Return-path: Received: from mail-ua0-f177.google.com ([209.85.217.177]:32861 "EHLO mail-ua0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751464AbcHPRr3 (ORCPT ); Tue, 16 Aug 2016 13:47:29 -0400 Received: by mail-ua0-f177.google.com with SMTP id 74so134001427uau.0 for ; Tue, 16 Aug 2016 10:47:19 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <1471057200-58166-2-git-send-email-pgynther@google.com> References: <1471057200-58166-1-git-send-email-pgynther@google.com> <1471057200-58166-2-git-send-email-pgynther@google.com> From: Petri Gynther Date: Tue, 16 Aug 2016 10:47:18 -0700 Message-ID: (sfid-20160816_194750_695234_66EF8020) Subject: Re: [PATCH 2/2] mwifiex: fix unaligned read in mwifiex_config_scan() To: linux-wireless@vger.kernel.org Cc: kvalo@codeaurora.org, David Miller , Joe Perches , Amitkumar Karwar , Petri Gynther Content-Type: text/plain; charset=UTF-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Fri, Aug 12, 2016 at 8:00 PM, Petri Gynther wrote: > $ iwconfig mlan0 essid MySSID > [ 36.930000] Path: /sbin/iwconfig > [ 36.930000] CPU: 0 PID: 203 Comm: iwconfig Not tainted 4.7.0 #2 > [ 36.940000] task: 866f83a0 ti: 866a6000 task.ti: 866a6000 > [ 36.940000] > [ECR ]: 0x00230400 => Misaligned r/w from 0x8677f403 > [ 36.960000] [EFA ]: 0x8677f403 > [ 36.960000] [BLINK ]: mwifiex_scan_networks+0x17a/0x198c [mwifiex] > [ 36.960000] [ERET ]: mwifiex_scan_networks+0x18a/0x198c [mwifiex] > [ 36.980000] [STAT32]: 0x00000206 : K E2 E1 > [ 36.980000] BTA: 0x700736e2 SP: 0x866a7d0c FP: 0x5faddc84 > [ 37.000000] LPS: 0x806a37ec LPE: 0x806a37fa LPC: 0x00000000 > [ 37.000000] r00: 0x8677f401 r01: 0x8668aa08 r02: 0x00000001 > r03: 0x00000000 r04: 0x8668b600 r05: 0x8677f406 > r06: 0x8702b600 r07: 0x00000000 r08: 0x8702b600 > r09: 0x00000000 r10: 0x870b3b00 r11: 0x00000000 > r12: 0x00000000 > [ 37.040000] > [ 37.040000] Stack Trace: > [ 37.040000] mwifiex_scan_networks+0x18a/0x198c [mwifiex] > > Root cause: > mwifiex driver calls is_zero_ether_addr() against byte-aligned address: > > drivers/net/wireless/marvell/mwifiex/fw.h: > struct mwifiex_scan_cmd_config { > /* > * BSS mode to be sent in the firmware command > */ > u8 bss_mode; > > /* Specific BSSID used to filter scan results in the firmware */ > u8 specific_bssid[ETH_ALEN]; > > ... > } __packed; > > drivers/net/wireless/marvell/mwifiex/scan.c: > mwifiex_config_scan(..., struct mwifiex_scan_cmd_config *scan_cfg_out, ...) > ... > if (adapter->ext_scan && > !is_zero_ether_addr(scan_cfg_out->specific_bssid)) { > ... > } > > Since firmware-related struct mwifiex_scan_cmd_config cannot be changed, > we need to use the new function is_zero_ether_addr_unaligned() here. > > This is v2 of the original patch: > [PATCH] Modify is_zero_ether_addr() to handle byte-aligned addresses > > Per Joe's suggestion -- instead of modifying is_zero_ether_addr() -- > add is_zero_ether_addr_unaligned() and use it where needed. > > Cc: Kalle Valo > Cc: David S. Miller > Cc: Joe Perches > Cc: Amitkumar Karwar > Signed-off-by: Petri Gynther > --- > drivers/net/wireless/marvell/mwifiex/scan.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/net/wireless/marvell/mwifiex/scan.c b/drivers/net/wireless/marvell/mwifiex/scan.c > index bc5e52c..d648c88 100644 > --- a/drivers/net/wireless/marvell/mwifiex/scan.c > +++ b/drivers/net/wireless/marvell/mwifiex/scan.c > @@ -883,7 +883,8 @@ mwifiex_config_scan(struct mwifiex_private *priv, > sizeof(scan_cfg_out->specific_bssid)); > > if (adapter->ext_scan && > - !is_zero_ether_addr(scan_cfg_out->specific_bssid)) { > + !is_zero_ether_addr_unaligned( > + scan_cfg_out->specific_bssid)) { Any comments? Is this approach of adding is_zero_ether_addr_unaligned() fine? We already have similar routine ether_addr_equal_unaligned(). I don't see much benefit making a local, aligned copy here. It would have to use memcpy w/ byte operations anyways and then still run is_zero_ether_addr(). Amitkumar -- Is it possible to modify struct mwifiex_scan_cmd_config {} and align specific_bssid field to u16 boundary? > bssid_tlv = > (struct mwifiex_ie_types_bssid_list *)tlv_pos; > bssid_tlv->header.type = cpu_to_le16(TLV_TYPE_BSSID); > -- > 2.8.0.rc3.226.g39d4020 >