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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Niklas Cassel <niklas.cassel@wdc.com>,
        Christoph Hellwig <hch@lst.de>
Subject: [PATCH 5.6 66/73] nvme: prevent double free in nvme_alloc_ns() error handling
Date:   Mon,  4 May 2020 19:58:09 +0200
Message-Id: <20200504165510.184799022@linuxfoundation.org>
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From: Niklas Cassel <niklas.cassel@wdc.com>

commit 132be62387c7a72a38872676c18b0dfae264adb8 upstream.

When jumping to the out_put_disk label, we will call put_disk(), which will
trigger a call to disk_release(), which calls blk_put_queue().

Later in the cleanup code, we do blk_cleanup_queue(), which will also call
blk_put_queue().

Putting the queue twice is incorrect, and will generate a KASAN splat.

Set the disk->queue pointer to NULL, before calling put_disk(), so that the
first call to blk_put_queue() will not free the queue.

The second call to blk_put_queue() uses another pointer to the same queue,
so this call will still free the queue.

Fixes: 85136c010285 ("lightnvm: simplify geometry enumeration")
Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/nvme/host/core.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -3580,6 +3580,8 @@ static int nvme_alloc_ns(struct nvme_ctr
 
 	return 0;
  out_put_disk:
+	/* prevent double queue cleanup */
+	ns->disk->queue = NULL;
 	put_disk(ns->disk);
  out_unlink_ns:
 	mutex_lock(&ctrl->subsys->lock);