Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 5.4 033/118] rbd: call rbd_dev_unprobe() after unwatching and flushing notifies | Date | Wed, 22 Apr 2020 11:56:34 +0200 |
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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); -- 2.20.1
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