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authorMiguel Ojeda <ojeda@kernel.org>2023-08-23 18:02:42 +0200
committerMiguel Ojeda <ojeda@kernel.org>2023-10-05 13:29:50 +0200
commit828176d037e29f813792a8b3ac1591834240e96f (patch)
tree2af99cd9707b411f96cceeb9ffe4df654496c210 /rust
parent8a749fd1a8720d4619c91c8b6e7528c0a355c0aa (diff)
rust: arc: add explicit `drop()` around `Box::from_raw()`
`Box::from_raw()` is `#[must_use]`, which means the result cannot go unused. In Rust 1.71.0, this was not detected because the block expression swallows the diagnostic [1]: unsafe { Box::from_raw(self.ptr.as_ptr()) }; It would have been detected, however, if the line had been instead: unsafe { Box::from_raw(self.ptr.as_ptr()); } i.e. the semicolon being inside the `unsafe` block, rather than outside. In Rust 1.72.0, the compiler started warning about this [2], so without this patch we will get: error: unused return value of `alloc::boxed::Box::<T>::from_raw` that must be used --> rust/kernel/sync/arc.rs:302:22 | 302 | unsafe { Box::from_raw(self.ptr.as_ptr()) }; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | = note: call `drop(Box::from_raw(ptr))` if you intend to drop the `Box` = note: `-D unused-must-use` implied by `-D warnings` help: use `let _ = ...` to ignore the resulting value | 302 | unsafe { let _ = Box::from_raw(self.ptr.as_ptr()); }; | +++++++ + Thus add an add an explicit `drop()` as the `#[must_use]`'s annotation suggests (instead of the more general help line). Link: https://github.com/rust-lang/rust/issues/104253 [1] Link: https://github.com/rust-lang/rust/pull/112529 [2] Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com> Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Link: https://lore.kernel.org/r/20230823160244.188033-2-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Diffstat (limited to 'rust')
-rw-r--r--rust/kernel/sync/arc.rs2
1 files changed, 1 insertions, 1 deletions
diff --git a/rust/kernel/sync/arc.rs b/rust/kernel/sync/arc.rs
index 3d496391a9bd..7f04e4f00a2c 100644
--- a/rust/kernel/sync/arc.rs
+++ b/rust/kernel/sync/arc.rs
@@ -302,7 +302,7 @@ impl<T: ?Sized> Drop for Arc<T> {
// The count reached zero, we must free the memory.
//
// SAFETY: The pointer was initialised from the result of `Box::leak`.
- unsafe { Box::from_raw(self.ptr.as_ptr()) };
+ unsafe { drop(Box::from_raw(self.ptr.as_ptr())) };
}
}
}