linux-kernel - [PATCH AUTOSEL 4.14 20/21] i2c: core: fix use after free in of_i2c

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Date:   Fri, 22 Nov 2019 14:49:30 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Wen Yang <wenyang@...ux.alibaba.com>,
        Wolfram Sang <wsa@...-dreams.de>,
        Sasha Levin <sashal@...nel.org>, linux-i2c@...r.kernel.org
Subject: [PATCH AUTOSEL 4.14 20/21] i2c: core: fix use after free in of_i2c_notify

From: Wen Yang <wenyang@...ux.alibaba.com>

[ Upstream commit a4c2fec16f5e6a5fee4865e6e0e91e2bc2d10f37 ]

We can't use "adap->dev" after it has been freed.

Fixes: 5bf4fa7daea6 ("i2c: break out OF support into separate file")
Signed-off-by: Wen Yang <wenyang@...ux.alibaba.com>
Signed-off-by: Wolfram Sang <wsa@...-dreams.de>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/i2c/i2c-core-of.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/i2c-core-of.c b/drivers/i2c/i2c-core-of.c
index 8d474bb1dc157..17d727e0b8424 100644
--- a/drivers/i2c/i2c-core-of.c
+++ b/drivers/i2c/i2c-core-of.c
@@ -238,14 +238,14 @@ static int of_i2c_notify(struct notifier_block *nb, unsigned long action,
 		}
 
 		client = of_i2c_register_device(adap, rd->dn);
-		put_device(&adap->dev);
-
 		if (IS_ERR(client)) {
 			dev_err(&adap->dev, "failed to create client for '%pOF'\n",
 				 rd->dn);
+			put_device(&adap->dev);
 			of_node_clear_flag(rd->dn, OF_POPULATED);
 			return notifier_from_errno(PTR_ERR(client));
 		}
+		put_device(&adap->dev);
 		break;
 	case OF_RECONFIG_CHANGE_REMOVE:
 		/* already depopulated? */
-- 
2.20.1