From: Ilya Dryomov <idryomov@xxxxxxxxx>
[ Upstream commit 952c48b0ed18919bff7528501e9a3fff8a24f8cd ]
rbd_dev_unprobe() is supposed to undo most of rbd_dev_image_probe(),
including rbd_dev_header_info(), which means that rbd_dev_header_info()
isn't supposed to be called after rbd_dev_unprobe().
However, rbd_dev_image_release() calls rbd_dev_unprobe() before
rbd_unregister_watch(). This is racy because a header update notify
can sneak in:
"rbd unmap" thread ceph-watch-notify worker
rbd_dev_image_release()
rbd_dev_unprobe()
free and zero out header
rbd_watch_cb()
rbd_dev_refresh()
rbd_dev_header_info()
read in header
The same goes for "rbd map" because rbd_dev_image_probe() calls
rbd_dev_unprobe() on errors. In both cases this results in a memory
leak.
Fixes: fd22aef8b47c ("rbd: move rbd_unregister_watch() call into rbd_dev_image_release()")
Signed-off-by: Ilya Dryomov <idryomov@xxxxxxxxx>
Reviewed-by: Jason Dillaman <dillaman@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/block/rbd.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index bab9c546ba334..274beda31c356 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -6933,9 +6933,10 @@ static int rbd_dev_header_name(struct rbd_device *rbd_dev)
static void rbd_dev_image_release(struct rbd_device *rbd_dev)
{
- rbd_dev_unprobe(rbd_dev);
if (rbd_dev->opts)
rbd_unregister_watch(rbd_dev);
+
+ rbd_dev_unprobe(rbd_dev);
rbd_dev->image_format = 0;
kfree(rbd_dev->spec->image_id);
rbd_dev->spec->image_id = NULL;
@@ -6986,7 +6987,7 @@ static int rbd_dev_image_probe(struct rbd_device *rbd_dev, int depth)
ret = rbd_dev_header_info(rbd_dev);
if (ret)
- goto err_out_watch;
+ goto err_out_probe;
/*
* If this image is the one being mapped, we have pool name and
@@ -7035,12 +7036,11 @@ static int rbd_dev_image_probe(struct rbd_device *rbd_dev, int depth)
return 0;
err_out_probe:
- rbd_dev_unprobe(rbd_dev);
-err_out_watch:
if (!depth)
up_write(&rbd_dev->header_rwsem);
if (!depth)
rbd_unregister_watch(rbd_dev);
+ rbd_dev_unprobe(rbd_dev);
err_out_format:
rbd_dev->image_format = 0;
kfree(rbd_dev->spec->image_id);
--
2.20.1
