From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm2-f12.google.com (mail-wm2-f12.google.com [74.125.225.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 37C0A3E2AD1 for ; Sun, 4 Oct 2026 22:00:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.225.140 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791151207; cv=none; b=ZZNCFRXLbelV6P9mhyk5fIQJog3q3YE3EVJ9feFnk1HJd9PoE+tH9vQNfdqbr/zHsfYA2oRmiA25v0AGcQ7nmf25/ccwXcTPHqDhMvo2ICWrqDTifnbxvBobXfbixLXGQpa7I/YvEps07xltIJeIuJ7XLgWUbAIjRCxIAPEbr58= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791151207; c=relaxed/simple; bh=A49zyjjnqqb50pG4MqWzNRlRKAi9xTHYpw2ixK1+k84=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type; b=gRlBNnPKTU0NFIw6PEB4w3ZsbW1yu4txfjfajeDNtp11Nnq7DVdSCz+D7ta+Jj1suwGDKnKI6pOrdYPtYAmDRfNtAxx4/WhoOtF0rIXI9bgrw4eNiuoUHegj5gvuYek4gHZSQnv061fcjneU/gPMzCkWZdwEpUqn7e49BpxH1Bc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=RsNSgBPe; arc=none smtp.client-ip=74.125.225.140 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="RsNSgBPe" Received: by mail-wm2-f12.google.com with SMTP id 5b1f17b1804b1-49b912d8239so10328235e9.0 for ; Sun, 04 Oct 2026 15:00:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1791151204; x=1791756004; darn=vger.kernel.org; h=content-transfer-encoding:content-type:mime-version:message-id:date :subject:cc:to:from:from:to:cc:subject:date:message-id:reply-to :content-type; bh=v9ZMcU4NSbtXZ2T+rqlz7vA0bY14DXoiCQpMM48epr0=; b=RsNSgBPeuAwryu6cQEQFTvpMvhmclslYU+UDPuOLsR94lwv0GFEFC21qRMaIunzVd/ wKJK0CBl4/WbBWpmfJuE1anC1jtMuzHSeXUmjXmJv9fgOsAwbqgzHS5fUOLCzgzw5Gfd v6Wxoy7XmmGDdfvShzCLKflCAixNZjnHjHhlZXjWVhJgVzF3C1i+mtWUYNYujkd1UQxI 3Pbmpm6t5klfqL1cpYFMQ2iKK24I0lPH3wXukZfuNHYTJ5tpzCa/ioYWQMpeudL7MeWM l4Iz0dnV1Akbnts1PEIhpH9SxZZb3LmxCn72dWBbFy2jzf0K0ZNABDLCO1gz60AG4Bak q3Ow== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1791151204; x=1791756004; h=content-transfer-encoding:content-type:mime-version:message-id:date :subject:cc:to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject :date:message-id:reply-to:content-type; bh=v9ZMcU4NSbtXZ2T+rqlz7vA0bY14DXoiCQpMM48epr0=; b=R52iOyJ/rVi3Dq68Q7cdXj6dK06QNfougDqsyvV09d8/p+8P0Hc4SdMtQgtvfCanKt VU4D/LTs7nBJB/kFJRNK2rLiRFfy2mQEc3bK59AOyaHQ4REx2jDc8cNmE2k6YbhSkVP+ 32DS/k5io8motx5GRGSSIJ+PJqfx9CAc7s/qiQPdkMEZaLVs+QGg2A+d5S1N7drdv8NP xFiX4EbB3j/8ossZ1boAVBIx17cvbf8c/2vw0ED5AzuA/YLY0J0ARhinuWLkRmzQ0h9F 6RO9h79A/AxTIi1h1o47wibeVQW5Qm4psRfMF+yPsqOEiI+uFzPNewnJY+3F+/iBq4DK y7iw== X-Forwarded-Encrypted: i=1; AKwUvByHl5jQsU40wh/10YA1aKCc7qswwZnYpTMk7ygFu6Lk/tTXRAx0MO05qYgT5/13q4fA2qgkIZOpi1I=@vger.kernel.org X-Gm-Message-State: AFuF++lSG32k5g052Lj5azk96d/8lEg7YhrywbduyHXWUI1YyZADLRyo /zIMNGIVMGqPEpcohtpCbThjTdkmQi0XOGwnLjlpOcoMMIJnZN5sTluM X-Gm-Gg: AYBFou3u471P1By+fo/yAepX0iMe7qyK9zj9MCieggYEPwrrgU89NiEXpYaERFVZZW+ MDBH6SV1xQc8kVA3mgtaFYUkT3st9F5IHpBnzlYsk75MLtypiXEfTXBEedeZ90Q8yiPoMmRUpk8 08a4uqtZl5vImyjHPnOTcAP+Y2n5FVhwtz9W2QigEPdCqFWB8LX3QsjG/CrGTgNMJCneb0SqnsE LQyx2xWbS3rxmgJS58LWh49LHEFqwLByDvY1msZ0ZBIVdTUJLlZLcz4XV1TGRZq2y/c7S4mMT3Y spqts1z7FXgZN05lxVZ5Hde8+OE8bKDxGZhtxAd6EaB04KqGkVsS1c0ddsEJXXQLj+2f1/iIuD/ rTW5EtBLzxtZ/IKEfwvnOOrmxRpBsBIhTi0tC4ADXp79luj/z7lyeJl+/gh8TeIGgFlJMU9sRiI v/QvEfAjM6Mkpl7BfBZkPnupYrawcaQNUlgAB/waUkCcongQUpdCFxwF150IHSIMDD+0R90ADuj ylKjsY= X-Received: by 2002:a05:600c:3b1d:b0:4a1:7033:5b55 with SMTP id 5b1f17b1804b1-4a170335d02mr45106945e9.21.1791151204108; Sun, 04 Oct 2026 15:00:04 -0700 (PDT) Received: from metepc ([46.197.185.71]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4a0a6e894a4sm256671015e9.5.2026.10.04.15.00.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 04 Oct 2026 15:00:03 -0700 (PDT) From: =?UTF-8?q?=C3=96mer=20Mete=20Kaya?= To: netdev@vger.kernel.org Cc: oneukum@suse.com, andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, david.laight.linux@gmail.com, syzbot+04cd90bb99c6ef81a65d@syzkaller.appspotmail.com, =?UTF-8?q?=C3=96mer=20Mete=20Kaya?= Subject: [PATCH net v6] usbnet: fix smp_processor_id() use in preemptible context Date: Mon, 5 Oct 2026 00:59:25 +0300 Message-ID: <20261004215937.302247-1-omermetekaya0@gmail.com> X-Mailer: git-send-email 2.55.0 Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit tx_complete() calls this_cpu_ptr() before disabling preemption, which triggers a BUG when running with CONFIG_DEBUG_PREEMPT: BUG: using smp_processor_id() in preemptible code in tx_complete Fix by using get_cpu_ptr()/put_cpu_ptr() which disable preemption and return the per-CPU pointer atomically. The usbnet_skb_return() hunk is a hardening change: that path runs in softirq context so no warning fires there, but the same fix is applied for consistency. Fixes: ed194d136769 ("usb: core: remove local_irq_save() around ->complete() handler") Suggested-by: David Laight Reported-by: syzbot+04cd90bb99c6ef81a65d@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=04cd90bb99c6ef81a65d Signed-off-by: Ömer Mete Kaya --- v6: Fix commit message and Fixes tag as pointed out by Sashiko: - BUG is in tx_complete(), not usbnet_skb_return() - usbnet_skb_return() hunk is hardening, not a fix - CONFIG_DEBUG_PREEMPT, not PREEMPT_FULL - Fixes tag updated to ed194d136769 --- drivers/net/usb/usbnet.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c index a19ecf718f36..84f97f448b2d 100644 --- a/drivers/net/usb/usbnet.c +++ b/drivers/net/usb/usbnet.c @@ -325,7 +325,7 @@ static void __usbnet_status_stop_force(struct usbnet *dev) */ void usbnet_skb_return(struct usbnet *dev, struct sk_buff *skb) { - struct pcpu_sw_netstats *stats64 = this_cpu_ptr(dev->net->tstats); + struct pcpu_sw_netstats *stats64; unsigned long flags; int status; @@ -338,10 +338,12 @@ void usbnet_skb_return(struct usbnet *dev, struct sk_buff *skb) if (skb->protocol == 0) skb->protocol = eth_type_trans(skb, dev->net); + stats64 = get_cpu_ptr(dev->net->tstats); flags = u64_stats_update_begin_irqsave(&stats64->syncp); u64_stats_inc(&stats64->rx_packets); u64_stats_add(&stats64->rx_bytes, skb->len); u64_stats_update_end_irqrestore(&stats64->syncp, flags); + put_cpu_ptr(dev->net->tstats); netif_dbg(dev, rx_status, dev->net, "< rx, len %zu, type 0x%x\n", skb->len + sizeof(struct ethhdr), skb->protocol); @@ -1298,13 +1300,15 @@ static void tx_complete(struct urb *urb) struct usbnet *dev = entry->dev; if (urb->status == 0) { - struct pcpu_sw_netstats *stats64 = this_cpu_ptr(dev->net->tstats); + struct pcpu_sw_netstats *stats64; unsigned long flags; + stats64 = get_cpu_ptr(dev->net->tstats); flags = u64_stats_update_begin_irqsave(&stats64->syncp); u64_stats_add(&stats64->tx_packets, entry->packets); u64_stats_add(&stats64->tx_bytes, entry->length); u64_stats_update_end_irqrestore(&stats64->syncp, flags); + put_cpu_ptr(dev->net->tstats); } else { dev->net->stats.tx_errors++; -- 2.55.0