From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 4C64E226D0F; Mon, 18 Aug 2025 13:38:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755524331; cv=none; b=nq6qQtIWjAg6yLwUqcgsrckkwr9sHMmCMoB9BJwjEN3YMmkhoTPfcWRL+7fUkpHU8ADSZXzyoNN+CMQ5Y8wUpRsyldwF+yamJ2axqOKFTpNk9XOm8DOxoUzjT2kpMoVCwbj/zZLldIK5PzDwsNyrTu6POLJcdv6ZuH1/HadbsAM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755524331; c=relaxed/simple; bh=Y+wzTHcIi+7fCE5zpYhweowuW6JQT9XNmhcm1kVUNG4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=fLvnzWnLarrj7vovlVpQEM9tGbxa3QpSzOeD2Y6nTay7QWuZyHE4SnguDaN9AW5J+hEX3uf3mqEPa8zoSyXcpwTMkyVu9X3FlfBgYeoc76yvSpfKEzANi53MgvBBgxgfmxj1qXwEkcTycgt/swgJe9A00Xv2HjIjgYB1COryz64= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=VHC5qQyg; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="VHC5qQyg" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C04AEC4CEF1; Mon, 18 Aug 2025 13:38:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1755524331; bh=Y+wzTHcIi+7fCE5zpYhweowuW6JQT9XNmhcm1kVUNG4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VHC5qQyg1WFR8Ixgdb2/isQSZl9jZQfRt+S0goggSMMKPiYhC4Qets6VZvft4bVjz d8mBIKKQZDwSFQi4x54+wQOALL2Ramw/xR9rJ1nHmX5UnDwnVtoZsjayho+wn+H4PL eff2b/BqH1NfqRUwi4zOw8hVLEfxBeYQdGdh3b50= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Konrad Dybcio , Alice Ryhl , Miguel Ojeda Subject: [PATCH 6.15 440/515] rust: workaround `rustdoc` target modifiers bug Date: Mon, 18 Aug 2025 14:47:06 +0200 Message-ID: <20250818124515.363246915@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250818124458.334548733@linuxfoundation.org> References: <20250818124458.334548733@linuxfoundation.org> User-Agent: quilt/0.68 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 6.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Miguel Ojeda commit abbf9a44944171ca99c150adad9361a2f517d3b6 upstream. Starting with Rust 1.88.0 (released 2025-06-26), `rustdoc` complains about a target modifier mismatch in configurations where `-Zfixed-x18` is passed: error: mixing `-Zfixed-x18` will cause an ABI mismatch in crate `rust_out` | = help: the `-Zfixed-x18` flag modifies the ABI so Rust crates compiled with different values of this flag cannot be used together safely = note: unset `-Zfixed-x18` in this crate is incompatible with `-Zfixed-x18=` in dependency `core` = help: set `-Zfixed-x18=` in this crate or unset `-Zfixed-x18` in `core` = help: if you are sure this will not cause problems, you may use `-Cunsafe-allow-abi-mismatch=fixed-x18` to silence this error The reason is that `rustdoc` was not passing the target modifiers when configuring the session options, and thus it would report a mismatch that did not exist as soon as a target modifier is used in a dependency. We did not notice it in the kernel until now because `-Zfixed-x18` has been a target modifier only since 1.88.0 (and it is the only one we use so far). The issue has been reported upstream [1] and a fix has been submitted [2], including a test similar to the kernel case. [ This is now fixed upstream (thanks Guillaume for the quick review), so it will be fixed in Rust 1.90.0 (expected 2025-09-18). - Miguel ] Meanwhile, conditionally pass `-Cunsafe-allow-abi-mismatch=fixed-x18` to workaround the issue on our side. Cc: stable@vger.kernel.org # Needed in 6.12.y and later (Rust is pinned in older LTSs). Reported-by: Konrad Dybcio Closes: https://lore.kernel.org/rust-for-linux/36cdc798-524f-4910-8b77-d7b9fac08d77@oss.qualcomm.com/ Link: https://github.com/rust-lang/rust/issues/144521 [1] Link: https://github.com/rust-lang/rust/pull/144523 [2] Reviewed-by: Alice Ryhl Link: https://lore.kernel.org/r/20250727092317.2930617-1-ojeda@kernel.org Signed-off-by: Miguel Ojeda Signed-off-by: Greg Kroah-Hartman --- rust/Makefile | 6 ++++++ 1 file changed, 6 insertions(+) --- a/rust/Makefile +++ b/rust/Makefile @@ -62,6 +62,10 @@ core-cfgs = \ core-edition := $(if $(call rustc-min-version,108700),2024,2021) +# `rustdoc` did not save the target modifiers, thus workaround for +# the time being (https://github.com/rust-lang/rust/issues/144521). +rustdoc_modifiers_workaround := $(if $(call rustc-min-version,108800),-Cunsafe-allow-abi-mismatch=fixed-x18) + # `rustc` recognizes `--remap-path-prefix` since 1.26.0, but `rustdoc` only # since Rust 1.81.0. Moreover, `rustdoc` ICEs on out-of-tree builds since Rust # 1.82.0 (https://github.com/rust-lang/rust/issues/138520). Thus workaround both @@ -74,6 +78,7 @@ quiet_cmd_rustdoc = RUSTDOC $(if $(rustd -Zunstable-options --generate-link-to-definition \ --output $(rustdoc_output) \ --crate-name $(subst rustdoc-,,$@) \ + $(rustdoc_modifiers_workaround) \ $(if $(rustdoc_host),,--sysroot=/dev/null) \ @$(objtree)/include/generated/rustc_cfg $< @@ -216,6 +221,7 @@ quiet_cmd_rustdoc_test_kernel = RUSTDOC --extern bindings --extern uapi \ --no-run --crate-name kernel -Zunstable-options \ --sysroot=/dev/null \ + $(rustdoc_modifiers_workaround) \ --test-builder $(objtree)/scripts/rustdoc_test_builder \ $< $(rustdoc_test_kernel_quiet); \ $(objtree)/scripts/rustdoc_test_gen