From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: Fabian Ebner 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 Signed-off-by: Wolfgang Bumiller --- pve-backup.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/pve-backup.c b/pve-backup.c index 5bed6f4014..cd45e66a61 100644 --- a/pve-backup.c +++ b/pve-backup.c @@ -316,6 +316,11 @@ static void coroutine_fn pvebackup_co_complete_stream(void *opaque) } } + if (di->job) { + job_unref(&di->job->job); + di->job = NULL; + } + // remove self from job list backup_state.di_list = g_list_remove(backup_state.di_list, di); @@ -494,6 +499,9 @@ static void create_backup_jobs_bh(void *opaque) { aio_context_release(aio_context); di->job = job; + if (job) { + job_ref(&job->job); + } if (!job || local_err) { error_setg(errp, "backup_job_create failed: %s", @@ -528,6 +536,11 @@ static void create_backup_jobs_bh(void *opaque) { aio_context_release(ctx); canceled = true; } + + if (di->job) { + job_unref(&di->job->job); + di->job = NULL; + } } }