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 7C25925332E; Mon, 13 Apr 2026 16:08:26 +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=1776096506; cv=none; b=Ls45DVDvA3Sbw6B/MuWoCMvu1mfdlW/bryvPzO0bCyQ/sPvwLiA8xbR2XEQ3D3K5Jxx9Nh5o7ubBpvgViP4FZsYogty+vRBTQ8V8Sfs9CzRpcmdutk5IA7XNA82rJYfLpyqmnhldZkpIlD/OayIoaWhRDstzG3p0N0bDGlm/WZM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776096506; c=relaxed/simple; bh=VUCfXGotR8gRq17l8mszLnBbBhLK/pAwUwELVgP5YQI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=k1WKDoda8uuSQOZpy0FmYFwyfv8TS3TlnVo09UmhiOy+JSqrl6hRt7KVh+hovF5N+N75m8STRl+uDTD7CW5be/0vCAgOgE3FA9oYAq8GC1X/HOZ1V91ttEfH/gLiRJh8bTV/wzbKxS9Py5P+GHPS3/zHEFZUAa1DNODJc6/0CzI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=EV8bB+ZX; 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="EV8bB+ZX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D52FFC2BCAF; Mon, 13 Apr 2026 16:08:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1776096506; bh=VUCfXGotR8gRq17l8mszLnBbBhLK/pAwUwELVgP5YQI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EV8bB+ZXcCA63SP1RSkCnQoang3lOZpscNnG5W2yEpLcBlmtOcWQisVkUSlddx1Ix qJB9rPCdcu8tQitLthozykrutkNOeWJcCPQ431l8ac1i+/N2TuiPUNHbjOK++iqH+r 1GQUoVue7Es+s6D6i0R3r1eIsk1RPapcwWieqhZI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Pengpeng Hou , Paolo Abeni Subject: [PATCH 6.18 36/83] nfc: pn533: allocate rx skb before consuming bytes Date: Mon, 13 Apr 2026 18:00:04 +0200 Message-ID: <20260413155732.366542646@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260413155731.019638460@linuxfoundation.org> References: <20260413155731.019638460@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 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 timer_delete(&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;