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Subject[PATCH v2] Fix NULL pointer dereference in bl_free_device().
Date
When bl_parse_deviceid() fails in bl_alloc_deviceid_node() on
blkdev_get_by_*() step we get an pnfs_block_dev struct that is
uninitialized except for bdev field which is set to whatever error
blkdev_get_by_*() returns. bl_free_device() then tries to call
blkdev_put() if bdev is not 0 resulting in a wrong pointer dereference.

Fixing this by making sure bdev is not an error code in bl_free_device().

Signed-off-by: Artem Savkov <asavkov@redhat.com>
---
fs/nfs/blocklayout/dev.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/nfs/blocklayout/dev.c b/fs/nfs/blocklayout/dev.c
index 118252f..57cb800 100644
--- a/fs/nfs/blocklayout/dev.c
+++ b/fs/nfs/blocklayout/dev.c
@@ -33,7 +33,7 @@ bl_free_device(struct pnfs_block_dev *dev)
pr_err("failed to unregister PR key.\n");
}

- if (dev->bdev)
+ if (!IS_ERR_OR_NULL(dev->bdev))
blkdev_put(dev->bdev, FMODE_READ | FMODE_WRITE);
}
}
--
2.5.5
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