On 09/18/12 12:31, Kevin Wolf wrote:
Am 18.09.2012 12:28, schrieb Peter Lieven:
On 09/17/12 22:12, Peter Lieven wrote:
On 09/17/12 10:41, Kevin Wolf wrote:
Am 16.09.2012 12:13, schrieb Peter Lieven:
Hi,
when trying to block migrate a VM from one node to another, the source
VM crashed with the following assertion:
block.c:3829: bdrv_set_in_use: Assertion `bs->in_use != in_use' failed.
Is this sth already addresses/known?
Not that I'm aware of, at least.
Block migration doesn't seem to check whether the device is already in
use, maybe this is the problem. Not sure why it would be in use, though,
and in my quick test it didn't crash.
So we need some more information: What's you command line, did you do
anything specific in the monitor with block devices, what does the
stacktrace look like, etc.?
kevin, it seems that i can very easily force a crash if I cancel a
running block migration.
if I understand correctly what happens there are aio callbacks coming in
after
blk_mig_cleanup() has been called.
what is the proper way to detect this in blk_mig_read_cb()?
You could try this, it doesn't detect the situation in
blk_mig_read_cb(), but ensures that all callbacks happen before we do
the actual cleanup (completely untested):
after testing it for half an hour i can say, it seems to fix the problem.
no segfaults and also no other assertions.
while searching I have seen that the queses blk_list and bmds_list are
initialized at
qemu startup. wouldn't it be better to initialize them at init_blk_migration
or at least check that they are really empty? i have also seen that
prev_time_offset
is not initialized.
thank you,
peter
sth like this:
--- qemu-kvm-1.2.0/block-migration.c.orig 2012-09-17
21:14:44.458429855 +0200
+++ qemu-kvm-1.2.0/block-migration.c 2012-09-17 21:15:40.599736962 +0200
@@ -311,8 +311,12 @@ static void init_blk_migration(QEMUFile
block_mig_state.prev_progress = -1;
block_mig_state.bulk_completed = 0;
block_mig_state.total_time = 0;
+ block_mig_state.prev_time_offset = 0;
block_mig_state.reads = 0;
+ QSIMPLEQ_INIT(&block_mig_state.bmds_list);
+ QSIMPLEQ_INIT(&block_mig_state.blk_list);
+
bdrv_iterate(init_blk_migration_it, NULL);
}
@@ -760,9 +764,6 @@ SaveVMHandlers savevm_block_handlers = {
void blk_mig_init(void)
{
- QSIMPLEQ_INIT(&block_mig_state.bmds_list);
- QSIMPLEQ_INIT(&block_mig_state.blk_list);
-
register_savevm_live(NULL, "block", 0, 1, &savevm_block_handlers,
&block_mig_state);
}
diff --git a/block-migration.c b/block-migration.c
index 7def8ab..ed93301 100644
--- a/block-migration.c
+++ b/block-migration.c
@@ -519,6 +519,8 @@ static void blk_mig_cleanup(void)
BlkMigDevState *bmds;
BlkMigBlock *blk;
+ bdrv_drain_all();
+
set_dirty_tracking(0);
while ((bmds = QSIMPLEQ_FIRST(&block_mig_state.bmds_list)) != NULL) {
--
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