From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 85AF453A3A5; Wed, 23 Sep 2026 14:47:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790174850; cv=none; b=sTphWipwgnCk6oTAKFXvGNoSCmIHlEYMCtl0No4FoNwBnzcyLfhuWoqT588QDK9r+rD3yA9Iq5x+V3jBxrXbqHcflBUFeKVF++EdkL8n2gktgqqkUOAgo3jFOxKr7+7xMStvXHrSdS8LqlqhuJm5MtwxwI0djkcDc1/I0JPbg9M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790174850; c=relaxed/simple; bh=XJ/hOmX6mXjOdXpmZbrg7Ci2RcofFimxYAHx+YUptIo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ASCDqVmhRt3n0olF0B3wA3pLgce06zy01ToMdrCzF3T3rZEmtyT2TVuWm4QDdEPEKmu2RXSgr5IS1bmuWvp4Fjgr8XBVRbTGwjVfivA3uduo2tog0gUzxSLrZvajFQKzjwOTU3n6tuPvYpg1VbOOCPFS+B9oYZB6WZb6elyGpjc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=lToq00Zs; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="lToq00Zs" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C0BCD1F000FF; Wed, 23 Sep 2026 14:47:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790174848; bh=u+MPBWmyR3f6tJ6at2K/xAWOKeRmKRGBeQyLU+C/SgI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=lToq00ZsB5Hjv68dH/ekZhPXkwJJLNbFhj5LjDUJC5st8M2tfSk+5ylm+N5hDZsvS vACu/uD7i5GeUsIlZQz26IxY+VBtUPD8XjdlZja0xHSb6zR4DtSvdkio0DLZXMyhV5 /SFnAdc9uBtsvdscIGV6d7oqsO6uO1d9OznzaD+M= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Chunfeng Song , FUJITA Tomonori , Jakub Kicinski Subject: [PATCH 6.18 210/398] rust: net: phy: fix off-by-one bit positions in device status accessors Date: Wed, 23 Sep 2026 16:04:44 +0200 Message-ID: <20260923140648.864493062@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260923140643.441954610@linuxfoundation.org> References: <20260923140643.441954610@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: Chunfeng Song commit 6fb0a9d9071f1ff0cc5cfc0782302d9c90d642cb upstream. The hand-written bitfield offsets in is_link_up(), is_autoneg_enabled() and is_autoneg_completed() were correct when the abstraction was merged: at that time autoneg, link, and autoneg_complete were at bits 13, 14, and 15 of struct phy_device's first bitfield unit. Commit 2796ff1e3dca ("net: phy: add flag is_genphy_driven to struct phy_device") later inserted is_genphy_driven just before autoneg, shifting the three fields up by one, so the accessors now read: is_link_up() reads bit 14 = autoneg is_autoneg_enabled() reads bit 13 = is_genphy_driven is_autoneg_completed() reads bit 15 = link The official ax88796b Rust driver uses all three accessors in its read_status() implementation, so it inherits the bug. phy_attach_direct() sets is_genphy_driven only when it falls back to the generic driver, and ax88796b has a real driver, so is_genphy_driven stays 0. The broken is_autoneg_enabled() therefore reads bit 13 as 0, compares it against AUTONEG_ENABLE (1), and always returns false, so read_status() never reaches the resolve_aneg_linkmode() call. The ordinary bindgen accessors take &self. Calling them through (*phydev).link() would create a shared reference to the complete bindings::phy_device, which is not appropriate for an object wrapped in Opaque. Use the bindgen-generated raw accessors (link_raw(), autoneg_raw(), and autoneg_complete_raw()) instead. They retain the bit positions and endianness handling generated from the C layout without creating a Rust reference to the complete phy_device. Drop the hand-written numbers together with the TODO comment that marked them as a stopgap. The raw accessors are only emitted by bindgen 0.71 and later, and were added at the Rust-for-Linux project's request, so this fix can only be backported to stable branches whose minimum bindgen version is at least that, hence the scope on the Cc: stable line below. Found by a static equivalence audit (C2RustDrv, a C-to-Rust driver migration tool) that compares hand-written bitfield offsets against the bindgen layout of struct phy_device. Verified by building the bindings and checking the generated accessors; no runtime testing was possible without PHY hardware. Fixes: 2796ff1e3dca ("net: phy: add flag is_genphy_driven to struct phy_device") Cc: stable@vger.kernel.org # Only 7.1.y and later (requires bindgen's raw pointer accessors). Link: https://github.com/rust-lang/rust-bindgen/issues/2674 Signed-off-by: Chunfeng Song Reviewed-by: FUJITA Tomonori Link: https://patch.msgid.link/20260910055110.167110-1-springbreeze@stu.pku.edu.cn Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- rust/kernel/net/phy.rs | 38 ++++++++++++++++++-------------------- 1 file changed, 18 insertions(+), 20 deletions(-) diff --git a/rust/kernel/net/phy.rs b/rust/kernel/net/phy.rs index 956cda573ddb..c4e7b1d6c6f4 100644 --- a/rust/kernel/net/phy.rs +++ b/rust/kernel/net/phy.rs @@ -123,39 +123,37 @@ pub fn state(&self) -> DeviceState { /// Gets the current link state. /// /// It returns true if the link is up. + #[inline] pub fn is_link_up(&self) -> bool { - const LINK_IS_UP: u64 = 1; - // TODO: the code to access to the bit field will be replaced with automatically - // generated code by bindgen when it becomes possible. - // SAFETY: The struct invariant ensures that we may access - // this field without additional synchronization. - let bit_field = unsafe { &(*self.0.get())._bitfield_1 }; - bit_field.get(14, 1) == LINK_IS_UP + let phydev = self.0.get().cast_const(); + // SAFETY: By the type invariant of `Device`, `phydev` points to a valid + // `struct phy_device`, and there is no concurrent write to this field. + let link = unsafe { bindings::phy_device::link_raw(phydev) }; + link == 1 } /// Gets the current auto-negotiation configuration. /// /// It returns true if auto-negotiation is enabled. + #[inline] pub fn is_autoneg_enabled(&self) -> bool { - // TODO: the code to access to the bit field will be replaced with automatically - // generated code by bindgen when it becomes possible. - // SAFETY: The struct invariant ensures that we may access - // this field without additional synchronization. - let bit_field = unsafe { &(*self.0.get())._bitfield_1 }; - bit_field.get(13, 1) == u64::from(bindings::AUTONEG_ENABLE) + let phydev = self.0.get().cast_const(); + // SAFETY: By the type invariant of `Device`, `phydev` points to a valid + // `struct phy_device`, and there is no concurrent write to this field. + let autoneg = unsafe { bindings::phy_device::autoneg_raw(phydev) }; + autoneg == bindings::AUTONEG_ENABLE } /// Gets the current auto-negotiation state. /// /// It returns true if auto-negotiation is completed. + #[inline] pub fn is_autoneg_completed(&self) -> bool { - const AUTONEG_COMPLETED: u64 = 1; - // TODO: the code to access to the bit field will be replaced with automatically - // generated code by bindgen when it becomes possible. - // SAFETY: The struct invariant ensures that we may access - // this field without additional synchronization. - let bit_field = unsafe { &(*self.0.get())._bitfield_1 }; - bit_field.get(15, 1) == AUTONEG_COMPLETED + let phydev = self.0.get().cast_const(); + // SAFETY: By the type invariant of `Device`, `phydev` points to a valid + // `struct phy_device`, and there is no concurrent write to this field. + let completed = unsafe { bindings::phy_device::autoneg_complete_raw(phydev) }; + completed == 1 } /// Sets the speed of the PHY. -- 2.55.0