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[Bug 1805256] Re: qemu-img hangs on rcu_call_ready_event logic in Aarch6
From: |
Fred Kimmy |
Subject: |
[Bug 1805256] Re: qemu-img hangs on rcu_call_ready_event logic in Aarch64 when converting images |
Date: |
Tue, 17 Dec 2019 01:34:00 -0000 |
include/block/aio.h | 3 +++
qemu-img.c | 4 ++++
util/async.c | 5 +----
3 files changed, 8 insertions(+), 4 deletions(-)
diff --git a/include/block/aio.h b/include/block/aio.h
index e9bc04c..9153d87 100644
--- a/include/block/aio.h
+++ b/include/block/aio.h
@@ -89,6 +89,9 @@ struct AioContext {
*/
uint32_t notify_me;
+ /* force to notify for qemu-img convert */
+ bool notify_for_convert;
+
/* lock to protect between bh's adders and deleter */
QemuMutex bh_lock;
diff --git a/qemu-img.c b/qemu-img.c
index 60a2be3..cf037aa 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -2411,6 +2411,10 @@ static int img_convert(int argc, char **argv)
.wr_in_order = wr_in_order,
.num_coroutines = num_coroutines,
};
+
+ AioContext *ctx = qemu_get_aio_context();
+ ctx->notify_for_convert = 1;
+
ret = convert_do_copy(&state);
out:
diff --git a/util/async.c b/util/async.c
index 042bf8a..af235fc 100644
--- a/util/async.c
+++ b/util/async.c
@@ -336,12 +336,9 @@ void aio_notify(AioContext *ctx)
* with atomic_or in aio_ctx_prepare or atomic_add in aio_poll.
*/
smp_mb();
- if (ctx->notify_me) {
+ if (ctx->notify_me || ctx->notify_for_convert) {
event_notifier_set(&ctx->notifier);
atomic_mb_set(&ctx->notified, true);
-#if defined(__aarch64__)
- kill(getpid(), SIGIO);
-#endif
}
}
Can you try this aboving patchset to slove it?
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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:
Confirmed
Status in QEMU:
In Progress
Status in qemu package in Ubuntu:
Confirmed
Status in qemu source package in Bionic:
Confirmed
Status in qemu source package in Disco:
Confirmed
Status in qemu source package in Eoan:
In Progress
Status in qemu source package in Focal:
Confirmed
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 0x0000ffffbf1ad81c in __GI_ppoll
#1 0x0000aaaaaabcf73c in ppoll
#2 qemu_poll_ns
#3 0x0000aaaaaabd0764 in os_host_main_loop_wait
#4 main_loop_wait
...
(gdb) thread 2
...
(gdb) bt
#0 syscall ()
#1 0x0000aaaaaabd41cc in qemu_futex_wait
#2 qemu_event_wait (ev=ev@entry=0xaaaaaac86ce8 <rcu_call_ready_event>)
#3 0x0000aaaaaabed05c in call_rcu_thread
#4 0x0000aaaaaabd34c8 in qemu_thread_start
#5 0x0000ffffbf25c880 in start_thread
#6 0x0000ffffbf1b6b9c in thread_start ()
(gdb) thread 3
...
(gdb) bt
#0 0x0000ffffbf11aa20 in __GI___sigtimedwait
#1 0x0000ffffbf2671b4 in __sigwait
#2 0x0000aaaaaabd1ddc in sigwait_compat
#3 0x0000aaaaaabd34c8 in qemu_thread_start
#4 0x0000ffffbf25c880 in start_thread
#5 0x0000ffffbf1b6b9c in thread_start
----
(gdb) run
Starting program: /usr/bin/qemu-img convert -f qcow2 -O qcow2
./disk01.ext4.qcow2 ./output.qcow2
[New Thread 0xffffbec5ad90 (LWP 72839)]
[New Thread 0xffffbe459d90 (LWP 72840)]
[New Thread 0xffffbdb57d90 (LWP 72841)]
[New Thread 0xffffacac9d90 (LWP 72859)]
[New Thread 0xffffa7ffed90 (LWP 72860)]
[New Thread 0xffffa77fdd90 (LWP 72861)]
[New Thread 0xffffa6ffcd90 (LWP 72862)]
[New Thread 0xffffa67fbd90 (LWP 72863)]
[New Thread 0xffffa5ffad90 (LWP 72864)]
[Thread 0xffffa5ffad90 (LWP 72864) exited]
[Thread 0xffffa6ffcd90 (LWP 72862) exited]
[Thread 0xffffa77fdd90 (LWP 72861) exited]
[Thread 0xffffbdb57d90 (LWP 72841) exited]
[Thread 0xffffa67fbd90 (LWP 72863) exited]
[Thread 0xffffacac9d90 (LWP 72859) exited]
[Thread 0xffffa7ffed90 (LWP 72860) exited]
<HUNG w/ 3 threads in the stack trace showed before>
"""
All the tasks left are blocked in a system call, so no task left to call
qemu_futex_wake() to unblock thread #2 (in futex()), which would unblock
thread #1 (doing poll() in a pipe with thread #2).
Those 7 threads exit before disk conversion is complete (sometimes in
the beginning, sometimes at the end).
----
[ Original Description ]
On the HiSilicon D06 system - a 96 core NUMA arm64 box - qemu-img
frequently hangs (~50% of the time) with this command:
qemu-img convert -f qcow2 -O qcow2 /tmp/cloudimg /tmp/cloudimg2
Where "cloudimg" is a standard qcow2 Ubuntu cloud image. This
qcow2->qcow2 conversion happens to be something uvtool does every time
it fetches images.
Once hung, attaching gdb gives the following backtrace:
(gdb) bt
#0 0x0000ffffae4f8154 in __GI_ppoll (fds=0xaaaae8a67dc0,
nfds=187650274213760,
timeout=<optimized out>, timeout@entry=0x0, sigmask=0xffffc123b950)
at ../sysdeps/unix/sysv/linux/ppoll.c:39
#1 0x0000aaaabbefaf00 in ppoll (__ss=0x0, __timeout=0x0, __nfds=<optimized
out>,
__fds=<optimized out>) at /usr/include/aarch64-linux-gnu/bits/poll2.h:77
#2 qemu_poll_ns (fds=<optimized out>, nfds=<optimized out>,
timeout=timeout@entry=-1) at util/qemu-timer.c:322
#3 0x0000aaaabbefbf80 in os_host_main_loop_wait (timeout=-1)
at util/main-loop.c:233
#4 main_loop_wait (nonblocking=<optimized out>) at util/main-loop.c:497
#5 0x0000aaaabbe2aa30 in convert_do_copy (s=0xffffc123bb58) at
qemu-img.c:1980
#6 img_convert (argc=<optimized out>, argv=<optimized out>) at
qemu-img.c:2456
#7 0x0000aaaabbe2333c in main (argc=7, argv=<optimized out>) at
qemu-img.c:4975
Reproduced w/ latest QEMU git (@ 53744e0a182)
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- [Bug 1805256] Re: qemu-img hangs on rcu_call_ready_event logic in Aarch64 when converting images, dann frazier, 2019/12/13
- [Bug 1805256] Re: qemu-img hangs on rcu_call_ready_event logic in Aarch64 when converting images,
Fred Kimmy <=
- [Bug 1805256] Re: qemu-img hangs on rcu_call_ready_event logic in Aarch64 when converting images, dann frazier, 2019/12/17
- [Bug 1805256] Re: qemu-img hangs on rcu_call_ready_event logic in Aarch64 when converting images, Rafael David Tinoco, 2019/12/17
- [Bug 1805256] Re: qemu-img hangs on rcu_call_ready_event logic in Aarch64 when converting images, iveskim, 2019/12/18
- [Bug 1805256] Re: qemu-img hangs on rcu_call_ready_event logic in Aarch64 when converting images, dann frazier, 2019/12/18
- [Bug 1805256] Re: qemu-img hangs on rcu_call_ready_event logic in Aarch64 when converting images, Ubuntu Foundations Team Bug Bot, 2019/12/18