From patchwork Tue Mar 17 11:59:29 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pravas Kumar Panda X-Patchwork-Id: 11442613 X-Patchwork-Delegate: kvalo@adurom.com Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 7C2FC14DD for ; Tue, 17 Mar 2020 12:00:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5CEF020736 for ; Tue, 17 Mar 2020 12:00:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="tYH8UjY+" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726552AbgCQMA3 (ORCPT ); Tue, 17 Mar 2020 08:00:29 -0400 Received: from mail26.static.mailgun.info ([104.130.122.26]:27842 "EHLO mail26.static.mailgun.info" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726428AbgCQMA3 (ORCPT ); Tue, 17 Mar 2020 08:00:29 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1584446428; h=Message-Id: Date: Subject: Cc: To: From: Sender; bh=0V4JeM7uMHP3PDzj6H7teVS8H+e3C0yYmlguWTAzDd4=; b=tYH8UjY+CmJiH6GPseZDp1tFO83W0XZE38gwy2cvQW10Ly6Kuj0z5qKPDSaHDjEhkdp7fyY7 XIa+nax7dlY3pVh1VBKlS2quF3AuU2G9VLNgR6FrbDCYvA8yst5mQfjVHsC4S6biWHf/sM0D oQEiCieKsmLDOS7A753u6V9J7UU= X-Mailgun-Sending-Ip: 104.130.122.26 X-Mailgun-Sid: WyI3YTAwOSIsICJsaW51eC13aXJlbGVzc0B2Z2VyLmtlcm5lbC5vcmciLCAiYmU5ZTRhIl0= Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by mxa.mailgun.org with ESMTP id 5e70bbcf.7f52d9b2fdc0-smtp-out-n01; Tue, 17 Mar 2020 12:00:15 -0000 (UTC) Received: by smtp.codeaurora.org (Postfix, from userid 1001) id B6BECC433BA; Tue, 17 Mar 2020 12:00:15 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-caf-mail-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=2.0 tests=ALL_TRUSTED,SPF_NONE autolearn=unavailable autolearn_force=no version=3.4.0 Received: from periyasa-linux.qualcomm.com (blr-c-bdr-fw-01_GlobalNAT_AllZones-Outside.qualcomm.com [103.229.19.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: kumarpan) by smtp.codeaurora.org (Postfix) with ESMTPSA id CCC39C433CB; Tue, 17 Mar 2020 12:00:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org CCC39C433CB Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=none smtp.mailfrom=kumarpan@codeaurora.org From: Pravas Kumar Panda To: ath11k@lists.infradead.org Cc: linux-wireless@vger.kernel.org, Pravas Kumar Panda Subject: [PATCH] ath11k: Adding proper validation before accessing tx_stats Date: Tue, 17 Mar 2020 17:29:29 +0530 Message-Id: <1584446369-7021-1-git-send-email-kumarpan@codeaurora.org> X-Mailer: git-send-email 2.7.4 Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org Before dumping tx_stats proper validation was not been taken care of. Due to which we were encountering null pointer dereference(kernel panic). This scenario will arise when a station is getting disconnected and we are changing the STA state by ath11k_mac_op_sta_state and assigning tx_stats as NULL and after this the mac80211 will destroy the debugfs entry from where we are trying to read the stats. If anyone tries to dump tx_stats for that STA in between setting tx_stats to NULL and debugfs file removal without checking the NULL value it will run into a NULL pointer exception. Proceeding with the analysis of "ARM Kernel Panic". The APSS crash happened due to OOPS on CPU 3. Crash Signature : Unable to handle kernel NULL pointer dereference at virtual address 00000360 During the crash, PC points to "ath11k_debug_htt_stats_init+0x16ac/0x1acc [ath11k]" LR points to "ath11k_debug_htt_stats_init+0x1688/0x1acc [ath11k]". The Backtrace obtained is as follows: [] ath11k_debug_htt_stats_init+0x16ac/0x1acc [ath11k] [] do_loop_readv_writev+0x60/0xa4 [] do_readv_writev+0xd8/0x19c [] vfs_readv+0x34/0x48 [] default_file_splice_read+0x1a8/0x2e4 [] do_splice_to+0x78/0x98 [] splice_direct_to_actor+0xb0/0x1a4 [] do_splice_direct+0x84/0xa8 [] do_sendfile+0x160/0x2a4 [] SyS_sendfile64+0xb4/0xc8 Signed-off-by: Pravas Kumar Panda --- drivers/net/wireless/ath/ath11k/debugfs_sta.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/net/wireless/ath/ath11k/debugfs_sta.c b/drivers/net/wireless/ath/ath11k/debugfs_sta.c index 872f3ef..389dac2 100644 --- a/drivers/net/wireless/ath/ath11k/debugfs_sta.c +++ b/drivers/net/wireless/ath/ath11k/debugfs_sta.c @@ -219,6 +219,9 @@ static ssize_t ath11k_dbg_sta_dump_tx_stats(struct file *file, const int size = 2 * 4096; char *buf; + if (!arsta->tx_stats) + return -ENOENT; + buf = kzalloc(size, GFP_KERNEL); if (!buf) return -ENOMEM;