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 2C57617A31C; Mon, 20 Apr 2026 15:59:27 +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=1776700767; cv=none; b=o9smsPGDHCvcuVwIyDf9GSpXj+1qxSetifixiOO7Pa1qzaPgugW8lf5BlhhOr5lOFL4kgxBxNhWFCYMVH3n73MyvWDU7NXgmWNU2/92EzDzSDJD5fLbTVJS8k26VlHL8s8PSGf63nCO+xGd8atbB+sxqIRbt2JXpbYHBih+8Qkc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776700767; c=relaxed/simple; bh=GXx/tTYdlkLLOFjOrBizO1EHDLoP1JA2zl7Z4tXFfJc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=iJ2odWUW6nVVfsYTFs+mTTDp6rl73e4cR7rPCKRtps0izynDdxB3a/Rbz7M2xpY21gRWrUJWYFfDXP+zx2ErTJlIDu/wc500aBlDnqCWpi0/0KzyhOGppvjsGoGBDoA/jInIoPl5rsulLi9qEvDsbqQB48XUxJm2DUT0jbyXWGw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=t/Gwr+lv; 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="t/Gwr+lv" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B11D0C19425; Mon, 20 Apr 2026 15:59:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1776700767; bh=GXx/tTYdlkLLOFjOrBizO1EHDLoP1JA2zl7Z4tXFfJc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=t/Gwr+lvZOy8R4K1NDIcg2vN7hwhfGvRx//x+le2w2865aikDbcR2CxFweuGWGI78 Jo/GSME4z7vIaGWyl6rWWKNaUvN2OlL1/LAqwFUGWTz/5nKMPOib5nsAO6ADOgCEpt OoRDup3m8THvFHGNgRmBVfTc7zqKWvh0XNBz8sII= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Pengpeng Hou , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.18 080/198] nfc: s3fwrn5: allocate rx skb before consuming bytes Date: Mon, 20 Apr 2026 17:40:59 +0200 Message-ID: <20260420153938.489363985@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260420153935.605963767@linuxfoundation.org> References: <20260420153935.605963767@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Pengpeng Hou [ Upstream commit 5c14a19d5b1645cce1cb1252833d70b23635b632 ] s3fwrn82_uart_read() reports the number of accepted bytes to the serdev core. The current code consumes bytes into recv_skb and may already deliver a complete frame before allocating a fresh receive buffer. If that alloc_skb() fails, the callback returns 0 even though it has already consumed bytes, and it leaves recv_skb as NULL for the next receive callback. That breaks the receive_buf() accounting contract and can also lead to a NULL dereference on the next skb_put_u8(). Allocate the receive skb lazily before consuming the next byte instead. If allocation fails, return the number of bytes already accepted. Fixes: 3f52c2cb7e3a ("nfc: s3fwrn5: Support a UART interface") Signed-off-by: Pengpeng Hou Link: https://patch.msgid.link/20260402042148.65236-1-pengpeng@iscas.ac.cn Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- drivers/nfc/s3fwrn5/uart.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/nfc/s3fwrn5/uart.c b/drivers/nfc/s3fwrn5/uart.c index 9c09c10c2a464..4ee481bd7e965 100644 --- a/drivers/nfc/s3fwrn5/uart.c +++ b/drivers/nfc/s3fwrn5/uart.c @@ -58,6 +58,12 @@ static size_t s3fwrn82_uart_read(struct serdev_device *serdev, size_t i; for (i = 0; i < count; i++) { + if (!phy->recv_skb) { + phy->recv_skb = alloc_skb(NCI_SKB_BUFF_LEN, GFP_KERNEL); + if (!phy->recv_skb) + return i; + } + skb_put_u8(phy->recv_skb, *data++); if (phy->recv_skb->len < S3FWRN82_NCI_HEADER) @@ -69,9 +75,7 @@ static size_t s3fwrn82_uart_read(struct serdev_device *serdev, s3fwrn5_recv_frame(phy->common.ndev, phy->recv_skb, phy->common.mode); - phy->recv_skb = alloc_skb(NCI_SKB_BUFF_LEN, GFP_KERNEL); - if (!phy->recv_skb) - return 0; + phy->recv_skb = NULL; } return i; -- 2.53.0