From nobody Sun Jun 21 17:18:19 2026 Received: from cstnet.cn (smtp21.cstnet.cn [159.226.251.21]) (using TLSv1.2 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 841A230C371; Thu, 2 Apr 2026 04:21:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=159.226.251.21 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775103721; cv=none; b=HTPuPejwLPcNWM6sZ309AgHKxdo+/3fFsdQw3gjQEPg1WtfmhTVAR2Zc8NkGvJxkTLR0WQP9My9dVzpZIVIKmURbJeHd7p5QQf7nMuQc+ZQcps5ydfPAO2aeBklvs/Hj9nTNqCQ/mxKEfYM1CIqxY7JVn4jLWHCUSp4xeJdTKnM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775103721; c=relaxed/simple; bh=PqEcBA2A5b9cJkiPpiRNEoBquqciKCg2vR5h3FlNsug=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=M8/v+WTL56i8VzSK8D3DwPhIbJ1jHT0jB5PkUFlRl0IekFa0OnQSCMejRfFm5+V5d5sjdRd10a32JcrI+SFi7MXxgkOm5ir8HsCH+Kj1JbMsaHQkj2jbG34RP5V891kmmItyP4KaDbmunYPkn97Zd8fNVC0TLefkiDSn12ytHo0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=iscas.ac.cn; spf=pass smtp.mailfrom=iscas.ac.cn; arc=none smtp.client-ip=159.226.251.21 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=iscas.ac.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=iscas.ac.cn Received: from localhost.localdomain (unknown [111.196.245.197]) by APP-01 (Coremail) with SMTP id qwCowADXfWnc7s1pfEzwCw--.40389S2; Thu, 02 Apr 2026 12:21:48 +0800 (CST) From: Pengpeng Hou To: Krzysztof Kozlowski Cc: Bongsu Jeon , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, pengpeng@iscas.ac.cn, stable@vger.kernel.org Subject: [PATCH] nfc: s3fwrn5: allocate rx skb before consuming bytes Date: Thu, 2 Apr 2026 12:21:48 +0800 Message-ID: <20260402042148.65236-1-pengpeng@iscas.ac.cn> X-Mailer: git-send-email 2.50.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: qwCowADXfWnc7s1pfEzwCw--.40389S2 X-Coremail-Antispam: 1UD129KBjvJXoW7CF1rJrW3Aw1fJr13Ar4fKrg_yoW8AF4UpF 45J3Wjqry8tr43J3WDCw18WFy5Ca4fJFW5Gry5Kw48ZrWfJrZ5JayI9Fyj9r4rXr4kWFW3 AF4xJa1rC3W0vrUanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUkG14x267AKxVWUJVW8JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26ryj6F1UM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r4j 6F4UM28EF7xvwVC2z280aVAFwI0_Cr1j6rxdM28EF7xvwVC2z280aVCY1x0267AKxVW0oV Cq3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0 I7IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFVCjc4AY6r1j6r 4UM4x0Y48IcxkI7VAKI48JM4x0x7Aq67IIx4CEVc8vx2IErcIFxwCY1x0262kKe7AKxVWU AVWUtwCF04k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14 v26r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_JF0_Jw1lIxkG c2Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxVAFwI 0_Jr0_Gr1lIxAIcVCF04k26cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r1j6r4U MIIF0xvEx4A2jsIEc7CjxVAFwI0_Gr0_Gr1UYxBIdaVFxhVjvjDU0xZFpf9x0JUSNtxUUU UU= X-CM-SenderInfo: pshqw1xhqjqxpvfd2hldfou0/ Content-Type: text/plain; charset="utf-8" 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") Cc: stable@vger.kernel.org Signed-off-by: Pengpeng Hou --- 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 9c09c10c2a46..4ee481bd7e96 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 *s= erdev, size_t i; =20 for (i =3D 0; i < count; i++) { + if (!phy->recv_skb) { + phy->recv_skb =3D alloc_skb(NCI_SKB_BUFF_LEN, GFP_KERNEL); + if (!phy->recv_skb) + return i; + } + skb_put_u8(phy->recv_skb, *data++); =20 if (phy->recv_skb->len < S3FWRN82_NCI_HEADER) @@ -69,9 +75,7 @@ static size_t s3fwrn82_uart_read(struct serdev_device *se= rdev, =20 s3fwrn5_recv_frame(phy->common.ndev, phy->recv_skb, phy->common.mode); - phy->recv_skb =3D alloc_skb(NCI_SKB_BUFF_LEN, GFP_KERNEL); - if (!phy->recv_skb) - return 0; + phy->recv_skb =3D NULL; } =20 return i; --=20 2.50.1 (Apple Git-155)