The patch 0f20972f7bf6 moves a common cleanup code to a separate function.
Unfortunatelly, the patch changes the order of cleanup, so that it
destroys the srcu structure io_barrier before destroying the workqueue.
The function that is executed on the workqueue (dm_wq_work) uses the srcu
structure, thus it may use it after being freed. That results in a crash
in the LVM test mirror-vgreduce-removemissing.sh.
Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
Fixes: 0f20972f7bf6 ("dm: factor out a common cleanup_mapped_device()")
---
drivers/md/dm.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
Index: linux-4.2-rc1/drivers/md/dm.c
===================================================================
--- linux-4.2-rc1.orig/drivers/md/dm.c 2015-07-09 22:08:12.000000000 +0200
+++ linux-4.2-rc1/drivers/md/dm.c 2015-07-10 21:20:50.000000000 +0200
@@ -2367,8 +2367,6 @@ static void dm_init_old_md_queue(struct
static void cleanup_mapped_device(struct mapped_device *md)
{
- cleanup_srcu_struct(&md->io_barrier);
-
if (md->wq)
destroy_workqueue(md->wq);
if (md->kworker_task)
@@ -2380,6 +2378,8 @@ static void cleanup_mapped_device(struct
if (md->bs)
bioset_free(md->bs);
+ cleanup_srcu_struct(&md->io_barrier);
+
if (md->disk) {
spin_lock(&_minor_lock);
md->disk->private_data = NULL;
--
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