From: Ilya Dryomov <idryomov@gmail.com>
To: ceph-devel@vger.kernel.org
Subject: [PATCH 2/3] rbd: call rbd_dev_unprobe() after unwatching and flushing notifies
Date: Tue, 17 Mar 2020 13:04:21 +0100 [thread overview]
Message-ID: <20200317120422.3406-3-idryomov@gmail.com> (raw)
In-Reply-To: <20200317120422.3406-1-idryomov@gmail.com>
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>
---
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 f0ce30a6fc69..e590dc484c18 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -6898,9 +6898,10 @@ static void rbd_print_dne(struct rbd_device *rbd_dev, bool is_snap)
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;
@@ -6947,7 +6948,7 @@ static int rbd_dev_image_probe(struct rbd_device *rbd_dev, int depth)
if (ret) {
if (ret == -ENOENT && !need_watch)
rbd_print_dne(rbd_dev, false);
- goto err_out_watch;
+ goto err_out_probe;
}
/*
@@ -6992,11 +6993,10 @@ 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:
up_write(&rbd_dev->header_rwsem);
if (need_watch)
rbd_unregister_watch(rbd_dev);
+ rbd_dev_unprobe(rbd_dev);
err_out_format:
rbd_dev->image_format = 0;
kfree(rbd_dev->spec->image_id);
--
2.19.2
next prev parent reply other threads:[~2020-03-17 12:04 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-17 12:04 [PATCH 0/3] rbd: fix some issues around flushing notifies Ilya Dryomov
2020-03-17 12:04 ` [PATCH 1/3] rbd: avoid a deadlock on header_rwsem when " Ilya Dryomov
2020-03-17 12:04 ` Ilya Dryomov [this message]
2020-03-17 12:04 ` [PATCH 3/3] rbd: don't test rbd_dev->opts in rbd_dev_image_release() Ilya Dryomov
2020-03-17 16:41 ` [PATCH 0/3] rbd: fix some issues around flushing notifies Jason Dillaman
2020-03-17 17:24 ` Ilya Dryomov
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