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[PATCH 2/2] migration/multifd: Fix multifd_send_setup cleanup when chann
From: |
Fabiano Rosas |
Subject: |
[PATCH 2/2] migration/multifd: Fix multifd_send_setup cleanup when channel creation fails |
Date: |
Thu, 1 Aug 2024 14:41:01 -0300 |
When a channel fails to create, the code currently just returns. This
is wrong for two reasons:
1) Channel n+1 will not get to initialize it's semaphores, leading to
an assert when terminate_threads tries to post to it:
qemu-system-x86_64: ../util/qemu-thread-posix.c:92:
qemu_mutex_lock_impl: Assertion `mutex->initialized' failed.
2) (theoretical) If channel n-1 already started creation it will
defeat the purpose of the channels_created logic which is in place
to avoid migrate_fd_cleanup() to run while channels are still being
created.
This cannot really happen today because the current failure cases
for multifd_new_send_channel_create() are all synchronous,
resulting from qio_channel_file_new_path() getting a bad
filename. This would hit all channels equally.
But I don't want to set a trap for future people, so have all
channels try to create (even if failing), and only fail after the
channels_created semaphore has been posted.
While here, remove the error_report_err call. There's one already at
migrate_fd_cleanup later on.
Cc: qemu-stable@nongnu.org
Reported-by: Jim Fehlig <jfehlig@suse.com>
Fixes: bd8b0a8f82 ("migration/multifd: Move multifd_send_setup error handling
in to the function")
Signed-off-by: Fabiano Rosas <farosas@suse.de>
---
migration/multifd.c | 26 +++++++++++++++-----------
1 file changed, 15 insertions(+), 11 deletions(-)
diff --git a/migration/multifd.c b/migration/multifd.c
index 0b4cbaddfe..552f9723c8 100644
--- a/migration/multifd.c
+++ b/migration/multifd.c
@@ -1156,7 +1156,6 @@ static bool multifd_new_send_channel_create(gpointer
opaque, Error **errp)
bool multifd_send_setup(void)
{
MigrationState *s = migrate_get_current();
- Error *local_err = NULL;
int thread_count, ret = 0;
uint32_t page_count = MULTIFD_PACKET_SIZE / qemu_target_page_size();
bool use_packets = multifd_use_packets();
@@ -1177,6 +1176,7 @@ bool multifd_send_setup(void)
for (i = 0; i < thread_count; i++) {
MultiFDSendParams *p = &multifd_send_state->params[i];
+ Error *local_err = NULL;
qemu_sem_init(&p->sem, 0);
qemu_sem_init(&p->sem_sync, 0);
@@ -1196,7 +1196,8 @@ bool multifd_send_setup(void)
p->write_flags = 0;
if (!multifd_new_send_channel_create(p, &local_err)) {
- return false;
+ migrate_set_error(s, local_err);
+ ret = -1;
}
}
@@ -1209,24 +1210,27 @@ bool multifd_send_setup(void)
qemu_sem_wait(&multifd_send_state->channels_created);
}
+ if (ret) {
+ goto err;
+ }
+
for (i = 0; i < thread_count; i++) {
MultiFDSendParams *p = &multifd_send_state->params[i];
+ Error *local_err = NULL;
ret = multifd_send_state->ops->send_setup(p, &local_err);
if (ret) {
- break;
+ migrate_set_error(s, local_err);
+ goto err;
}
}
- if (ret) {
- migrate_set_error(s, local_err);
- error_report_err(local_err);
- migrate_set_state(&s->state, MIGRATION_STATUS_SETUP,
- MIGRATION_STATUS_FAILED);
- return false;
- }
-
return true;
+
+err:
+ migrate_set_state(&s->state, MIGRATION_STATUS_SETUP,
+ MIGRATION_STATUS_FAILED);
+ return false;
}
bool multifd_recv(void)
--
2.35.3
- [PATCH 2/2] migration/multifd: Fix multifd_send_setup cleanup when channel creation fails,
Fabiano Rosas <=