linux/rust
Danilo Krummrich 97ab3e8eec rust: alloc: fix dangling pointer in VecExt<T>::reserve()
Currently, a Vec<T>'s ptr value, after calling Vec<T>::new(), is
initialized to Unique::dangling(). Hence, in VecExt<T>::reserve(), we're
passing a dangling pointer (instead of NULL) to krealloc() whenever a new
Vec<T>'s backing storage is allocated through VecExt<T> extension
functions.

This only works as long as align_of::<T>(), used by Unique::dangling() to
derive the dangling pointer, resolves to a value between 0x0 and
ZERO_SIZE_PTR (0x10) and krealloc() hence treats it the same as a NULL
pointer however.

This isn't a case we should rely on, since there may be types whose
alignment may exceed the range still covered by krealloc(), plus other
kernel allocators are not as tolerant either.

Instead, pass a real NULL pointer to krealloc_aligned() if Vec<T>'s
capacity is zero.

Fixes: 5ab560ce12 ("rust: alloc: update `VecExt` to take allocation flags")
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Signed-off-by: Danilo Krummrich <dakr@redhat.com>
Reviewed-by: Wedson Almeida Filho <walmeida@microsoft.com>
Link: https://lore.kernel.org/r/20240501134834.22323-1-dakr@redhat.com
[ Solved `use` conflict and applied the `if`-instead-of-`match` change
  discussed in the list. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-05-08 00:43:30 +02:00
..
bindings rust: alloc: introduce allocation flags 2024-04-16 22:05:06 +02:00
kernel rust: alloc: fix dangling pointer in VecExt<T>::reserve() 2024-05-08 00:43:30 +02:00
macros rust: macros: allow generic parameter default values in #[pin_data] 2024-04-07 22:03:42 +02:00
uapi net: phy: add Rust Asix PHY driver 2023-12-15 09:35:50 +00:00
.gitignore rust: support running Rust documentation tests as KUnit ones 2023-07-19 09:32:53 -06:00
bindgen_parameters rust: Ignore preserve-most functions 2023-12-13 01:09:55 +01:00
build_error.rs rust: add build_error crate 2022-12-04 01:59:16 +01:00
compiler_builtins.rs rust: upgrade to Rust 1.73.0 2023-10-15 21:25:08 +02:00
exports.c rust: replace <linux/module.h> with <linux/export.h> in rust/exports.c 2023-12-13 01:09:55 +01:00
helpers.c rust: helpers: Fix grammar in comment 2024-05-05 18:09:04 +02:00
Makefile kbuild: use the upstream alloc crate 2024-04-16 22:03:14 +02:00