From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from xc.sipsolutions.net ([83.246.72.84]:56320 "EHLO sipsolutions.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932361AbZJEJQk (ORCPT ); Mon, 5 Oct 2009 05:16:40 -0400 Subject: [PATCH] wext: let get_wireless_stats() sleep From: Johannes Berg To: John Linville Cc: Miles Lane , linux-wireless , netdev Content-Type: text/plain; charset="UTF-8" Date: Mon, 05 Oct 2009 11:15:59 +0200 Message-Id: <1254734159.22426.6.camel@johannes.local> Mime-Version: 1.0 Sender: linux-wireless-owner@vger.kernel.org List-ID: A number of drivers (recently including cfg80211-based ones) assume that all wireless handlers, including statistics, can sleep and they often also implicitly assume that the rtnl is held around their invocation. This is almost always true now except when reading from sysfs: BUG: sleeping function called from invalid context at kernel/mutex.c:280 in_atomic(): 1, irqs_disabled(): 0, pid: 10450, name: head 2 locks held by head/10450: #0: (&buffer->mutex){+.+.+.}, at: [] sysfs_read_file+0x24/0xf4 #1: (dev_base_lock){++.?..}, at: [] wireless_show+0x1a/0x4c Pid: 10450, comm: head Not tainted 2.6.32-rc3 #1 Call Trace: [] __might_sleep+0xf0/0xf7 [] mutex_lock_nested+0x1a/0x33 [] wdev_lock+0xd/0xf [cfg80211] [] cfg80211_wireless_stats+0x45/0x12d [cfg80211] [] get_wireless_stats+0x16/0x1c [] wireless_show+0x2a/0x4c Fix this by using the rtnl instead of dev_base_lock. Reported-by: Miles Lane Signed-off-by: Johannes Berg --- net/core/net-sysfs.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- wireless-testing.orig/net/core/net-sysfs.c 2009-10-05 11:09:56.000000000 +0200 +++ wireless-testing/net/core/net-sysfs.c 2009-10-05 11:10:52.000000000 +0200 @@ -366,13 +366,13 @@ static ssize_t wireless_show(struct devi const struct iw_statistics *iw; ssize_t ret = -EINVAL; - read_lock(&dev_base_lock); + rtnl_lock(); if (dev_isalive(dev)) { iw = get_wireless_stats(dev); if (iw) ret = (*format)(iw, buf); } - read_unlock(&dev_base_lock); + rtnl_unlock(); return ret; }