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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, Dongliang Mu <mudongliangabcd@gmail.com>,
        Christoph Hellwig <hch@lst.de>,
        Damien Le Moal <damien.lemoal@opensource.wdc.com>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.15 106/247] scsi: sd: Fix potential NULL pointer dereference
Date:   Mon, 13 Jun 2022 12:10:08 +0200
Message-Id: <20220613094926.172750343@linuxfoundation.org>
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References: <20220613094922.843438024@linuxfoundation.org>
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From: Damien Le Moal <damien.lemoal@opensource.wdc.com>

[ Upstream commit 05fbde3a77a4f1d62e4c4428f384288c1f1a0be5 ]

If sd_probe() sees an early error before sdkp->device is initialized,
sd_zbc_release_disk() is called. This causes a NULL pointer dereference
when sd_is_zoned() is called inside that function. Avoid this by removing
the call to sd_zbc_release_disk() in sd_probe() error path.

This change is safe and does not result in zone information memory leakage
because the zone information for a zoned disk is allocated only when
sd_revalidate_disk() is called, at which point sdkp->disk_dev is fully set,
resulting in sd_disk_release() being called when needed to cleanup a disk
zone information using sd_zbc_release_disk().

Link: https://lore.kernel.org/r/20220601062544.905141-2-damien.lemoal@opensource.wdc.com
Fixes: 89d947561077 ("sd: Implement support for ZBC devices")
Reported-by: Dongliang Mu <mudongliangabcd@gmail.com>
Suggested-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/scsi/sd.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index a713babaee0f..de6640ad1943 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -3480,7 +3480,6 @@ static int sd_probe(struct device *dev)
  out_put:
 	put_disk(gd);
  out_free:
-	sd_zbc_release_disk(sdkp);
 	kfree(sdkp);
  out:
 	scsi_autopm_put_device(sdp);
-- 
2.35.1