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[Qemu-devel] [PATCH for 2.9 1/1] block: add missed aio_context_acquire i
From: |
Denis V. Lunev |
Subject: |
[Qemu-devel] [PATCH for 2.9 1/1] block: add missed aio_context_acquire into release_drive |
Date: |
Tue, 28 Mar 2017 19:12:46 +0300 |
Recently we expirience hang with iothreads enabled with the following
call trace:
Thread 1 (Thread 0x7fa95efebc80 (LWP 177117)):
0 ppoll () from /lib64/libc.so.6
2 qemu_poll_ns () at qemu-timer.c:313
3 aio_poll () at aio-posix.c:457
4 bdrv_flush () at block/io.c:2641
5 bdrv_close () at block.c:2143
6 bdrv_delete () at block.c:2352
7 bdrv_unref () at block.c:3429
8 blk_remove_bs () at block/block-backend.c:427
9 blk_delete () at block/block-backend.c:178
10 blk_unref () at block/block-backend.c:226
11 object_property_del_all () at qom/object.c:399
12 object_finalize () at qom/object.c:461
13 object_unref () at qom/object.c:898
14 object_property_del_child () at qom/object.c:422
15 qmp_marshal_device_del () at qmp-marshal.c:1145
16 handle_qmp_command () at /usr/src/debug/qemu-2.6.0/monitor.c:3929
Technically bdrv_flush() stucks in
while (rwco.ret == NOT_DONE) {
aio_poll(aio_context, true);
}
but rwco.ret is equal to 0 thus we have missed wakeup. Code investigation
reveals that we do not have performed aio_context_acquire() on this call
stack.
This patch adds missed lock.
Signed-off-by: Denis V. Lunev <address@hidden>
CC: Kevin Wolf <address@hidden>
CC: Max Reitz <address@hidden>
CC: Eric Blake <address@hidden>
CC: Markus Armbruster <address@hidden>
---
hw/core/qdev-properties-system.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/hw/core/qdev-properties-system.c b/hw/core/qdev-properties-system.c
index c34be1c..e885e65 100644
--- a/hw/core/qdev-properties-system.c
+++ b/hw/core/qdev-properties-system.c
@@ -124,8 +124,12 @@ static void release_drive(Object *obj, const char *name,
void *opaque)
BlockBackend **ptr = qdev_get_prop_ptr(dev, prop);
if (*ptr) {
+ AioContext *ctx = blk_get_aio_context(*ptr);
+
+ aio_context_acquire(ctx);
blockdev_auto_del(*ptr);
blk_detach_dev(*ptr, dev);
+ aio_context_release(ctx);
}
}
--
2.7.4
- [Qemu-devel] [PATCH for 2.9 1/1] block: add missed aio_context_acquire into release_drive,
Denis V. Lunev <=