[PATCH] driver: core: Fix list corruption after device_del()

From: Takashi Iwai <tiwai@suse.de>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J . Wysocki" <rafael@kernel.org>, linux-kernel@vger.kernel.org
Subject: [PATCH] driver: core: Fix list corruption after device_del()
Date: Tue,  8 Dec 2020 20:03:26 +0100	[thread overview]
Message-ID: <20201208190326.27531-1-tiwai@suse.de> (raw)

The device_links_purge() function (called from device_del()) tries to
remove the links.needs_suppliers list entry, but it's using
list_del(), hence it doesn't initialize after the removal.  This is OK
for normal cases where device_del() is called via device_destroy().
However, it's not guaranteed that the device object will be really
deleted soon after device_del().  In a minor case like HD-audio codec
reconfiguration that re-initializes the device after device_del(), it
may lead to a crash by the corrupted list entry.

As a simple fix, replace list_del() with list_del_init() in order to
make the list intact after the device_del() call.

Fixes: e2ae9bcc4aaa ("driver core: Add support for linking devices during device addition")
Cc: <stable@vger.kernel.org>
BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=209207
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 drivers/base/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index d661ada1518f..e8cb66093f21 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -1386,7 +1386,7 @@ static void device_links_purge(struct device *dev)
 		return;
 
 	mutex_lock(&wfs_lock);
-	list_del(&dev->links.needs_suppliers);
+	list_del_init(&dev->links.needs_suppliers);
 	mutex_unlock(&wfs_lock);
 
 	/*
-- 
2.26.2

