86 lines
3.0 KiB
Diff
86 lines
3.0 KiB
Diff
From 287d4267dcb2d5f262dba7f6e7f35dcd294b622a Mon Sep 17 00:00:00 2001
|
|
From: Kevin Wolf <kwolf@redhat.com>
|
|
Date: Wed, 10 Oct 2018 20:22:09 +0100
|
|
Subject: job: Avoid deadlocks in job_completed_txn_abort()
|
|
|
|
RH-Author: Kevin Wolf <kwolf@redhat.com>
|
|
Message-id: <20181010202213.7372-31-kwolf@redhat.com>
|
|
Patchwork-id: 82622
|
|
O-Subject: [RHEL-8 qemu-kvm PATCH 40/44] job: Avoid deadlocks in job_completed_txn_abort()
|
|
Bugzilla: 1637976
|
|
RH-Acked-by: Max Reitz <mreitz@redhat.com>
|
|
RH-Acked-by: John Snow <jsnow@redhat.com>
|
|
RH-Acked-by: Thomas Huth <thuth@redhat.com>
|
|
|
|
Amongst others, job_finalize_single() calls the .prepare/.commit/.abort
|
|
callbacks of the individual job driver. Recently, their use was adapted
|
|
for all block jobs so that they involve code calling AIO_WAIT_WHILE()
|
|
now. Such code must be called under the AioContext lock for the
|
|
respective job, but without holding any other AioContext lock.
|
|
|
|
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
|
|
Reviewed-by: Max Reitz <mreitz@redhat.com>
|
|
(cherry picked from commit 644f3a29bd4974aefd46d2adb5062d86063c8a50)
|
|
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
|
|
Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
|
|
---
|
|
job.c | 16 +++++++++++-----
|
|
1 file changed, 11 insertions(+), 5 deletions(-)
|
|
|
|
diff --git a/job.c b/job.c
|
|
index 00a1cd1..0b02186 100644
|
|
--- a/job.c
|
|
+++ b/job.c
|
|
@@ -718,6 +718,7 @@ static void job_cancel_async(Job *job, bool force)
|
|
|
|
static void job_completed_txn_abort(Job *job)
|
|
{
|
|
+ AioContext *outer_ctx = job->aio_context;
|
|
AioContext *ctx;
|
|
JobTxn *txn = job->txn;
|
|
Job *other_job;
|
|
@@ -731,23 +732,26 @@ static void job_completed_txn_abort(Job *job)
|
|
txn->aborting = true;
|
|
job_txn_ref(txn);
|
|
|
|
- /* We are the first failed job. Cancel other jobs. */
|
|
- QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
|
|
- ctx = other_job->aio_context;
|
|
- aio_context_acquire(ctx);
|
|
- }
|
|
+ /* We can only hold the single job's AioContext lock while calling
|
|
+ * job_finalize_single() because the finalization callbacks can involve
|
|
+ * calls of AIO_WAIT_WHILE(), which could deadlock otherwise. */
|
|
+ aio_context_release(outer_ctx);
|
|
|
|
/* Other jobs are effectively cancelled by us, set the status for
|
|
* them; this job, however, may or may not be cancelled, depending
|
|
* on the caller, so leave it. */
|
|
QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
|
|
if (other_job != job) {
|
|
+ ctx = other_job->aio_context;
|
|
+ aio_context_acquire(ctx);
|
|
job_cancel_async(other_job, false);
|
|
+ aio_context_release(ctx);
|
|
}
|
|
}
|
|
while (!QLIST_EMPTY(&txn->jobs)) {
|
|
other_job = QLIST_FIRST(&txn->jobs);
|
|
ctx = other_job->aio_context;
|
|
+ aio_context_acquire(ctx);
|
|
if (!job_is_completed(other_job)) {
|
|
assert(job_is_cancelled(other_job));
|
|
job_finish_sync(other_job, NULL, NULL);
|
|
@@ -756,6 +760,8 @@ static void job_completed_txn_abort(Job *job)
|
|
aio_context_release(ctx);
|
|
}
|
|
|
|
+ aio_context_acquire(outer_ctx);
|
|
+
|
|
job_txn_unref(txn);
|
|
}
|
|
|
|
--
|
|
1.8.3.1
|
|
|