From 9b6d90e2085ca2ce72ef9ea78658bf270855e62e Mon Sep 17 00:00:00 2001
From: Zhou Qingyang <zhou1615@umn.edu>
Date: Tue, 25 Jan 2022 00:45:25 +0800
Subject: [PATCH] ata: pata_platform: Fix a NULL pointer dereference in __pata_platform_probe()
Git-commit: 9b6d90e2085ca2ce72ef9ea78658bf270855e62e
Patch-mainline: v5.17-rc2
References: git-fixes

In __pata_platform_probe(), devm_kzalloc() is assigned to ap->ops and
there is a dereference of it right after that, which could introduce a
NULL pointer dereference bug.

Fix this by adding a NULL check of ap->ops.

This bug was found by a static analyzer.

Builds with 'make allyesconfig' show no new warnings,
and our static analyzer no longer warns about this code.

Fixes: f3d5e4f18dba ("ata: pata_of_platform: Allow to use 16-bit wide data transfer")
Signed-off-by: Zhou Qingyang <zhou1615@umn.edu>
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/ata/pata_platform.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/ata/pata_platform.c b/drivers/ata/pata_platform.c
index 028329428b75..87c7c90676ca 100644
--- a/drivers/ata/pata_platform.c
+++ b/drivers/ata/pata_platform.c
@@ -128,6 +128,8 @@ int __pata_platform_probe(struct device *dev, struct resource *io_res,
 	ap = host->ports[0];
 
 	ap->ops = devm_kzalloc(dev, sizeof(*ap->ops), GFP_KERNEL);
+	if (!ap->ops)
+		return -ENOMEM;
 	ap->ops->inherits = &ata_sff_port_ops;
 	ap->ops->cable_detect = ata_cable_unknown;
 	ap->ops->set_mode = pata_platform_set_mode;
-- 
2.31.1