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 6B1AC2727E2; Mon, 13 Apr 2026 16:12:13 +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=1776096733; cv=none; b=pTTOKlYVhh6k7TMhPr3DB/V14UaEeAw/j1/XAyUKmionJgfTzKbWobf6CoRAUi/6zCJZvgH2uSe2NzXT5Dds0/jEoPT+cRhxgZ+cxRidSprkJEzyi75I+ZNojg8z+CWiTQmi9dxUQrkusENxj3FUI1r4CCvJG/CAkS/R5w1UCW0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776096733; c=relaxed/simple; bh=m4HPKKHlkyv5qBCJQq9iLl6edooG6YUJOlu7DZ2mEPo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=WzI51k42BQWpRTEbvHGFf2kqxJQU4/YS6lPso5gumAtlQrmAihndkegim9vSGACrbAR3uU6UtsFcN4fB7n6Bt3yYRVAl6i5DEz2FaOLADZVGuurOGVfjZ6iOnkzP42WliTmhow+P7u7FDIm40t4EO5CN8WxO6clI1wPaBaaJBe4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=IW1V69B3; 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="IW1V69B3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 02CC2C2BCAF; Mon, 13 Apr 2026 16:12:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1776096733; bh=m4HPKKHlkyv5qBCJQq9iLl6edooG6YUJOlu7DZ2mEPo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IW1V69B33vJO4JtBB0aCs3gD78NFj0E0iczEmRqI1GpqYlCMp7Poegibt48rN9qgs AaJTxk4u99ECbm7eP9gO9+9PP+vznl1s2LSEkr3pwwRsg+EuUnAo8DxEKzKzjgeEBW frOamzazCgxXPjhKQ82lZdx5CaaGPLdrA93DO9CQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Pengpeng Hou , Paolo Abeni Subject: [PATCH 6.12 41/70] nfc: pn533: allocate rx skb before consuming bytes Date: Mon, 13 Apr 2026 18:00:36 +0200 Message-ID: <20260413155729.713055558@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260413155728.181580293@linuxfoundation.org> References: <20260413155728.181580293@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 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Pengpeng Hou commit c71ba669b570c7b3f86ec875be222ea11dacb352 upstream. pn532_receive_buf() reports the number of accepted bytes to the serdev core. The current code consumes bytes into recv_skb and may already hand a complete frame to pn533_recv_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: c656aa4c27b1 ("nfc: pn533: add UART phy driver") Cc: stable@vger.kernel.org Signed-off-by: Pengpeng Hou Link: https://patch.msgid.link/20260405094003.3-pn533-v2-pengpeng@iscas.ac.cn Signed-off-by: Paolo Abeni Signed-off-by: Greg Kroah-Hartman --- drivers/nfc/pn533/uart.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) --- a/drivers/nfc/pn533/uart.c +++ b/drivers/nfc/pn533/uart.c @@ -211,6 +211,13 @@ static size_t pn532_receive_buf(struct s del_timer(&dev->cmd_timeout); for (i = 0; i < count; i++) { + if (!dev->recv_skb) { + dev->recv_skb = alloc_skb(PN532_UART_SKB_BUFF_LEN, + GFP_KERNEL); + if (!dev->recv_skb) + return i; + } + if (unlikely(!skb_tailroom(dev->recv_skb))) skb_trim(dev->recv_skb, 0); @@ -219,9 +226,7 @@ static size_t pn532_receive_buf(struct s continue; pn533_recv_frame(dev->priv, dev->recv_skb, 0); - dev->recv_skb = alloc_skb(PN532_UART_SKB_BUFF_LEN, GFP_KERNEL); - if (!dev->recv_skb) - return 0; + dev->recv_skb = NULL; } return i;