FAILED: patch "[PATCH] rust: Disallow BTF generation with Rust + LTO" failed to apply to 6.6-stable tree

FAILED: patch "[PATCH] rust: Disallow BTF generation with Rust + LTO" failed to apply to 6.6-stable tree

[gregkh]

The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x 5daa0c35a1f0e7a6c3b8ba9cb721e7d1ace6e619
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2025031621-july-parkway-796f@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 5daa0c35a1f0e7a6c3b8ba9cb721e7d1ace6e619 Mon Sep 17 00:00:00 2001
From: Matthew Maurer <mmaurer@google.com>
Date: Wed, 8 Jan 2025 23:35:08 +0000
Subject: [PATCH] rust: Disallow BTF generation with Rust + LTO

The kernel cannot currently self-parse BTF containing Rust debug
information. pahole uses the language of the CU to determine whether to
filter out debug information when generating the BTF. When LTO is
enabled, Rust code can cross CU boundaries, resulting in Rust debug
information in CUs labeled as C. This results in a system which cannot
parse its own BTF.

Signed-off-by: Matthew Maurer <mmaurer@google.com>
Cc: stable@vger.kernel.org
Fixes: c1177979af9c ("btf, scripts: Exclude Rust CUs with pahole")
Link: https://lore.kernel.org/r/20250108-rust-btf-lto-incompat-v1-1-60243ff6d820@google.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

diff --git a/init/Kconfig b/init/Kconfig
index d0d021b3fa3b..324c2886b2ea 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1973,7 +1973,7 @@ config RUST
 	depends on !MODVERSIONS || GENDWARFKSYMS
 	depends on !GCC_PLUGIN_RANDSTRUCT
 	depends on !RANDSTRUCT
-	depends on !DEBUG_INFO_BTF || PAHOLE_HAS_LANG_EXCLUDE
+	depends on !DEBUG_INFO_BTF || (PAHOLE_HAS_LANG_EXCLUDE && !LTO)
 	depends on !CFI_CLANG || HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC
 	select CFI_ICALL_NORMALIZE_INTEGERS if CFI_CLANG
 	depends on !CALL_PADDING || RUSTC_VERSION >= 108100

[PATCH 6.6.y] rust: Disallow BTF generation with Rust + LTO

[Miguel Ojeda]

From: Matthew Maurer <mmaurer@google.com>

commit 5daa0c35a1f0e7a6c3b8ba9cb721e7d1ace6e619 upstream.

The kernel cannot currently self-parse BTF containing Rust debug
information. pahole uses the language of the CU to determine whether to
filter out debug information when generating the BTF. When LTO is
enabled, Rust code can cross CU boundaries, resulting in Rust debug
information in CUs labeled as C. This results in a system which cannot
parse its own BTF.

Signed-off-by: Matthew Maurer <mmaurer@google.com>
Cc: stable@vger.kernel.org
Fixes: c1177979af9c ("btf, scripts: Exclude Rust CUs with pahole")
Link: https://lore.kernel.org/r/20250108-rust-btf-lto-incompat-v1-1-60243ff6d820@google.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
 init/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/init/Kconfig b/init/Kconfig
index 60ed7713b5ee..1105cb53f391 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1908,7 +1908,7 @@ config RUST
 	depends on !GCC_PLUGINS
 	depends on !RANDSTRUCT
 	depends on !SHADOW_CALL_STACK
-	depends on !DEBUG_INFO_BTF || PAHOLE_HAS_LANG_EXCLUDE
+	depends on !DEBUG_INFO_BTF || (PAHOLE_HAS_LANG_EXCLUDE && !LTO)
 	help
 	  Enables Rust support in the kernel.
 
-- 
2.49.0

Re: [PATCH 6.6.y] rust: Disallow BTF generation with Rust + LTO

[Sasha Levin]

[ Sasha's backport helper bot ]

Hi,

✅ All tests passed successfully. No issues detected.
No action required from the submitter.

The upstream commit SHA1 provided is correct: 5daa0c35a1f0e7a6c3b8ba9cb721e7d1ace6e619

WARNING: Author mismatch between patch and upstream commit:
Backport author: Miguel Ojeda<ojeda@kernel.org>
Commit author: Matthew Maurer<mmaurer@google.com>

Status in newer kernel trees:
6.13.y | Present (different SHA1: d0ae348de14f)
6.12.y | Present (different SHA1: 9565f4e43f2f)

Note: The patch differs from the upstream commit:
---
1:  5daa0c35a1f0e < -:  ------------- rust: Disallow BTF generation with Rust + LTO
-:  ------------- > 1:  fe3c31b5a6c87 rust: Disallow BTF generation with Rust + LTO
---

Results of testing on various branches:

| Branch                    | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-6.6.y        |  Success    |  Success   |