New
Status in qemu source package in Disco:
New
Status in qemu source package in Eoan:
In Progress
Status in qemu source package in FF-Series:
New
Bug description:
Command:
qemu-img convert -f qcow2 -O qcow2 ./disk01.qcow2 ./output.qcow2
Hangs indefinitely approximately 30% of the runs.
Workaround:
qemu-img convert -m 1 -f qcow2 -O qcow2 ./disk01.qcow2 ./output.qcow2
Run "qemu-img convert" with "a single coroutine" to avoid this issue.
(gdb) thread 1
...
(gdb) bt
#0 0xbf1ad81c in __GI_ppoll
#1 0xaabcf73c in ppoll
#2 qemu_poll_ns
#3 0xaabd0764 in os_host_main_loop_wait
#4 main_loop_wait
...
(gdb) thread 2
...
(gdb) bt
#0 syscall ()
#1 0xaabd41cc in qemu_futex_wait
#2 qemu_event_wait (ev=ev@entry=0xaac86ce8 )
#3 0xaabed05c in call_rcu_thread
#4 0xaabd34c8 in qemu_thread_start
#5 0xbf25c880 in start_thread
#6 0xbf1b6b9c in thread_start ()
(gdb) thread 3
...
(gdb) bt
#0 0xbf11aa20 in __GI___sigtimedwait
#1 0xbf2671b4 in __sigwait
#2 0xaabd1ddc in sigwait_compat
#3 0xaabd34c8 in qemu_thread_start
#4 0xbf25c880 in start_thread
#5 0xbf1b6b9c in thread_start
(gdb) run
Starting program: /usr/bin/qemu-img convert -f qcow2 -O qcow2
./disk01.ext4.qcow2 ./output.qcow2
[New Thread 0xbec5ad90 (LWP 72839)]
[New Thread 0xbe459d90 (LWP 72840)]
[New Thread 0xbdb57d90 (LWP 72841)]
[New Thread 0xacac9d90 (LWP 72859)]
[New Thread 0xa7ffed90 (LWP 72860)]
[New Thread 0xa77fdd90 (LWP 72861)]
[New Thread 0xa6ffcd90 (LWP 72862)]
[New Thread 0xa67fbd90 (LWP 72863)]
[New Thread 0xa5ffad90 (LWP 72864)]
[Thread 0xa5ffad90 (LWP 72864) exited]
[Thread 0xa6ffcd90 (LWP 72862) exited]
[Thread 0xa77fdd90 (LWP 72861) exited]
[Thread 0xbdb57d90 (LWP 72841) exited]
[Thread 0xa67fbd90 (LWP 72863) exited]
[Thread 0xacac9d90 (LWP
