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[PATCH 2/5] migration: Shutdown src in await_return_path_close_on_source
From: |
Peter Xu |
Subject: |
[PATCH 2/5] migration: Shutdown src in await_return_path_close_on_source() |
Date: |
Tue, 20 Jul 2021 21:21:31 -0400 |
We have a logic in await_return_path_close_on_source() that we will explicitly
shutdown the socket when migration encounters errors. However it could be racy
because from_dst_file could have been reset right after checking it but before
passing it to qemu_file_shutdown() by the rp_thread.
Fix it by shutdown() on the src file instead. Since they must be a pair of
qemu files, shutdown on either of them will work the same.
Since at it, drop the check for from_dst_file directly, which makes the
behavior even more predictable.
Reported-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
---
migration/migration.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/migration/migration.c b/migration/migration.c
index 21b94f75a3..4f48cde796 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -2882,12 +2882,15 @@ static int
await_return_path_close_on_source(MigrationState *ms)
* rp_thread will exit, however if there's an error we need to cause
* it to exit.
*/
- if (qemu_file_get_error(ms->to_dst_file) && ms->rp_state.from_dst_file) {
+ if (qemu_file_get_error(ms->to_dst_file)) {
/*
* shutdown(2), if we have it, will cause it to unblock if it's stuck
- * waiting for the destination.
+ * waiting for the destination. We do shutdown on to_dst_file should
+ * also shutdown the from_dst_file as they're in a pair. We explicilty
+ * don't operate on from_dst_file because it's potentially racy
+ * (rp_thread could have reset it in parallel).
*/
- qemu_file_shutdown(ms->rp_state.from_dst_file);
+ qemu_file_shutdown(ms->to_dst_file);
mark_source_rp_bad(ms);
}
trace_await_return_path_close_on_source_joining();
--
2.31.1
[PATCH 3/5] migration: Introduce migration_ioc_[un]register_yank(), Peter Xu, 2021/07/20
[PATCH 4/5] migration: Teach QEMUFile to be QIOChannel-aware, Peter Xu, 2021/07/20