[pve-devel] [PATCH qemu] fix #4101: acquire job's aio context before calling job_unref

Fabian Ebner f.ebner at proxmox.com
Thu Jun 9 13:55:38 CEST 2022


Otherwise, we might not run into an abort via bdrv_co_yield_to_drain()
(can at least happen when a disk with iothread is used):
> #0  0x00007fef4f5dece1 __GI_raise (libc.so.6 + 0x3bce1)
> #1  0x00007fef4f5c8537 __GI_abort (libc.so.6 + 0x25537)
> #2  0x00005641bce3c71f error_exit (qemu-system-x86_64 + 0x80371f)
> #3  0x00005641bce3d02b qemu_mutex_unlock_impl (qemu-system-x86_64 + 0x80402b)
> #4  0x00005641bcd51655 bdrv_co_yield_to_drain (qemu-system-x86_64 + 0x718655)
> #5  0x00005641bcd52de8 bdrv_do_drained_begin (qemu-system-x86_64 + 0x719de8)
> #6  0x00005641bcd47e07 blk_drain (qemu-system-x86_64 + 0x70ee07)
> #7  0x00005641bcd498cd blk_unref (qemu-system-x86_64 + 0x7108cd)
> #8  0x00005641bcd31e6f block_job_free (qemu-system-x86_64 + 0x6f8e6f)
> #9  0x00005641bcd32d65 job_unref (qemu-system-x86_64 + 0x6f9d65)
> #10 0x00005641bcd93b3d pvebackup_co_complete_stream (qemu-system-x86_64 + 0x75ab3d)
> #11 0x00005641bce4e353 coroutine_trampoline (qemu-system-x86_64 + 0x815353)

Signed-off-by: Fabian Ebner <f.ebner at proxmox.com>
---
 ...ensure-jobs-in-di_list-are-referenced.patch | 18 ++++++++++++------
 ...id-segfault-issues-upon-backup-cancel.patch |  6 +++---
 2 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/debian/patches/pve/0055-PVE-Backup-ensure-jobs-in-di_list-are-referenced.patch b/debian/patches/pve/0055-PVE-Backup-ensure-jobs-in-di_list-are-referenced.patch
index db86632..ebb7919 100644
--- a/debian/patches/pve/0055-PVE-Backup-ensure-jobs-in-di_list-are-referenced.patch
+++ b/debian/patches/pve/0055-PVE-Backup-ensure-jobs-in-di_list-are-referenced.patch
@@ -17,26 +17,29 @@ freed. With unlucky timings it seems possible that:
 Signed-off-by: Fabian Ebner <f.ebner at proxmox.com>
 Signed-off-by: Wolfgang Bumiller <w.bumiller at proxmox.com>
 ---
- pve-backup.c | 13 +++++++++++++
- 1 file changed, 13 insertions(+)
+ pve-backup.c | 19 +++++++++++++++++++
+ 1 file changed, 19 insertions(+)
 
 diff --git a/pve-backup.c b/pve-backup.c
-index 5bed6f4014..cd45e66a61 100644
+index 5bed6f4014..7b094e5018 100644
 --- a/pve-backup.c
 +++ b/pve-backup.c
-@@ -316,6 +316,11 @@ static void coroutine_fn pvebackup_co_complete_stream(void *opaque)
+@@ -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);
++        aio_context_release(ctx);
 +        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) {
+@@ -494,6 +502,9 @@ static void create_backup_jobs_bh(void *opaque) {
          aio_context_release(aio_context);
  
          di->job = job;
@@ -46,13 +49,16 @@ index 5bed6f4014..cd45e66a61 100644
  
          if (!job || local_err) {
              error_setg(errp, "backup_job_create failed: %s",
-@@ -528,6 +536,11 @@ static void create_backup_jobs_bh(void *opaque) {
+@@ -528,6 +539,14 @@ static void create_backup_jobs_bh(void *opaque) {
                  aio_context_release(ctx);
                  canceled = true;
              }
 +
 +            if (di->job) {
++                AioContext *ctx = di->job->job.aio_context;
++                aio_context_acquire(ctx);
 +                job_unref(&di->job->job);
++                aio_context_release(ctx);
 +                di->job = NULL;
 +            }
          }
diff --git a/debian/patches/pve/0056-PVE-Backup-avoid-segfault-issues-upon-backup-cancel.patch b/debian/patches/pve/0056-PVE-Backup-avoid-segfault-issues-upon-backup-cancel.patch
index e0c91e6..a5de91d 100644
--- a/debian/patches/pve/0056-PVE-Backup-avoid-segfault-issues-upon-backup-cancel.patch
+++ b/debian/patches/pve/0056-PVE-Backup-avoid-segfault-issues-upon-backup-cancel.patch
@@ -37,10 +37,10 @@ Signed-off-by: Wolfgang Bumiller <w.bumiller at proxmox.com>
  1 file changed, 39 insertions(+), 22 deletions(-)
 
 diff --git a/pve-backup.c b/pve-backup.c
-index cd45e66a61..be21027dad 100644
+index 7b094e5018..26f9aad3d8 100644
 --- a/pve-backup.c
 +++ b/pve-backup.c
-@@ -352,15 +352,42 @@ static void pvebackup_complete_cb(void *opaque, int ret)
+@@ -355,15 +355,42 @@ static void pvebackup_complete_cb(void *opaque, int ret)
  
  /*
   * job_cancel(_sync) does not like to be called from coroutines, so defer to
@@ -89,7 +89,7 @@ index cd45e66a61..be21027dad 100644
      aio_co_enter(data->ctx, data->co);
  }
  
-@@ -381,22 +408,12 @@ void coroutine_fn qmp_backup_cancel(Error **errp)
+@@ -384,22 +411,12 @@ void coroutine_fn qmp_backup_cancel(Error **errp)
          proxmox_backup_abort(backup_state.pbs, "backup canceled");
      }
  
-- 
2.30.2





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