From patchwork Tue Aug 11 00:42:40 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dhananjay Phadke X-Patchwork-Id: 254913 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-20.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT, USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 328CBC433DF for ; Tue, 11 Aug 2020 00:43:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 022D9206DC for ; Tue, 11 Aug 2020 00:43:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="plhDb8/J" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727077AbgHKAnh (ORCPT ); Mon, 10 Aug 2020 20:43:37 -0400 Received: from linux.microsoft.com ([13.77.154.182]:53224 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727014AbgHKAng (ORCPT ); Mon, 10 Aug 2020 20:43:36 -0400 Received: by linux.microsoft.com (Postfix, from userid 1046) id C51CF20B4908; Mon, 10 Aug 2020 17:43:35 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com C51CF20B4908 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1597106615; bh=AQjpSH/RpqiCpjXXY1Utw/bEGAAvb9t61EHpqwYleBU=; h=From:To:Cc:Subject:Date:From; b=plhDb8/JF858TD3uKcs7VBBnRzGP2DCluApdoJ+H3M8SkhnM7vbfZ5f/hiS5ceisf 0TL6K1gZ6HH1AKZDvuQkO5zYZhcy8b9Ogv8qdWTZJBhP0qhG0i86/x2SC+wAd8IgWK 0O051Ve2FVaIN8JfYc0Pl60wBz0wovLcq4iTlKqQ= From: Dhananjay Phadke To: linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, Wolfram Sang , Ray Jui Cc: Rayagonda Kokatanur , bcm-kernel-feedback-list@broadcom.com, Dhananjay Phadke Subject: [PATCH v3] i2c: iproc: fix race between client unreg and isr Date: Mon, 10 Aug 2020 17:42:40 -0700 Message-Id: <1597106560-79693-1-git-send-email-dphadke@linux.microsoft.com> X-Mailer: git-send-email 1.8.3.1 Sender: linux-i2c-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org When i2c client unregisters, synchronize irq before setting iproc_i2c->slave to NULL. (1) disable_irq() (2) Mask event enable bits in control reg (3) Erase slave address (avoid further writes to rx fifo) (4) Flush tx and rx FIFOs (5) Clear pending event (interrupt) bits in status reg (6) enable_irq() (7) Set client pointer to NULL Unable to handle kernel NULL pointer dereference at virtual address 0000000000000318 [ 371.020421] pc : bcm_iproc_i2c_isr+0x530/0x11f0 [ 371.025098] lr : __handle_irq_event_percpu+0x6c/0x170 [ 371.030309] sp : ffff800010003e40 [ 371.033727] x29: ffff800010003e40 x28: 0000000000000060 [ 371.039206] x27: ffff800010ca9de0 x26: ffff800010f895df [ 371.044686] x25: ffff800010f18888 x24: ffff0008f7ff3600 [ 371.050165] x23: 0000000000000003 x22: 0000000001600000 [ 371.055645] x21: ffff800010f18888 x20: 0000000001600000 [ 371.061124] x19: ffff0008f726f080 x18: 0000000000000000 [ 371.066603] x17: 0000000000000000 x16: 0000000000000000 [ 371.072082] x15: 0000000000000000 x14: 0000000000000000 [ 371.077561] x13: 0000000000000000 x12: 0000000000000001 [ 371.083040] x11: 0000000000000000 x10: 0000000000000040 [ 371.088519] x9 : ffff800010f317c8 x8 : ffff800010f317c0 [ 371.093999] x7 : ffff0008f805b3b0 x6 : 0000000000000000 [ 371.099478] x5 : ffff0008f7ff36a4 x4 : ffff8008ee43d000 [ 371.104957] x3 : 0000000000000000 x2 : ffff8000107d64c0 [ 371.110436] x1 : 00000000c00000af x0 : 0000000000000000 [ 371.115916] Call trace: [ 371.118439] bcm_iproc_i2c_isr+0x530/0x11f0 [ 371.122754] __handle_irq_event_percpu+0x6c/0x170 [ 371.127606] handle_irq_event_percpu+0x34/0x88 [ 371.132189] handle_irq_event+0x40/0x120 [ 371.136234] handle_fasteoi_irq+0xcc/0x1a0 [ 371.140459] generic_handle_irq+0x24/0x38 [ 371.144594] __handle_domain_irq+0x60/0xb8 [ 371.148820] gic_handle_irq+0xc0/0x158 [ 371.152687] el1_irq+0xb8/0x140 [ 371.155927] arch_cpu_idle+0x10/0x18 [ 371.159615] do_idle+0x204/0x290 [ 371.162943] cpu_startup_entry+0x24/0x60 [ 371.166990] rest_init+0xb0/0xbc [ 371.170322] arch_call_rest_init+0xc/0x14 [ 371.174458] start_kernel+0x404/0x430 Fixes: c245d94ed106 ("i2c: iproc: Add multi byte read-write support for slave mode") Signed-off-by: Dhananjay Phadke --- drivers/i2c/busses/i2c-bcm-iproc.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/drivers/i2c/busses/i2c-bcm-iproc.c b/drivers/i2c/busses/i2c-bcm-iproc.c index 8a3c98866fb7..688e92818821 100644 --- a/drivers/i2c/busses/i2c-bcm-iproc.c +++ b/drivers/i2c/busses/i2c-bcm-iproc.c @@ -1078,7 +1078,7 @@ static int bcm_iproc_i2c_unreg_slave(struct i2c_client *slave) if (!iproc_i2c->slave) return -EINVAL; - iproc_i2c->slave = NULL; + disable_irq(iproc_i2c->irq); /* disable all slave interrupts */ tmp = iproc_i2c_rd_reg(iproc_i2c, IE_OFFSET); @@ -1091,6 +1091,17 @@ static int bcm_iproc_i2c_unreg_slave(struct i2c_client *slave) tmp &= ~BIT(S_CFG_EN_NIC_SMB_ADDR3_SHIFT); iproc_i2c_wr_reg(iproc_i2c, S_CFG_SMBUS_ADDR_OFFSET, tmp); + /* flush TX/RX FIFOs */ + tmp = (BIT(S_FIFO_RX_FLUSH_SHIFT) | BIT(S_FIFO_TX_FLUSH_SHIFT)); + iproc_i2c_wr_reg(iproc_i2c, S_FIFO_CTRL_OFFSET, tmp); + + /* clear all pending slave interrupts */ + iproc_i2c_wr_reg(iproc_i2c, IS_OFFSET, ISR_MASK_SLAVE); + + iproc_i2c->slave = NULL; + + enable_irq(iproc_i2c->irq); + return 0; }