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| author |   Ilya Dryomov <idryomov@gmail.com> | 2020-03-16 15:52:54 +0100 |
|---|---|---|
| committer | Ilya Dryomov <idryomov@gmail.com> | 2020-04-13 08:55:49 +0200 |
| commit | 952c48b0ed18919bff7528501e9a3fff8a24f8cd (patch) | |
| tree | cb1c4416ad298503d23abd3298da76bfbf3c5634 /drivers/block/rbd.c | |
| parent | rbd: avoid a deadlock on header_rwsem when flushing notifies (diff) | |
| download | linux-dev-952c48b0ed18919bff7528501e9a3fff8a24f8cd.tar.xz linux-dev-952c48b0ed18919bff7528501e9a3fff8a24f8cd.zip | |
rbd: call rbd_dev_unprobe() after unwatching and flushing notifies
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>
Diffstat (limited to '')
| -rw-r--r-- | drivers/block/rbd.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c index ff2377e6d12c..7aec8bc5df6e 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; @@ -6950,7 +6951,7 @@ 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; } /* @@ -6995,12 +6996,11 @@ 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 (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); |