+++ /dev/null
-From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
-From: Fabian Ebner <f.ebner@proxmox.com>
-Date: Wed, 25 May 2022 13:59:38 +0200
-Subject: [PATCH] PVE-Backup: ensure jobs in di_list are referenced
-
-Ensures that qmp_backup_cancel doesn't pick a job that's already been
-freed. With unlucky timings it seems possible that:
-1. job_exit -> job_completed -> job_finalize_single starts
-2. pvebackup_co_complete_stream gets spawned in completion callback
-3. job finalize_single finishes -> job's refcount hits zero -> job is
- freed
-4. qmp_backup_cancel comes in and locks backup_state.backup_mutex
- before pvebackup_co_complete_stream can remove the job from the
- di_list
-5. qmp_backup_cancel will pick a job that's already been freed
-
-Signed-off-by: Fabian Ebner <f.ebner@proxmox.com>
-Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
----
- pve-backup.c | 25 ++++++++++++++++++++-----
- 1 file changed, 20 insertions(+), 5 deletions(-)
-
-diff --git a/pve-backup.c b/pve-backup.c
-index 5bed6f4014..0c34428713 100644
---- a/pve-backup.c
-+++ b/pve-backup.c
-@@ -316,6 +316,14 @@ static void coroutine_fn pvebackup_co_complete_stream(void *opaque)
- }
- }
-
-+ if (di->job) {
-+ AioContext *ctx = di->job->job.aio_context;
-+ aio_context_acquire(ctx);
-+ job_unref(&di->job->job);
-+ di->job = NULL;
-+ aio_context_release(ctx);
-+ }
-+
- // remove self from job list
- backup_state.di_list = g_list_remove(backup_state.di_list, di);
-
-@@ -491,9 +499,12 @@ static void create_backup_jobs_bh(void *opaque) {
- bitmap_mode, false, NULL, &perf, BLOCKDEV_ON_ERROR_REPORT, BLOCKDEV_ON_ERROR_REPORT,
- JOB_DEFAULT, pvebackup_complete_cb, di, backup_state.txn, &local_err);
-
-- aio_context_release(aio_context);
--
- di->job = job;
-+ if (job) {
-+ job_ref(&job->job);
-+ }
-+
-+ aio_context_release(aio_context);
-
- if (!job || local_err) {
- error_setg(errp, "backup_job_create failed: %s",
-@@ -521,12 +532,16 @@ static void create_backup_jobs_bh(void *opaque) {
- di->target = NULL;
- }
-
-- if (!canceled && di->job) {
-+ if (di->job) {
- AioContext *ctx = di->job->job.aio_context;
- aio_context_acquire(ctx);
-- job_cancel_sync(&di->job->job, true);
-+ if (!canceled) {
-+ job_cancel_sync(&di->job->job, true);
-+ canceled = true;
-+ }
-+ job_unref(&di->job->job);
-+ di->job = NULL;
- aio_context_release(ctx);
-- canceled = true;
- }
- }
- }