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| author | Benno Lossin <benno.lossin@proton.me> | 2025-03-05 13:29:01 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-03-22 12:56:53 -0700 |
| commit | 2c4216ade3ba921ed1706122a52e3ee47fc68a5f (patch) | |
| tree | f4659595100ed880f6ae42b3185733e93249f906 /rust | |
| parent | d2843ac3218fca6b26f496e2ff550a1fd8f9a86a (diff) | |
| download | linux-2c4216ade3ba921ed1706122a52e3ee47fc68a5f.tar.gz linux-2c4216ade3ba921ed1706122a52e3ee47fc68a5f.tar.bz2 linux-2c4216ade3ba921ed1706122a52e3ee47fc68a5f.zip | |
rust: init: fix `Zeroable` implementation for `Option<NonNull<T>>` and `Option<KBox<T>>`
commit df27cef153603b18a7d094b53cc3d5264ff32797 upstream.
According to [1], `NonNull<T>` and `#[repr(transparent)]` wrapper types
such as our custom `KBox<T>` have the null pointer optimization only if
`T: Sized`. Thus remove the `Zeroable` implementation for the unsized
case.
Link: https://doc.rust-lang.org/stable/std/option/index.html#representation [1]
Reported-by: Alice Ryhl <aliceryhl@google.com>
Closes: https://lore.kernel.org/rust-for-linux/CAH5fLghL+qzrD8KiCF1V3vf2YcC6aWySzkmaE2Zzrnh1gKj-hw@mail.gmail.com/
Cc: stable@vger.kernel.org # v6.12+ (a custom patch will be needed for 6.6.y)
Fixes: 38cde0bd7b67 ("rust: init: add `Zeroable` trait and `init::zeroed` function")
Signed-off-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Andreas Hindborg <a.hindborg@kernel.org>
Link: https://lore.kernel.org/r/20250305132836.2145476-1-benno.lossin@proton.me
[ Added Closes tag and moved up the Reported-by one. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'rust')
| -rw-r--r-- | rust/kernel/init.rs | 11 |
1 files changed, 4 insertions, 7 deletions
diff --git a/rust/kernel/init.rs b/rust/kernel/init.rs index c962029f96e1..d201954bd43f 100644 --- a/rust/kernel/init.rs +++ b/rust/kernel/init.rs @@ -1400,17 +1400,14 @@ impl_zeroable! { // SAFETY: `T: Zeroable` and `UnsafeCell` is `repr(transparent)`. {<T: ?Sized + Zeroable>} UnsafeCell<T>, - // SAFETY: All zeros is equivalent to `None` (option layout optimization guarantee). + // SAFETY: All zeros is equivalent to `None` (option layout optimization guarantee: + // https://doc.rust-lang.org/stable/std/option/index.html#representation). Option<NonZeroU8>, Option<NonZeroU16>, Option<NonZeroU32>, Option<NonZeroU64>, Option<NonZeroU128>, Option<NonZeroUsize>, Option<NonZeroI8>, Option<NonZeroI16>, Option<NonZeroI32>, Option<NonZeroI64>, Option<NonZeroI128>, Option<NonZeroIsize>, - - // SAFETY: All zeros is equivalent to `None` (option layout optimization guarantee). - // - // In this case we are allowed to use `T: ?Sized`, since all zeros is the `None` variant. - {<T: ?Sized>} Option<NonNull<T>>, - {<T: ?Sized>} Option<KBox<T>>, + {<T>} Option<NonNull<T>>, + {<T>} Option<KBox<T>>, // SAFETY: `null` pointer is valid. // |