From: Ilya Dryomov idryomov@gmail.com
[ 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@gmail.com Reviewed-by: Jason Dillaman dillaman@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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);