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[PATCH v6 6/8] blockdev: Acquire AioContext on dirty bitmap functions
From: |
Sergio Lopez |
Subject: |
[PATCH v6 6/8] blockdev: Acquire AioContext on dirty bitmap functions |
Date: |
Wed, 8 Jan 2020 15:31:36 +0100 |
Dirty map addition and removal functions are not acquiring to BDS
AioContext, while they may call to code that expects it to be
acquired.
This may trigger a crash with a stack trace like this one:
#0 0x00007f0ef146370f in __GI_raise (sig=sig@entry=6)
at ../sysdeps/unix/sysv/linux/raise.c:50
#1 0x00007f0ef144db25 in __GI_abort () at abort.c:79
#2 0x0000565022294dce in error_exit
(err=<optimized out>, msg=msg@entry=0x56502243a730 <__func__.16350>
"qemu_mutex_unlock_impl") at util/qemu-thread-posix.c:36
#3 0x00005650222950ba in qemu_mutex_unlock_impl
(mutex=mutex@entry=0x5650244b0240, file=file@entry=0x565022439adf
"util/async.c", line=line@entry=526) at util/qemu-thread-posix.c:108
#4 0x0000565022290029 in aio_context_release
(ctx=ctx@entry=0x5650244b01e0) at util/async.c:526
#5 0x000056502221cd08 in bdrv_can_store_new_dirty_bitmap
(bs=bs@entry=0x5650244dc820, name=name@entry=0x56502481d360 "bitmap1",
granularity=granularity@entry=65536, errp=errp@entry=0x7fff22831718)
at block/dirty-bitmap.c:542
#6 0x000056502206ae53 in qmp_block_dirty_bitmap_add
(errp=0x7fff22831718, disabled=false, has_disabled=<optimized out>,
persistent=<optimized out>, has_persistent=true, granularity=65536,
has_granularity=<optimized out>, name=0x56502481d360 "bitmap1", node=<optimized
out>) at blockdev.c:2894
#7 0x000056502206ae53 in qmp_block_dirty_bitmap_add
(node=<optimized out>, name=0x56502481d360 "bitmap1",
has_granularity=<optimized out>, granularity=<optimized out>,
has_persistent=true, persistent=<optimized out>, has_disabled=false,
disabled=false, errp=0x7fff22831718) at blockdev.c:2856
#8 0x00005650221847a3 in qmp_marshal_block_dirty_bitmap_add
(args=<optimized out>, ret=<optimized out>, errp=0x7fff22831798)
at qapi/qapi-commands-block-core.c:651
#9 0x0000565022247e6c in do_qmp_dispatch
(errp=0x7fff22831790, allow_oob=<optimized out>, request=<optimized out>,
cmds=0x565022b32d60 <qmp_commands>) at qapi/qmp-dispatch.c:132
#10 0x0000565022247e6c in qmp_dispatch
(cmds=0x565022b32d60 <qmp_commands>, request=<optimized out>,
allow_oob=<optimized out>) at qapi/qmp-dispatch.c:175
#11 0x0000565022166061 in monitor_qmp_dispatch
(mon=0x56502450faa0, req=<optimized out>) at monitor/qmp.c:145
#12 0x00005650221666fa in monitor_qmp_bh_dispatcher
(data=<optimized out>) at monitor/qmp.c:234
#13 0x000056502228f866 in aio_bh_call (bh=0x56502440eae0)
at util/async.c:117
#14 0x000056502228f866 in aio_bh_poll (ctx=ctx@entry=0x56502440d7a0)
at util/async.c:117
#15 0x0000565022292c54 in aio_dispatch (ctx=0x56502440d7a0)
at util/aio-posix.c:459
#16 0x000056502228f742 in aio_ctx_dispatch
(source=<optimized out>, callback=<optimized out>, user_data=<optimized
out>) at util/async.c:260
#17 0x00007f0ef5ce667d in g_main_dispatch (context=0x56502449aa40)
at gmain.c:3176
#18 0x00007f0ef5ce667d in g_main_context_dispatch
(context=context@entry=0x56502449aa40) at gmain.c:3829
#19 0x0000565022291d08 in glib_pollfds_poll () at util/main-loop.c:219
#20 0x0000565022291d08 in os_host_main_loop_wait
(timeout=<optimized out>) at util/main-loop.c:242
#21 0x0000565022291d08 in main_loop_wait (nonblocking=<optimized out>)
at util/main-loop.c:518
#22 0x00005650220743c1 in main_loop () at vl.c:1828
#23 0x0000565021f20a72 in main
(argc=<optimized out>, argv=<optimized out>, envp=<optimized out>)
at vl.c:4504
Fix this by acquiring the AioContext at qmp_block_dirty_bitmap_add()
and qmp_block_dirty_bitmap_add().
RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=1782175
Signed-off-by: Sergio Lopez <address@hidden>
---
blockdev.c | 20 +++++++++++++++++---
1 file changed, 17 insertions(+), 3 deletions(-)
diff --git a/blockdev.c b/blockdev.c
index 1dacbc20ec..292961a88d 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -2984,6 +2984,7 @@ void qmp_block_dirty_bitmap_add(const char *node, const
char *name,
{
BlockDriverState *bs;
BdrvDirtyBitmap *bitmap;
+ AioContext *aio_context;
if (!name || name[0] == '\0') {
error_setg(errp, "Bitmap name cannot be empty");
@@ -2995,11 +2996,14 @@ void qmp_block_dirty_bitmap_add(const char *node, const
char *name,
return;
}
+ aio_context = bdrv_get_aio_context(bs);
+ aio_context_acquire(aio_context);
+
if (has_granularity) {
if (granularity < 512 || !is_power_of_2(granularity)) {
error_setg(errp, "Granularity must be power of 2 "
"and at least 512");
- return;
+ goto out;
}
} else {
/* Default to cluster size, if available: */
@@ -3017,12 +3021,12 @@ void qmp_block_dirty_bitmap_add(const char *node, const
char *name,
if (persistent &&
!bdrv_can_store_new_dirty_bitmap(bs, name, granularity, errp))
{
- return;
+ goto out;
}
bitmap = bdrv_create_dirty_bitmap(bs, granularity, name, errp);
if (bitmap == NULL) {
- return;
+ goto out;
}
if (disabled) {
@@ -3030,6 +3034,9 @@ void qmp_block_dirty_bitmap_add(const char *node, const
char *name,
}
bdrv_dirty_bitmap_set_persistence(bitmap, persistent);
+
+out:
+ aio_context_release(aio_context);
}
static BdrvDirtyBitmap *do_block_dirty_bitmap_remove(
@@ -3038,20 +3045,26 @@ static BdrvDirtyBitmap *do_block_dirty_bitmap_remove(
{
BlockDriverState *bs;
BdrvDirtyBitmap *bitmap;
+ AioContext *aio_context;
bitmap = block_dirty_bitmap_lookup(node, name, &bs, errp);
if (!bitmap || !bs) {
return NULL;
}
+ aio_context = bdrv_get_aio_context(bs);
+ aio_context_acquire(aio_context);
+
if (bdrv_dirty_bitmap_check(bitmap, BDRV_BITMAP_BUSY | BDRV_BITMAP_RO,
errp)) {
+ aio_context_release(aio_context);
return NULL;
}
if (bdrv_dirty_bitmap_get_persistence(bitmap) &&
bdrv_remove_persistent_dirty_bitmap(bs, name, errp) < 0)
{
+ aio_context_release(aio_context);
return NULL;
}
@@ -3063,6 +3076,7 @@ static BdrvDirtyBitmap *do_block_dirty_bitmap_remove(
*bitmap_bs = bs;
}
+ aio_context_release(aio_context);
return release ? NULL : bitmap;
}
--
2.23.0
- [PATCH v6 0/8] blockdev: Fix AioContext handling for various blockdev actions, Sergio Lopez, 2020/01/08
- [PATCH v6 1/8] blockdev: fix coding style issues in drive_backup_prepare, Sergio Lopez, 2020/01/08
- [PATCH v6 2/8] blockdev: unify qmp_drive_backup and drive-backup transaction paths, Sergio Lopez, 2020/01/08
- [PATCH v6 3/8] blockdev: unify qmp_blockdev_backup and blockdev-backup transaction paths, Sergio Lopez, 2020/01/08
- [PATCH v6 4/8] blockdev: honor bdrv_try_set_aio_context() context requirements, Sergio Lopez, 2020/01/08
- [PATCH v6 5/8] block/backup-top: Don't acquire context while dropping top, Sergio Lopez, 2020/01/08
- [PATCH v6 6/8] blockdev: Acquire AioContext on dirty bitmap functions,
Sergio Lopez <=
- [PATCH v6 7/8] blockdev: Return bs to the proper context on snapshot abort, Sergio Lopez, 2020/01/08
- [PATCH v6 8/8] iotests: Test handling of AioContexts with some blockdev actions, Sergio Lopez, 2020/01/08
- Re: [PATCH v6 0/8] blockdev: Fix AioContext handling for various blockdev actions, Kevin Wolf, 2020/01/15
- Re: [PATCH v6 0/8] blockdev: Fix AioContext handling for various blockdev actions, Paolo Bonzini, 2020/01/16