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[23.128.96.18]) by mx.google.com with ESMTP id i26si11105255eja.98.2020.07.20.10.41.09; Mon, 20 Jul 2020 10:41:33 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@broadcom.com header.s=google header.b=Te0Y+PvE; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=QUARANTINE sp=QUARANTINE dis=NONE) header.from=broadcom.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729675AbgGTRkZ (ORCPT + 99 others); Mon, 20 Jul 2020 13:40:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57594 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728876AbgGTRkY (ORCPT ); Mon, 20 Jul 2020 13:40:24 -0400 Received: from mail-wm1-x344.google.com (mail-wm1-x344.google.com [IPv6:2a00:1450:4864:20::344]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7E898C0619D2 for ; Mon, 20 Jul 2020 10:40:24 -0700 (PDT) Received: by mail-wm1-x344.google.com with SMTP id w3so322667wmi.4 for ; Mon, 20 Jul 2020 10:40:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=broadcom.com; s=google; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-transfer-encoding:content-language; bh=hNTtSnwQCPYkI9vVfOrEJLQRwWlzgGEc02Rqyshk+Hw=; b=Te0Y+PvEO5oNpWcaCTFDOBSRHyVqXRNcCBjyZqDeeObYUqqdGcGttbA6SiV13LiTRM jDRSdrsv1zfBWv+aHt0XqJT9ANTr9V5H0d7arLpfEDQkpIjNGKqJ7XLCUQpjiQbwIJVE mATPyPyTeGi6yzCK76m2kDlZZ6FCjXI1ZRuYQ= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding :content-language; bh=hNTtSnwQCPYkI9vVfOrEJLQRwWlzgGEc02Rqyshk+Hw=; b=A5uleN8jPgiiSlmXbcHxMxO4OkJVHDD3vCTJoHDFXk88UKhd/f7K9Ea+LsmayZ7AGX bheUpMU8qUDPRjDYPUrdz5cVTX0mMqhOG8JTpGrXF/o6rYvGoCz2hh+YOHa0Pzw+Y7qt wQ2zRGsuNMMG46ojmCPzYX090kRt8ZMf7bzTQbi+QK1LSDodNEDbyJjPz1toTWuJhzht s2SjwKPp0tH4SneAB3JFkUsJochZY55Eo0f7RX5qOjHtFimnlDJUEMg2hH+y+Idf/QYe 3K2/N0t9XBOW60T+kxqU4Og7rg5uy8E43gU/xW3I63u6Qs7AJjJXxzte+NAhjTL0tvtp xGaA== X-Gm-Message-State: AOAM533/Vh8L76HCafSjWvKuQcI0tJ1ouUlHFeas3S1j3xSvPaeU2oaV uiET7lvNcXfS/mpi9rSvBgbfeg== X-Received: by 2002:a1c:1b90:: with SMTP id b138mr392710wmb.21.1595266822926; Mon, 20 Jul 2020 10:40:22 -0700 (PDT) Received: from [10.136.13.65] ([192.19.228.250]) by smtp.gmail.com with ESMTPSA id d13sm34202869wrq.89.2020.07.20.10.40.20 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 20 Jul 2020 10:40:22 -0700 (PDT) Subject: Re: [PATCH] i2c: iproc: fix race between client unreg and isr To: Rayagonda Kokatanur , Dhananjay Phadke Cc: linux-i2c , Linux Kernel Mailing List , Wolfram Sang , Ray Jui , BCM Kernel Feedback References: <1595115599-100054-1-git-send-email-dphadke@linux.microsoft.com> From: Scott Branden Message-ID: Date: Mon, 20 Jul 2020 10:40:16 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org looks good. On 2020-07-19 12:59 a.m., Rayagonda Kokatanur wrote: > On Sun, Jul 19, 2020 at 5:10 AM Dhananjay Phadke > wrote: >> When i2c client unregisters, synchronize irq before setting >> iproc_i2c->slave 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 Acked-by: Scott Branden >> --- >> drivers/i2c/busses/i2c-bcm-iproc.c | 5 +++-- >> 1 file changed, 3 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/i2c/busses/i2c-bcm-iproc.c b/drivers/i2c/busses/i2c-bcm-iproc.c >> index b58224b7b..37d2a79e7 100644 >> --- a/drivers/i2c/busses/i2c-bcm-iproc.c >> +++ b/drivers/i2c/busses/i2c-bcm-iproc.c >> @@ -1074,14 +1074,15 @@ static int bcm_iproc_i2c_unreg_slave(struct i2c_client *slave) >> if (!iproc_i2c->slave) >> return -EINVAL; >> >> - iproc_i2c->slave = NULL; >> - >> /* disable all slave interrupts */ >> tmp = iproc_i2c_rd_reg(iproc_i2c, IE_OFFSET); >> tmp &= ~(IE_S_ALL_INTERRUPT_MASK << >> IE_S_ALL_INTERRUPT_SHIFT); >> iproc_i2c_wr_reg(iproc_i2c, IE_OFFSET, tmp); >> >> + synchronize_irq(iproc_i2c->irq); >> + iproc_i2c->slave = NULL; >> + >> /* Erase the slave address programmed */ >> tmp = iproc_i2c_rd_reg(iproc_i2c, S_CFG_SMBUS_ADDR_OFFSET); >> tmp &= ~BIT(S_CFG_EN_NIC_SMB_ADDR3_SHIFT); > Looks good to me. Thank you for the patch. > Reviewed-by: Rayagonda Kokatanur > > Regards, > Rayagonda