From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f197.google.com (mail-pg1-f197.google.com [209.85.215.197]) (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 F2BC836194A for ; Tue, 11 Aug 2026 19:54:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.197 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786478048; cv=none; b=U/lweVGWLrjsrBN/MBljNfBcBqpAq+7bIthPL6toRDWyWMIo5sIeleslH9Do0Me5uAbJUVNSgqINjp2puta3qMDZUwlut6UB4fjEkfrAdW0E/1RFW3J8+ZgqJf0RNgCTJk+5dDuYXdmSoKSsGV9oBRe4x35dcvyfMQ1lmPAb1f8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786478048; c=relaxed/simple; bh=uv5bJTiywtvIjoIAxnUMtZ+nXypc0LrMQnCrdgTaIFU=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=Pxc5EIKqpAU0dGZ5dimxee1C+PjRqXhKot4sYlTdslglIdCWVjE5TVWVYlsvyYXh1giCydNY9Za61GoRF4m2faTs9WgAdC10WPSnE1x209/Wys455xsKUbRmbcfmd2xOiTPo9rjpW6A1kHUUNPFAieNS9T5VsxX8UEEakCjKzpk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--almasrymina.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=YVVdd7kr; arc=none smtp.client-ip=209.85.215.197 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--almasrymina.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="YVVdd7kr" Received: by mail-pg1-f197.google.com with SMTP id 41be03b00d2f7-cbedf42f199so161553a12.2 for ; Tue, 11 Aug 2026 12:54:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1786478046; x=1787082846; darn=vger.kernel.org; h=content-type:cc:to:from:subject:message-id:mime-version:date:from :to:cc:subject:date:message-id:reply-to:content-type; bh=JgAFNW26nQ+7bGg4Sj1IWeLiDHNMoP2ck4YKWQasXjk=; b=YVVdd7krUV5hhI0dcvHJdVWj5mJoTp9ZKnE9cat0P2iYdXKLhEsGe7SvL1LEJW7xBV e/l66YpZGDBp7dQYRX1QDB7EUBpVZn7SoTOkQeG0oQzpGF5A2HkJm7sV3O84REuPW/dv Gj54zqvvOMx0cTudsKIMtKA5HgDpBHL9Pk4ctvg2THPeREPducxZX16bEEISITabqR9v 52CNQHUqenQEmoZXjIsBUww83Km1cpsNhwfuoGljUZ+m8bJ11SCT8VA5guoXddMYya7H kU9yH+vpcFF1/zPaGXzvEPU68KXIzO1pmTPDGSIdsnzWj8qcr7rMCmtdoW7oCZRbHpTH Jsrg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1786478046; x=1787082846; h=content-type:cc:to:from:subject:message-id:mime-version:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=JgAFNW26nQ+7bGg4Sj1IWeLiDHNMoP2ck4YKWQasXjk=; b=ZxXE+eu2boTd7GHBafVzcJWaH2HJZzin4xBOmCelpAS21imnynpXw7kJi5sSWm25Uv BulHw7bQw1Jkcd+bZr+eoVQkkYiHjuu2KAY4RToD4p83brS3Ja1DAZ7mFXq7iOi5s5Uh PNwtzvFrRtSxEsVSSdzQ7oYZcrhOBDr402TWkbJJP9SkJtDBIdeVTLXbzDwpXCSHCjv+ y3qIPmz9TGA9QTjqTTju32Ga8bSbum5ISDO4CCVuTVob37ZMSb4QyF4jLt4CpwDZOK6L bgtRasUXKm+ioJxprQwc6RNEoub0CajQ9PV/aIf9Cwon4oubX+fEp4ZT59sLvGxiFQeX RKIA== X-Forwarded-Encrypted: i=1; AHgh+RoOuY70CDu1gbGbr8JJ7rgST+oplKvWKIzrUQtXHlChsYGUPNl0PUWqKJ2NGid7lQ3QR/A2JXg=@vger.kernel.org X-Gm-Message-State: AOJu0Yz0SeMwkdzHAgnWA4yfI/5Lnu2mHJPm/hdRYVmdDxKuT4C/jrvM E84O0ns4bFZgq7xmW4VHPp4Wdbi0/UuSMOpMqBrqHa8XC6U3i8dtdvbhUjeVeViaqx2exK6QzNq nojS3AVeHRf/oy0ljpSlnUYx0LA== X-Received: from dybpd4.prod.google.com ([2002:a05:7301:4544:b0:30f:3dee:fdfe]) (user=almasrymina job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a20:be8f:b0:3c4:3321:4fe8 with SMTP id adf61e73a8af0-3cc2b87d093mr8282193637.14.1786478046006; Tue, 11 Aug 2026 12:54:06 -0700 (PDT) Date: Tue, 11 Aug 2026 19:53:38 +0000 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Mailer: git-send-email 2.55.0.679.g6767b8d81c-goog Message-ID: <20260811195405.3979177-1-almasrymina@google.com> Subject: [PATCH net v3 1/2] net: core: propagate unreadable flag in skb_zerocopy From: Mina Almasry To: Jakub Kicinski , Willem de Bruijn , Eric Dumazet , Mina Almasry , Kaiyuan Zhang , Stanislav Fomichev , Paolo Abeni , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, dev@openvswitch.org Cc: "David S. Miller" , Simon Horman , Neal Cardwell , Kuniyuki Iwashima , Aaron Conole , Eelco Chaudron , Ilya Maximets , Jason Xing , Pavel Begunkov , Bobby Eshleman , Florian Westphal Content-Type: text/plain; charset="UTF-8" skb_zerocopy() fails to propagate the unreadable flag when copying devmem fragments, causing target skbs to appear as readable memory. This patch fixes the flag propagation. Additionally, it returns -EFAULT if standard payload is mixed with unreadable devmem fragments during extraction, and returns -EFAULT in openvswitch queue_userspace_packet(). Fixes: 65249feb6b3d ("net: add support for skbs with unreadable frags") Cc: Pavel Begunkov Cc: Stanislav Fomichev Cc: Bobby Eshleman Cc: Florian Westphal Cc: Aaron Conole Cc: Eelco Chaudron Cc: Ilya Maximets Cc: Willem de Bruijn Reviewed-by: Pavel Begunkov Signed-off-by: Mina Almasry --- net/core/skbuff.c | 13 ++++++++++++- net/openvswitch/datapath.c | 3 +++ 2 files changed, 15 insertions(+), 1 deletion(-) diff --git a/net/core/skbuff.c b/net/core/skbuff.c index ba3dbac80fb49..d21af68156950 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -3870,7 +3870,8 @@ EXPORT_SYMBOL_GPL(skb_zerocopy_headlen); * Return value: * 0: everything is OK * -ENOMEM: couldn't orphan frags of @from due to lack of memory - * -EFAULT: skb_copy_bits() found some problem with skb geometry + * -EFAULT: skb_copy_bits() found some problem with skb geometry, or readable head + * payload would be mixed with unreadable frags. */ int skb_zerocopy(struct sk_buff *to, struct sk_buff *from, int len, int hlen) @@ -3905,10 +3906,17 @@ skb_zerocopy(struct sk_buff *to, struct sk_buff *from, int len, int hlen) } } + if (!skb_frags_readable(from) && j > 0 && len) { + put_page(virt_to_head_page(from->head)); + return -EFAULT; + } + skb_len_add(to, len + plen); if (unlikely(skb_orphan_frags(from, GFP_ATOMIC))) { skb_tx_error(from); + if (j > 0) + put_page(virt_to_head_page(from->head)); return -ENOMEM; } skb_zerocopy_clone(to, from, GFP_ATOMIC); @@ -3928,6 +3936,9 @@ skb_zerocopy(struct sk_buff *to, struct sk_buff *from, int len, int hlen) } skb_shinfo(to)->nr_frags = j; + if (i > 0 && from->unreadable) + to->unreadable = 1; + return 0; } EXPORT_SYMBOL_GPL(skb_zerocopy); diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c index ae69b2cabab9e..482893a5f67dc 100644 --- a/net/openvswitch/datapath.c +++ b/net/openvswitch/datapath.c @@ -467,6 +467,9 @@ static int queue_userspace_packet(struct datapath *dp, struct sk_buff *skb, if (!dp_ifindex) return -ENODEV; + if (!skb_frags_readable(skb)) + return -EFAULT; + if (skb_vlan_tag_present(skb)) { nskb = skb_clone(skb, GFP_ATOMIC); if (!nskb) base-commit: cba9ccb47e9fa4cc77692fb896cc5ab57a667882 -- 2.55.0.679.g6767b8d81c-goog