From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 104371DF98B; Mon, 23 Jun 2025 21:12:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750713175; cv=none; b=l7VN/4BAua5e7kWn3mshJdxDO6G8YUwYmZWm2JZ3mT3TmroQ5qZVm2e/qpONMMRapJDvxw6xepbXLiPJpnrklLJQqA3xwkwpL/+lfexY4eg687dFZSFaRgskbGaDgluatUKsmVFsnu7KcUEmTSv06f8De0U0SrEzp3KVkGCN5jY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750713175; c=relaxed/simple; bh=iEWthbzeKpMWyEIKOCKVK/MRP4NkatHK0sckSouOzIM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=H7qQ8dhx379eo3kGdJORz+9NGBH/YR0wtBXFHPRRP2DWPNurtS4UT3ntK2eJ7CihJN5nwFBek3TOD7WIAk30JCeWizXz1D4N0jKCFA86ihMMpQzWlkXwwFYrx7jE+JCz1eAUsztXgvNtiSa02KlGLz5BZFQLpx8OYUffoJSGvSk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=AQ0qwqmt; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="AQ0qwqmt" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9A18CC4CEEA; Mon, 23 Jun 2025 21:12:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1750713174; bh=iEWthbzeKpMWyEIKOCKVK/MRP4NkatHK0sckSouOzIM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AQ0qwqmtp2O9OTDXoaq/RPlespLC/eJ/3cf7s6dpBFVgFhA0fz5/pzdwLyIt6Fnr4 +csTaMS9u7y7p2wVyeP8mY7mLNPKnz9O2hyLwCd78kYfzhMkNYxRW4DDBSMILGO0bG YIbIeQ08zmguP8RiH9GEGF6E5r9n16et6K0ZB/SY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Youssef Samir , Sumit Kumar , Jeff Hugo , Krishna Chaitanya Chundru , Manivannan Sadhasivam Subject: [PATCH 6.6 052/290] bus: mhi: ep: Update read pointer only after buffer is written Date: Mon, 23 Jun 2025 15:05:13 +0200 Message-ID: <20250623130628.568533042@linuxfoundation.org> X-Mailer: git-send-email 2.50.0 In-Reply-To: <20250623130626.910356556@linuxfoundation.org> References: <20250623130626.910356556@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sumit Kumar commit 6f18d174b73d0ceeaa341f46c0986436b3aefc9a upstream. Inside mhi_ep_ring_add_element, the read pointer (rd_offset) is updated before the buffer is written, potentially causing race conditions where the host sees an updated read pointer before the buffer is actually written. Updating rd_offset prematurely can lead to the host accessing an uninitialized or incomplete element, resulting in data corruption. Invoke the buffer write before updating rd_offset to ensure the element is fully written before signaling its availability. Fixes: bbdcba57a1a2 ("bus: mhi: ep: Add support for ring management") cc: stable@vger.kernel.org Co-developed-by: Youssef Samir Signed-off-by: Youssef Samir Signed-off-by: Sumit Kumar Reviewed-by: Jeff Hugo Reviewed-by: Krishna Chaitanya Chundru Reviewed-by: Manivannan Sadhasivam Link: https://patch.msgid.link/20250409-rp_fix-v1-1-8cf1fa22ed28@quicinc.com Signed-off-by: Manivannan Sadhasivam Signed-off-by: Greg Kroah-Hartman --- drivers/bus/mhi/ep/ring.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) --- a/drivers/bus/mhi/ep/ring.c +++ b/drivers/bus/mhi/ep/ring.c @@ -131,19 +131,23 @@ int mhi_ep_ring_add_element(struct mhi_e } old_offset = ring->rd_offset; - mhi_ep_ring_inc_index(ring); dev_dbg(dev, "Adding an element to ring at offset (%zu)\n", ring->rd_offset); + buf_info.host_addr = ring->rbase + (old_offset * sizeof(*el)); + buf_info.dev_addr = el; + buf_info.size = sizeof(*el); + + ret = mhi_cntrl->write_sync(mhi_cntrl, &buf_info); + if (ret) + return ret; + + mhi_ep_ring_inc_index(ring); /* Update rp in ring context */ rp = cpu_to_le64(ring->rd_offset * sizeof(*el) + ring->rbase); memcpy_toio((void __iomem *) &ring->ring_ctx->generic.rp, &rp, sizeof(u64)); - buf_info.host_addr = ring->rbase + (old_offset * sizeof(*el)); - buf_info.dev_addr = el; - buf_info.size = sizeof(*el); - - return mhi_cntrl->write_sync(mhi_cntrl, &buf_info); + return ret; } void mhi_ep_ring_init(struct mhi_ep_ring *ring, enum mhi_ep_ring_type type, u32 id)