libata: fix ata_host_start()

[ 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>

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index db1d86af21b4db2322f9f98765c9309db0e45fdf..d9b1c3e95592cf7a2c7cbb87a0ecc61678e04cbd 100644 (file)
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -6412,7 +6412,7 @@ 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) {