Subject: [PATCH 22/58] net/wan: fix a double free in x25_asy_open_tty()

From: Cong Wang <[email-masked]>
Date: Sat, 29 Dec 2018 13:56:37 -0800

[ Upstream commit d5c7c745f254c6cb98b3b3f15fe789b8bd770c72 ]

When x25_asy_open() fails, it already cleans up by itself,
so its caller doesn't need to free the memory again.

It seems we still have to call x25_asy_free() to clear the SLF_INUSE
bit, so just set these pointers to NULL after kfree().

Reported-and-tested-by: [email-masked]
Fixes: 3b780bed3138 ("x25_asy: Free x25_asy on x25_asy_open() failure.")
Signed-off-by: Cong Wang <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
---
 drivers/net/wan/x25_asy.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/wan/x25_asy.c b/drivers/net/wan/x25_asy.c
index 74c06a5f586f..4f25c2d8fff0 100644
--- a/drivers/net/wan/x25_asy.c
+++ b/drivers/net/wan/x25_asy.c
@@ -486,8 +486,10 @@ static int x25_asy_open(struct net_device *dev)
 
 	/* Cleanup */
 	kfree(sl->xbuff);
+	sl->xbuff = NULL;
 noxbuff:
 	kfree(sl->rbuff);
+	sl->rbuff = NULL;
 norbuff:
 	return -ENOMEM;
 }
-- 
2.20.1