From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 758D9C624A4 for ; Thu, 3 Sep 2026 11:05:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:MIME-Version:Message-ID:Date:Subject:Cc:To:From:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=R0+chyl53vlDqcHYdyzW6KIs98Ekd5KZC2x9102XgXA=; b=RM8Neb2BeojlVeAZxs8H6s1GKi DmrAPsPq5MW2E3UGh6UT+UZosiGtr+x2FESzeBz1xYeS5YmLrCiNXrxZESLWlvspt3QCEunDMp4s9 3YzAo+ohyN/vMDpG6cCElj51Sk+Ao1ExM2mQUNVDmN1bcX1HrSM7JzX9rhqDcb6JgBX06Y8dnE5EX heJs1GKDhiO6DoMAcYzXao15zGeJ+cP6PP0uxZcJOzkU2d3P1ygx8oPUFz6w1vEk9RL+LYKZTfJhB G/6TUSrSRbEMAE3aL+kzotnAcZ+JctpgRYLFIuXzvHGeBpTR92/jj86n5j7zhO2bow+Eyydm3LZyZ T8NmdI9A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1x25G9-0000000HA7y-1FNj; Thu, 03 Sep 2026 11:05:33 +0000 Received: from ni.piap.pl ([195.187.100.5]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1x25G6-0000000HA7b-1fIl for linux-arm-kernel@lists.infradead.org; Thu, 03 Sep 2026 11:05:32 +0000 Received: from t19.piap.pl (OSB1819.piap.pl [10.0.9.19]) by ni.piap.pl (Postfix) with ESMTPS id 08234C3EEAD7; Thu, 3 Sep 2026 13:05:22 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 ni.piap.pl 08234C3EEAD7 From: =?utf-8?Q?Krzysztof_Ha=C5=82asa?= To: Oleksij Rempel Cc: Pengutronix Kernel Team , Andi Shyti , Frank Li , Sascha Hauer , Fabio Estevam , linux-i2c@vger.kernel.org, imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH] Fix i.MX I2C driver zero byte read kernel panic Date: Thu, 03 Sep 2026 13:05:22 +0200 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260903_040530_594683_E46F7FA5 X-CRM114-Status: UNSURE ( 7.66 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Generally, zero-sized I2C read requests aren't valid. After START, SDA line ownership is transferred to the slave device, and the master cannot terminate transfer at this point. Passing zero-sized read request to i.MX I2C driver causes a NULL pointer dereference in i2c_imx_isr_read_continue() here: i2c_imx->msg->buf[i2c_imx->msg_buf_idx++] =3D imx_i2c_read_reg(i2c_imx, IMX= _I2C_I2DR); Fix it by rejecting zero-sized read transfers. Signed-off-by: Krzysztof Ha=C5=82asa diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c index c44452449a75..1f0f72386912 100644 --- a/drivers/i2c/busses/i2c-imx.c +++ b/drivers/i2c/busses/i2c-imx.c @@ -1637,7 +1637,9 @@ static int i2c_imx_xfer_common(struct i2c_adapter *ad= apter, if (msgs[i].flags & I2C_M_RD) { int block_data =3D msgs->flags & I2C_M_RECV_LEN; =20 - if (atomic) + if (!msgs[i].len) /* invalid, would panic */ + result =3D -EINVAL; + else if (atomic) result =3D i2c_imx_atomic_read(i2c_imx, &msgs[i], is_lastmsg); else if (use_dma && !block_data) result =3D i2c_imx_dma_read(i2c_imx, &msgs[i], is_lastmsg); --=20 Krzysztof "Chris" Ha=C5=82asa Sie=C4=87 Badawcza =C5=81ukasiewicz Przemys=C5=82owy Instytut Automatyki i Pomiar=C3=B3w PIAP Al. Jerozolimskie 202, 02-486 Warszawa