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From: Damien Le Moal <damien.lemoal@wdc.com>
To: Jens Axboe <axboe@kernel.dk>, linux-ide@vger.kernel.org
Cc: linux-block@vger.kernel.org
Subject: [PATCH v6 1/9] libata: fix ata_host_alloc_pinfo()
Date: Thu, 12 Aug 2021 11:43:55 +0900	[thread overview]
Message-ID: <20210812024403.765819-2-damien.lemoal@wdc.com> (raw)
In-Reply-To: <20210812024403.765819-1-damien.lemoal@wdc.com>

Avoid static checkers warnings about a potential NULL pointer
dereference for the port info variable pi. To do so, test that at least
one port info is available on entry to ata_host_alloc_pinfo() and start
the ata port initialization for() loop with pi initialized to the first
port info passed as argument (which is already checked to be non NULL).
Within the for() loop, get the next port info, if it is not NULL,
after initializing the ata port using the previous port info.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
---
 drivers/ata/libata-core.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 61c762961ca8..b237a718ea0f 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -5441,16 +5441,17 @@ struct ata_host *ata_host_alloc_pinfo(struct device *dev,
 	struct ata_host *host;
 	int i, j;
 
+	/* We must have at least one port info */
+	if (!ppi[0])
+		return NULL;
+
 	host = ata_host_alloc(dev, n_ports);
 	if (!host)
 		return NULL;
 
-	for (i = 0, j = 0, pi = NULL; i < host->n_ports; i++) {
+	for (i = 0, j = 0, pi = ppi[0]; i < host->n_ports; i++) {
 		struct ata_port *ap = host->ports[i];
 
-		if (ppi[j])
-			pi = ppi[j++];
-
 		ap->pio_mask = pi->pio_mask;
 		ap->mwdma_mask = pi->mwdma_mask;
 		ap->udma_mask = pi->udma_mask;
@@ -5460,6 +5461,15 @@ struct ata_host *ata_host_alloc_pinfo(struct device *dev,
 
 		if (!host->ops && (pi->port_ops != &ata_dummy_port_ops))
 			host->ops = pi->port_ops;
+
+		/*
+		 * Check that the next port info is not NULL.
+		 * If it is, keep using the current one.
+		 */
+		if (j < n_ports - 1 && ppi[j + 1]) {
+			j++;
+			pi = ppi[j];
+		}
 	}
 
 	return host;
-- 
2.31.1


  reply	other threads:[~2021-08-12  2:44 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-12  2:43 [PATCH v6 0/9] libata cleanups and improvements Damien Le Moal
2021-08-12  2:43 ` Damien Le Moal [this message]
2021-08-12  2:43 ` [PATCH v6 2/9] libata: fix ata_host_start() Damien Le Moal
2021-08-12  2:43 ` [PATCH v6 3/9] libata: simplify ata_scsi_rbuf_fill() Damien Le Moal
2021-08-12  2:43 ` [PATCH v6 4/9] libata: cleanup device sleep capability detection Damien Le Moal
2021-08-12  2:43 ` [PATCH v6 5/9] libata: cleanup ata_dev_configure() Damien Le Moal
2021-08-12  2:44 ` [PATCH v6 6/9] libata: cleanup NCQ priority handling Damien Le Moal
2021-08-12  2:44 ` [PATCH v6 7/9] libata: fix ata_read_log_page() warning Damien Le Moal
2021-08-12  2:44 ` [PATCH v6 8/9] libata: print feature list on device scan Damien Le Moal
2021-08-12  2:44 ` [PATCH v6 9/9] libata: Introduce ncq_prio_supported sysfs sttribute Damien Le Moal

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