Return-path: <linux-wireless-owner@vger.kernel.org>
Received: from smtp.nokia.com ([192.100.122.230]:31069 "EHLO
	mgw-mx03.nokia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1751383Ab0FJFVm (ORCPT
	<rfc822;linux-wireless@vger.kernel.org>);
	Thu, 10 Jun 2010 01:21:42 -0400
Subject: Re: [PATCHv4] mac80211: Fix circular locking dependency in ARP
 filter handling
From: Juuso Oikarinen <juuso.oikarinen@nokia.com>
To: ext reinette chatre <reinette.chatre@intel.com>
Cc: "linville@tuxdriver.com" <linville@tuxdriver.com>,
	"linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>
In-Reply-To: <1276126067.1835.15473.camel@rchatre-DESK>
References: <1276080206-29562-1-git-send-email-juuso.oikarinen@nokia.com>
	 <1276126067.1835.15473.camel@rchatre-DESK>
Content-Type: text/plain; charset="UTF-8"
Date: Thu, 10 Jun 2010 08:20:55 +0300
Message-ID: <1276147255.5277.34285.camel@wimaxnb.nmp.nokia.com>
Mime-Version: 1.0
Sender: linux-wireless-owner@vger.kernel.org
List-ID: <linux-wireless.vger.kernel.org>

Hi,

On Thu, 2010-06-10 at 01:27 +0200, ext reinette chatre wrote:
> Hi Juuso,
> 
> On Wed, 2010-06-09 at 03:43 -0700, Juuso Oikarinen wrote:
> > There is a circular locking dependency when configuring the
> > hardware ARP filters on association, occurring when flushing the mac80211
> > workqueue.
> 
> I am currently running with latest wireless-testing (HEAD
> 5e3283c821c3a7750b1f7bd982b10ebdbab0e155) with your patch "mac80211: Add
> netif state checking to ieee80211_ifa_changed" also applied.
> 
> This hunk below does not seem to match with what is currently in
> wireless-testing.
> 
> > @@ -2116,19 +2129,9 @@ static enum work_done_result ieee80211_assoc_done(struct ieee80211_work *wk,
> >                         cfg80211_send_assoc_timeout(wk->sdata->dev,
> >                                                     wk->filter_ta);
> >                         return WORK_DONE_DESTROY;
> > -#ifdef CONFIG_INET
> > -               } else {
> > -                       mutex_unlock(&wk->sdata->u.mgd.mtx);
> > -
> > -                       /*
> > -                        * configure ARP filter IP addresses to the driver,
> > -                        * intentionally outside the mgd mutex.
> > -                        */
> > -                       rtnl_lock();
> > -                       ieee80211_set_arp_filter(wk->sdata);
> > -                       rtnl_unlock();
> > -#endif
> >                 }
> > +
> > +               mutex_unlock(&wk->sdata->u.mgd.mtx);
> >         }
> > 
> >         cfg80211_send_rx_assoc(wk->sdata->dev, skb->data, skb->len);
> > --
> 
> I made some modifications to get the patch to apply to wireless-testing,
> not sure what should be done here since the difference seems
> significant.

There was a small bug in regard of the mutex_unlock after Linville added
those CONFIG_INET thingies. Apparently he had fixed that in parallel,
hence the conflict.

> Even so, I tested your new patch and for some reason the BUG returned
> (even though I am now running with "mac80211: Add netif state checking
> to ieee80211_ifa_changed"

This is curious. In your source (mine does not seem to fully match what
you are using) what is the BUG that is getting triggered, main.c:437 ?

-Juuso

> Here is what I get:
> 
> [  390.153170] ------------[ cut here ]------------
> [  390.156016] kernel BUG at /home/wifi/iwlwifi-2.6/net/mac80211/main.c:437!
> [  390.156016] invalid opcode: 0000 [#1] SMP
> [  390.156016] last sysfs file: /sys/devices/virtual/misc/rfkill/dev
> [  390.156016] CPU 0
> [  390.156016] Modules linked in: iwl3945(+) iwlcore mac80211 cfg80211 rfkill binfmt_misc sbs
>  sbshc ipv6 evdev psmouse serio_raw pcspkr pegasus mii battery container processor video ac b
> utton output intel_agp ext3 jbd mbcache sg sd_mod sr_mod cdrom ahci libahci libata ehci_hcd u
> hci_hcd scsi_mod usbcore thermal fan thermal_sys
> [  390.156016]
> [  390.156016] Pid: 5171, comm: modprobe Not tainted 2.6.35-rc2-wl-64031-g07c6e79 #211 To be
> filled by O.E.M./Montevina platform
> [  390.156016] RIP: 0010:[<ffffffffa026faf2>]  [<ffffffffa026faf2>] ieee80211_alloc_hw+0x502/
> 0x520 [mac80211]
> [  390.156016] RSP: 0018:ffff880025a9fc78  EFLAGS: 00010246
> [  390.156016] RAX: ffff8800241319c0 RBX: ffff8800241302e0 RCX: 0000000000000001
> [  390.156016] RDX: ffffffffa02647a0 RSI: ffffffffa02647a8 RDI: ffffffffa0264a34
> [  390.156016] RBP: ffff880025a9fc98 R08: 0000000000000008 R09: ffffffff8154a5f8
> [  390.156016] R10: 0000000000000001 R11: 0000000000000000 R12: ffff8800241305a0
> [  390.156016] R13: ffffffffa032dfc0 R14: ffff88003b6b6000 R15: ffff880025fa2180
> [  390.156016] FS:  00007f634f2cd6f0(0000) GS:ffff880002000000(0000) knlGS:0000000000000000
> [  390.156016] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
> [  390.156016] CR2: 00007fffc7cf9040 CR3: 000000002552a000 CR4: 00000000000006f0
> [  390.156016] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [  390.156016] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
> [  390.156016] Process modprobe (pid: 5171, threadinfo ffff880025a9e000, task ffff880002442df
> 0)
> [  390.156016] Stack:
> [  390.156016]  ffffffffa032e460 ffffffffa032e460 ffff88003b6b6000 ffff88003b6b6000
> [  390.156016] <0> ffff880025a9fcb8 ffffffffa02d553e ffffffffa032e460 ffff88003b6b6088
> [  390.156016] <0> ffff880025a9fd38 ffffffffa03131a7 0000000000000246 ffffffffa032df48
> [  390.156016] Call Trace:
> [  390.156016]  [<ffffffffa02d553e>] iwl_alloc_all+0x1e/0x50 [iwlcore]
> [  390.156016]  [<ffffffffa03131a7>] iwl3945_pci_probe+0x27/0x1640 [iwl3945]
> [  390.156016]  [<ffffffff81348a56>] ? _raw_spin_unlock+0x26/0x30
> [  390.156016]  [<ffffffff811d4ca0>] ? pci_match_device+0x20/0xd0
> [  390.156016]  [<ffffffff811d4b52>] local_pci_probe+0x12/0x20
> [  390.156016]  [<ffffffff811d5c60>] pci_device_probe+0x80/0xa0
> [  390.156016]  [<ffffffff8124fe7b>] ? driver_sysfs_add+0x6b/0x90
> [  390.156016]  [<ffffffff8124ffb5>] driver_probe_device+0x95/0x1d0
> [  390.156016]  [<ffffffff8125018b>] __driver_attach+0x9b/0xb0
> [  390.156016]  [<ffffffff812500f0>] ? __driver_attach+0x0/0xb0
> [  390.156016]  [<ffffffff8124f65b>] bus_for_each_dev+0x6b/0xa0
> [  390.156016]  [<ffffffff8124fe0c>] driver_attach+0x1c/0x20
> [  390.156016]  [<ffffffff8124edb5>] bus_add_driver+0x1b5/0x300
> [  390.156016]  [<ffffffffa0091000>] ? iwl3945_init+0x0/0x80 [iwl3945]
> [  390.156016]  [<ffffffff8125049c>] driver_register+0x7c/0x170
> [  390.156016]  [<ffffffffa0091000>] ? iwl3945_init+0x0/0x80 [iwl3945]
> [  390.156016]  [<ffffffff811d5f1a>] __pci_register_driver+0x6a/0xf0
> [  390.156016]  [<ffffffffa0091000>] ? iwl3945_init+0x0/0x80 [iwl3945]
> [  390.156016]  [<ffffffffa009104a>] iwl3945_init+0x4a/0x80 [iwl3945]
> [  390.156016]  [<ffffffff810001d8>] do_one_initcall+0x38/0x190
> [  390.156016]  [<ffffffff8107ffbe>] sys_init_module+0xbe/0x220
> [  390.156016]  [<ffffffff81002c6b>] system_call_fastpath+0x16/0x1b
> [  390.156016] Code: c7 c6 52 fa 2a a0 49 89 84 24 a0 03 00 00 49 89 84 24 a8 03 00 00 e8 2e
> 64 f5 e0 4c 89 e0 5b 41 5c 41 5d 41 5e c9 c3 0f 0b eb fe <0f> 0b eb fe 0f 0b eb fe 0f 0b eb f
> e 0f 0b eb fe 0f 0b eb fe 0f
> [  390.156016] RIP  [<ffffffffa026faf2>] ieee80211_alloc_hw+0x502/0x520 [mac80211]
> [  390.156016]  RSP <ffff880025a9fc78>
> [  390.515754] ---[ end trace ac1678fc227a51d2 ]---
> 
> Reinette
> 
>