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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 v7 01/11] libata: fix ata_host_alloc_pinfo()
Date: Mon, 16 Aug 2021 10:44:46 +0900	[thread overview]
Message-ID: <20210816014456.2191776-2-damien.lemoal@wdc.com> (raw)
In-Reply-To: <20210816014456.2191776-1-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:[~2021-08-16  1:45 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-16  1:44 [PATCH v7 00/11] libata cleanups and improvements Damien Le Moal
2021-08-16  1:44 ` Damien Le Moal [this message]
2021-08-16  5:53   ` [PATCH v7 01/11] libata: fix ata_host_alloc_pinfo() Hannes Reinecke
2021-08-16 11:29   ` James Bottomley
2021-08-16 11:43     ` Damien Le Moal
2021-08-16  1:44 ` [PATCH v7 02/11] libata: fix ata_host_start() Damien Le Moal
2021-08-16  1:44 ` [PATCH v7 03/11] libata: simplify ata_scsi_rbuf_fill() Damien Le Moal
2021-08-16  1:44 ` [PATCH v7 04/11] libata: cleanup device sleep capability detection Damien Le Moal
2021-08-16  1:44 ` [PATCH v7 05/11] libata: cleanup ata_dev_configure() Damien Le Moal
2021-08-16  1:44 ` [PATCH v7 06/11] libata: cleanup NCQ priority handling Damien Le Moal
2021-08-16  1:44 ` [PATCH v7 07/11] libata: fix ata_read_log_page() warning Damien Le Moal
2021-08-16  1:44 ` [PATCH v7 08/11] libata: print feature list on device scan Damien Le Moal
2021-08-16  1:44 ` [PATCH v7 09/11] libata: Introduce ncq_prio_supported sysfs sttribute Damien Le Moal
2021-08-16  5:54   ` Hannes Reinecke
2021-08-16  1:44 ` [PATCH v7 10/11] docs: sysfs-block-device: improve ncq_prio_enable documentation Damien Le Moal
2021-08-16  5:54   ` Hannes Reinecke
2021-08-16  1:44 ` [PATCH v7 11/11] docs: sysfs-block-device: document ncq_prio_supported Damien Le Moal
2021-08-16  5:55   ` Hannes Reinecke
2021-08-18  9:54 ` [PATCH v7 00/11] libata cleanups and improvements Damien Le Moal
2021-08-18 13:20 ` Jens Axboe
2021-08-18 21:53   ` Damien Le Moal

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