Return-path: <linux-wireless-owner@vger.kernel.org>
Received: from mail-oa0-f51.google.com ([209.85.219.51]:40778 "EHLO
	mail-oa0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1751754AbaAORmM (ORCPT
	<rfc822;linux-wireless@vger.kernel.org>);
	Wed, 15 Jan 2014 12:42:12 -0500
Received: by mail-oa0-f51.google.com with SMTP id h16so1067243oag.24
        for <linux-wireless@vger.kernel.org>; Wed, 15 Jan 2014 09:42:11 -0800 (PST)
Message-ID: <52D6C871.7020302@lwfinger.net> (sfid-20140115_184216_299833_288B7826)
Date: Wed, 15 Jan 2014 11:42:09 -0600
From: Larry Finger <Larry.Finger@lwfinger.net>
MIME-Version: 1.0
To: andrea.merello@gmail.com
CC: Bernhard Schiffner <bernhard@schiffner-limbach.de>,
	John Linville <linville@tuxdriver.com>,
	Greg Kroah-Hartman <greg@kroah.com>,
	linux-wireless@vger.kernel.org
Subject: Re: RTL8187SE staging Linux driver
References: <CAN8YU5NTKUtS8+YzmcOSM3=YUX-FSwLTD86F_hXsNdVkw5NEGA@mail.gmail.com>	<522F584E.6000806@lwfinger.net>	<CAN8YU5PCFj-gtQwuuR3fM52YAVTi_5NYPbDVj-KMSzMpXjvFWQ@mail.gmail.com>	<CAN8YU5PGkx9s9deWpFTO_ZtDr-+wDD5cX2JRv1zd1m1Q0BpkCw@mail.gmail.com>	<52D6B31F.8080007@lwfinger.net> <CAN8YU5NLzULTB1H0WMEfyL6jKn8naAM95fm3n0RT02KUXWe68Q@mail.gmail.com>
In-Reply-To: <CAN8YU5NLzULTB1H0WMEfyL6jKn8naAM95fm3n0RT02KUXWe68Q@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Sender: linux-wireless-owner@vger.kernel.org
List-ID: <linux-wireless.vger.kernel.org>

On 01/15/2014 11:22 AM, Andrea Merello wrote:
> Hello,
> Thank you for testing!
>
> This is interesting:
> I ever worked on this patch on an older wireless-testing tree, that
> gave me no oops after lot of time.
>
> Yesterday, before sending you my patch, I ported it to a newer
> wireless-testing, and I did just a quick compile/load test.
> But today I got  panic me too with the new kernel...
>
> I have a serial console over I could capture the the oops..
> I will look at this issue in next days...
>
> 86509.384436] divide error: 0000 [#1] PREEMPT SMP
> [86509.387743] Modules linked in: rtl8180(O) mac80211 cfbfillrect
> cfbimgblt cfbcopyarea drm_kms_helper cfg80211 ttm [last unloaded:
> rtl8180]
> [86509.399253] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G           O
> 3.13.0-rc7-wl+ #16
> [86509.399253] Hardware name: System manufacturer System Product
> Name/M3N78 PRO, BIOS ASUS M3N78 PRO ACPI BIOS Revision 1402 12/04/2009
> [86509.399253] task: ffffffff81c10460 ti: ffffffff81c00000 task.ti:
> ffffffff81c00000
> [86509.428032] RIP: 0010:[<ffffffffa00fdac2>]  [<ffffffffa00fdac2>]
> ieee80211_bss_info_update+0x1c2/0x350 [mac80211]
> [86509.433405] RSP: 0018:ffff88006fc03cb8  EFLAGS: 00010202
> [86509.441368] RAX: 00000000000003e8 RBX: ffff88006fc03d08 RCX: 0000000000000077
> [86509.451441] RDX: 0000000000000000 RSI: ffff880068aa97b0 RDI: 0000000000000000
> [86509.451441] RBP: ffff88006fc03cf8 R08: ffff88006fc03d08 R09: 000000000000000a
> [86509.464969] R10: ffff88006fc03d08 R11: 0000000000000000 R12: ffff880068a93300
> [86509.464969] R13: ffff88006c2db628 R14: ffff880068a93301 R15: ffff880068aa84c0
> [86509.478134] FS:  00007f413fab8800(0000) GS:ffff88006fc00000(0000)
> knlGS:0000000000000000
> [86509.488032] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
> [86509.489400] CR2: 00007f413eedbfc9 CR3: 0000000001c0b000 CR4: 00000000000007f0
> [86509.494704] Stack:
> [86509.494704]  0000000000000000 0000000000000000 0000000020000000
> ffff88006c2db600
> [86509.494704]  ffff880068a93300 ffff880068aa84c0 ffff880068a93300
> ffff880068aa9ac0
> [86509.494704]  ffff88006fc03e38 ffffffffa00fdd8e ffff880068a93324
> 0000000000000053
> [86509.494704] Call Trace:
> [86509.494704]  <IRQ>
> [86509.494704]  [<ffffffffa00fdd8e>] ieee80211_scan_rx+0x13e/0x1a0 [mac80211]
> [86509.494704]  [<ffffffffa0114ff0>] ieee80211_rx+0x700/0x7c0 [mac80211]
> [86509.494704]  [<ffffffffa00f6119>]
> ieee80211_tasklet_handler+0xb9/0xc0 [mac80211]
> [86509.494704]  [<ffffffff8106b3c7>] tasklet_action+0xa7/0xb0
> [86509.494704]  [<ffffffff8106b7fd>] __do_softirq+0xcd/0x1d0
> [86509.494704]  [<ffffffff8106bba6>] irq_exit+0x76/0xa0
> [86509.494704]  [<ffffffff81032dde>] do_IRQ+0x5e/0xd0
> [86509.494704]  [<ffffffff817210ea>] common_interrupt+0x6a/0x6a
> [86509.494704]  <EOI>
> [86509.494704]  [<ffffffff81039198>] ? amd_e400_idle+0x68/0xe0
> [86509.494704]  [<ffffffff810398c6>] arch_cpu_idle+0x16/0x20
> [86509.494704]  [<ffffffff810a0d6d>] cpu_startup_entry+0x11d/0x170
> [86509.494704]  [<ffffffff8171344f>] rest_init+0x7f/0x90
> [86509.494704]  [<ffffffff81cb0d63>] start_kernel+0x307/0x313
> [86509.494704]  [<ffffffff81cb0865>] ? repair_env_string+0x5c/0x5c
> [86509.494704]  [<ffffffff81cb05a3>] x86_64_start_reservations+0x2a/0x2c
> [86509.494704]  [<ffffffff81cb066c>] x86_64_start_kernel+0xc7/0xca
> [86509.494704] Code: 5e 41 5f 5d c3 0f 1f 40 00 45 31 c9 83 e7 20 0f
> 84 9f fe ff ff 45 0f be 4d 21 bf 64 00 00 00 44 89 c8 0f af c7 41 0f
> be 7f 74 99 <f7> ff 41 89 c1 e9 7f fe ff ff 0
> [86509.494704] RIP  [<ffffffffa00fdac2>]
> ieee80211_bss_info_update+0x1c2/0x350 [mac80211]
> [86509.494704]  RSP <ffff88006fc03cb8>
> [86509.654701] ---[ end trace 08e0a7abe35b1caf ]---
> [86509.661368] Kernel panic - not syncing: Fatal exception in interrupt

The divide fault occurs because hw.max_signal was not set in line 75 of 
net/mac80211/scan.c. The failing line is

       signal = (rx_status->signal * 100) / local->hw.max_signal;

I have not yet looked to see where that info comes from in the driver.

Larry