6.12-stable review patch. If anyone has any objections, please let me know.
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From: Miguel Ojeda ojeda@kernel.org
[ Upstream commit fad472efab0a805dd939f017c5b8669a786a4bcf ]
The `rustdoc` modifiers bug [1] was fixed in Rust 1.90.0 [2], for which we added a workaround in commit abbf9a449441 ("rust: workaround `rustdoc` target modifiers bug").
However, `rustdoc`'s doctest generation still has a similar issue [3], being fixed at [4], which does not affect us because we apply the workaround to both, and now, starting with Rust 1.91.0 (released 2025-10-30), `-Zsanitizer` is a target modifier too [5], which means we fail with:
RUSTDOC TK rust/kernel/lib.rs error: mixing `-Zsanitizer` will cause an ABI mismatch in crate `kernel` --> rust/kernel/lib.rs:3:1 | 3 | //! The `kernel` crate. | ^ | = help: the `-Zsanitizer` flag modifies the ABI so Rust crates compiled with different values of this flag cannot be used together safely = note: unset `-Zsanitizer` in this crate is incompatible with `-Zsanitizer=kernel-address` in dependency `core` = help: set `-Zsanitizer=kernel-address` in this crate or unset `-Zsanitizer` in `core` = help: if you are sure this will not cause problems, you may use `-Cunsafe-allow-abi-mismatch=sanitizer` to silence this error
A simple way around is to add the sanitizer to the list in the existing workaround (especially if we had not started to pass the sanitizer flags in the previous commit, since in that case that would not be necessary). However, that still applies the workaround in more cases than necessary.
Instead, only modify the doctests flags to ignore the check for sanitizers, so that it is more local (and thus the compiler keeps checking it for us in the normal `rustdoc` calls). Since the previous commit already treated the `rustdoc` calls as kernel objects, this should allow us in the future to easily remove this workaround when the time comes.
By the way, the `-Cunsafe-allow-abi-mismatch` flag overwrites previous ones rather than appending, so it needs to be all done in the same flag. Moreover, unknown modifiers are rejected, and thus we have to gate based on the version too.
Finally, `-Zsanitizer-cfi-normalize-integers` is not affected (in Rust 1.91.0), so it is not needed in the workaround for the moment.
Cc: stable@vger.kernel.org # Needed in 6.12.y and later (Rust is pinned in older LTSs). Link: https://github.com/rust-lang/rust/issues/144521 [1] Link: https://github.com/rust-lang/rust/pull/144523 [2] Link: https://github.com/rust-lang/rust/issues/146465 [3] Link: https://github.com/rust-lang/rust/pull/148068 [4] Link: https://github.com/rust-lang/rust/pull/138736 [5] Reviewed-by: Alice Ryhl aliceryhl@google.com Tested-by: Justin M. Forbes jforbes@fedoraproject.org Link: https://patch.msgid.link/20251102212853.1505384-2-ojeda@kernel.org Signed-off-by: Miguel Ojeda ojeda@kernel.org [ added --remap-path-prefix comments missing in stable branch ] Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- rust/Makefile | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/rust/Makefile +++ b/rust/Makefile @@ -59,6 +59,8 @@ core-edition := $(if $(call rustc-min-ve # 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)
+# Similarly, for doctests (https://github.com/rust-lang/rust/issues/146465). +doctests_modifiers_workaround := $(rustdoc_modifiers_workaround)$(if $(call rustc-min-version,109100),$(comma)sanitizer) quiet_cmd_rustdoc = RUSTDOC $(if $(rustdoc_host),H, ) $< cmd_rustdoc = \ OBJTREE=$(abspath $(objtree)) \ @@ -189,7 +191,7 @@ quiet_cmd_rustdoc_test_kernel = RUSTDOC --extern bindings --extern uapi \ --no-run --crate-name kernel -Zunstable-options \ --sysroot=/dev/null \ - $(rustdoc_modifiers_workaround) \ + $(doctests_modifiers_workaround) \ --test-builder $(objtree)/scripts/rustdoc_test_builder \ $< $(rustdoc_test_kernel_quiet); \ $(objtree)/scripts/rustdoc_test_gen