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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, kernel test robot <lkp@intel.com>,
        Damien Le Moal <damien.lemoal@wdc.com>,
        Hannes Reinecke <hare@suse.de>, Jens Axboe <axboe@kernel.dk>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.4 021/144] libata: fix ata_host_start()
Date:   Mon, 13 Sep 2021 15:13:22 +0200
Message-Id: <20210913131048.664739711@linuxfoundation.org>
In-Reply-To: <20210913131047.974309396@linuxfoundation.org>
References: <20210913131047.974309396@linuxfoundation.org>
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From: Damien Le Moal <damien.lemoal@wdc.com>

[ Upstream commit 355a8031dc174450ccad2a61c513ad7222d87a97 ]

The loop on entry of ata_host_start() may not initialize host->ops to a
non NULL value. The test on the host_stop field of host->ops must then
be preceded by a check that host->ops is not NULL.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Link: https://lore.kernel.org/r/20210816014456.2191776-3-damien.lemoal@wdc.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/ata/libata-core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index f67b3fb33d57..7788af0ca109 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -6394,7 +6394,7 @@ int ata_host_start(struct ata_host *host)
 			have_stop = 1;
 	}
 
-	if (host->ops->host_stop)
+	if (host->ops && host->ops->host_stop)
 		have_stop = 1;
 
 	if (have_stop) {
-- 
2.30.2