From nobody Sat Apr 4 00:07:08 2026 Received: from mail-lf1-f50.google.com (mail-lf1-f50.google.com [209.85.167.50]) (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 133BE30FC34 for ; Sun, 22 Mar 2026 07:59:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.167.50 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774166396; cv=none; b=QmLzTzvGvfYcPHSm+tEfbHEhzHVBB1Vflbiw0pFNncbjPx2j/6txy9GQbFaV00CL0+l1e1K6v6SGgvWDdWpNASjnNxVqp7wVmjhISIJsCtoDJZ/bGahBQDbrTqvxGxKwvlVdrA7XLffGnhEpqWWFjI68MpK6uYQOWVx6X9nWQeI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774166396; c=relaxed/simple; bh=BD7bms+Hzvy8wuKEAuDav0KFq5A+rpA5hIlA0ooPYCk=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=KcpXdSFjFQTrLYIjfJu5PnTAQbi0G1qmS14JxTnetmzihQL6sVaYD5yq2WVm82xA4COwZrtbZBjtaO6ZOodm4uZzj88OMk3PGZuNXlUL42VHfX2M7i7q2hO0jwotnzdQPvk5/TzZCju0nLV2Xti9vwTQvdzMSDwh2WmzH3XEANk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.com; spf=pass smtp.mailfrom=gmail.com; arc=none smtp.client-ip=209.85.167.50 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Received: by mail-lf1-f50.google.com with SMTP id 2adb3069b0e04-5a281b091c2so3261806e87.0 for ; Sun, 22 Mar 2026 00:59:53 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1774166392; x=1774771192; h=content-transfer-encoding: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; bh=GwUa87/6nNV3BAxMOJ2odF4NoyI5ya2/Ap5luWyyXEk=; b=nASxnqFO0J7a5FqdMVvpFp4THDdI77T4DSfCwijMnG1lbZEDOaTKRiiIbh01kA5sJS 7UroY8dHX0h+kRRGbtth5ddmTRrjHJv2pMuE59ZfTm3WSlbqRBi5J1SOpXwACfCXaWXh 9ozOCB1xBZ/Lr/8frKIxhnx9cVq58SgJDKNDJ7Yz8n6aMniFeI6X4nH5u22TWpIA4dLp fpRtMWd0PnHw74/eXcvzeV5oISlb2vzxYEvVVS4p5Z/wcO/JEolxLPTdD7paGJHhBfY7 7cBbjViSL2w+1xjr+mMaQ2dXe84hKUuAVtsZV/I9JjE06OGoQDUHmssidNFAx4nTpESE R9MA== X-Forwarded-Encrypted: i=1; AJvYcCWGzahXG7xsX3V9OBEyhX6seGUKRHQfNrqUZWKAlxqTyN+89OymqImYlDgB491frGMFhFpwFblujw53YBU=@vger.kernel.org X-Gm-Message-State: AOJu0Ywp+mM+mCk/tNt4LKLw1llvh6Imi54sGKEpOoEm7Kv3kSnGMuql Zrk5G1MtPiYJga9QHgdvGY8T928k6QRiRAoOmdyWdCJLiVU6sz0Awydo X-Gm-Gg: ATEYQzxiGpgbrYRgqEJvmICeUoNSsuWb0Se38DjfLo29x7sFRAvdGHZ+lWDnARuq3Qa HamMkQdr4LUKY2ZMdQcB1BK2GAAWP5VRF7Z9yiNRhwFXr+1F1UAszz8JjEIqM5jCd0E2n26YeNV btpm2kHffb28AqWty8EkwqOMY0Q8sP9wXJiJG16SefnG7TYT1dZo8JPjWn/defY1Gvv09Qb8CR0 7ywF64xWsvSywj1Xh/XhZt5BJ5FLcrzmLZCJArgj8928841QvoLGMG10wRkLTl6Ya2uawVs9qy5 V0zRQYo8VA5ERHNcwsu5dv2ndcWYWfTT5pvR8qnjFgzSHCcmw/MBAye1EMjfZkre8xdnbnYMC8B Lg8YSA9elhRtTeuFHRWBJ/NO/GgCWGDolqhWBMiRUdZXmf/jvWYrYEuWYDAT+Ak+PzoTKPes9tY P9Z8JhwMOGAyyvTejkuu14 X-Received: by 2002:a05:6512:224e:b0:5a1:3207:694c with SMTP id 2adb3069b0e04-5a285b80c25mr3534878e87.29.1774166391898; Sun, 22 Mar 2026 00:59:51 -0700 (PDT) Received: from hackbase ([213.87.137.203]) by smtp.gmail.com with ESMTPSA id 2adb3069b0e04-5a285305e31sm1591206e87.64.2026.03.22.00.59.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 22 Mar 2026 00:59:51 -0700 (PDT) From: Alexander Popov To: Andrew Lunn , Jakub Kicinski , David Miller , Eric Dumazet , Paolo Abeni , Simon Horman , Maxime Chevallier , Michal Kubecek , Gal Pressman , Kory Maincent , Oleksij Rempel , Ido Schimmel , Heiner Kallweit , Greg KH , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Alexander Popov Cc: security@kernel.org, notify@kernel.org Subject: [PATCH] ethtool: don't touch the parent device of a net device being unregistered Date: Sun, 22 Mar 2026 10:59:15 +0300 Message-ID: <20260322075917.254874-1-alex.popov@linux.com> X-Mailer: git-send-email 2.53.0 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 Content-Type: text/plain; charset="utf-8" The ethtool operations may be performed on a net device that is currently being unregistered. This is also described in the commit dde91ccfa25fd58f ("ethtool: do not perform operations on net devices being unregistered"). Moreover, such a device may have a parent that has already been freed. Let's check the net device reg_state in ethnl_ops_begin() before calling pm_runtime_get_sync() for its parent device to avoid use-after-free like this: =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D BUG: KASAN: slab-use-after-free in __pm_runtime_resume+0xe2/0xf0 Read of size 2 at addr ffff88810cfc46f8 by task pm/606 Call Trace: dump_stack_lvl+0x4d/0x70 print_report+0x170/0x4f3 ? __pfx__raw_spin_lock_irqsave+0x10/0x10 kasan_report+0xda/0x110 ? __pm_runtime_resume+0xe2/0xf0 ? __pm_runtime_resume+0xe2/0xf0 __pm_runtime_resume+0xe2/0xf0 ethnl_ops_begin+0x49/0x270 ethnl_set_features+0x23c/0xab0 ? __pfx_ethnl_set_features+0x10/0x10 ? kvm_sched_clock_read+0x11/0x20 ? local_clock_noinstr+0xf/0xf0 ? local_clock+0x10/0x30 ? kasan_save_track+0x25/0x60 ? __kasan_kmalloc+0x7f/0x90 ? genl_family_rcv_msg_attrs_parse.isra.0+0x150/0x2c0 genl_family_rcv_msg_doit+0x1e7/0x2c0 ? __pfx_genl_family_rcv_msg_doit+0x10/0x10 ? __pfx_cred_has_capability.isra.0+0x10/0x10 ? stack_trace_save+0x8e/0xc0 genl_rcv_msg+0x411/0x660 ? __pfx_genl_rcv_msg+0x10/0x10 ? __pfx_ethnl_set_features+0x10/0x10 netlink_rcv_skb+0x121/0x380 ? __pfx_genl_rcv_msg+0x10/0x10 ? __pfx_netlink_rcv_skb+0x10/0x10 ? __pfx_down_read+0x10/0x10 genl_rcv+0x23/0x30 netlink_unicast+0x60f/0x830 ? __pfx_netlink_unicast+0x10/0x10 ? __pfx___alloc_skb+0x10/0x10 netlink_sendmsg+0x6ea/0xbc0 ? __pfx_netlink_sendmsg+0x10/0x10 ? __futex_queue+0x10b/0x1f0 ____sys_sendmsg+0x7a2/0x950 ? copy_msghdr_from_user+0x26b/0x430 ? __pfx_____sys_sendmsg+0x10/0x10 ? __pfx_copy_msghdr_from_user+0x10/0x10 ___sys_sendmsg+0xf8/0x180 ? __pfx____sys_sendmsg+0x10/0x10 ? __pfx_futex_wait+0x10/0x10 ? fdget+0x2e4/0x4a0 __sys_sendmsg+0x11f/0x1c0 ? __pfx___sys_sendmsg+0x10/0x10 do_syscall_64+0xe2/0x570 ? exc_page_fault+0x66/0xb0 entry_SYSCALL_64_after_hwframe+0x77/0x7f Fixes: d43c65b05b848e0b ("ethtool: runtime-resume netdev parent in ethnl_op= s_begin") Cc: stable@vger.kernel.org Signed-off-by: Alexander Popov --- net/ethtool/netlink.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/net/ethtool/netlink.c b/net/ethtool/netlink.c index 6e5f0f4f815a..1cdedd1af24d 100644 --- a/net/ethtool/netlink.c +++ b/net/ethtool/netlink.c @@ -94,17 +94,16 @@ int ethnl_ops_begin(struct net_device *dev) if (!dev) return -ENODEV; =20 - if (dev->dev.parent) - pm_runtime_get_sync(dev->dev.parent); - netdev_ops_assert_locked(dev); =20 if (!netif_device_present(dev) || dev->reg_state >=3D NETREG_UNREGISTERING) { - ret =3D -ENODEV; - goto err; + return -ENODEV; } =20 + if (dev->dev.parent) + pm_runtime_get_sync(dev->dev.parent); + if (dev->ethtool_ops->begin) { ret =3D dev->ethtool_ops->begin(dev); if (ret) --=20 2.53.0