Return-path: Received: from mail-wm0-f68.google.com ([74.125.82.68]:36856 "EHLO mail-wm0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934834AbcIUQtk (ORCPT ); Wed, 21 Sep 2016 12:49:40 -0400 From: Christian Lamparter To: gregkh@linuxfoundation.org, Kalle Valo Cc: Christian Lamparter , linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org, Nicolai Stange , Ben Greear Subject: [PATCH v2] carl9170: fix debugfs crashes Date: Wed, 21 Sep 2016 18:49:36 +0200 Message-Id: <238afe4926e979a46013129f8b8db48154e46963.1474476231.git.chunkeey@gmail.com> (sfid-20160921_184945_619573_1626D9DC) In-Reply-To: <1927662.l0xhZ6GL0u@debian64> References: <1927662.l0xhZ6GL0u@debian64> Sender: linux-wireless-owner@vger.kernel.org List-ID: Ben Greear reported: > I see lots of instability as soon as I load up the carl9710 NIC. > My application is going to be poking at it's debugfs files... > > BUG: KASAN: slab-out-of-bounds in carl9170_debugfs_read+0xd5/0x2a0 > [carl9170] at addr 0xffff8801bc1208b0 > Read of size 8 by task btserver/5888 > ======================================================================= > BUG kmalloc-256 (Tainted: G W ): kasan: bad access detected > ----------------------------------------------------------------------- > > INFO: Allocated in seq_open+0x50/0x100 age=2690 cpu=2 pid=772 >... This breakage was caused by the introduction of intermediate fops in debugfs by commit 9fd4dcece43a ("debugfs: prevent access to possibly dead file_operations at file open") Thankfully, the original/real fops are still available in d_fsdata. Reported-by: Ben Greear Signed-off-by: Christian Lamparter Cc: stable # 4.7+ --- drivers/net/wireless/ath/carl9170/debug.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/net/wireless/ath/carl9170/debug.c b/drivers/net/wireless/ath/carl9170/debug.c index 6808db4..ec3a64e 100644 --- a/drivers/net/wireless/ath/carl9170/debug.c +++ b/drivers/net/wireless/ath/carl9170/debug.c @@ -75,7 +75,8 @@ static ssize_t carl9170_debugfs_read(struct file *file, char __user *userbuf, if (!ar) return -ENODEV; - dfops = container_of(file->f_op, struct carl9170_debugfs_fops, fops); + dfops = container_of(debugfs_real_fops(file), + struct carl9170_debugfs_fops, fops); if (!dfops->read) return -ENOSYS; @@ -127,7 +128,8 @@ static ssize_t carl9170_debugfs_write(struct file *file, if (!ar) return -ENODEV; - dfops = container_of(file->f_op, struct carl9170_debugfs_fops, fops); + dfops = container_of(debugfs_real_fops(file), + struct carl9170_debugfs_fops, fops); if (!dfops->write) return -ENOSYS; -- 2.9.3