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rust: devres: fix leaking call to devm_add_action()

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When the data argument of Devres::new() is Err(), we leak the preceding
call to devm_add_action().

In order to fix this, call devm_add_action() in a unit type initializer in
try_pin_init!() after the initializers of all other fields.

Fixes: f5d3ef25d2 ("rust: devres: get rid of Devres' inner Arc")
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Link: https://lore.kernel.org/r/20250812130928.11075-1-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
This commit is contained in:
Danilo Krummrich 2025-08-12 15:09:06 +02:00
parent a5ba9ad417
commit 75a7b151e8
1 changed files with 18 additions and 9 deletions
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27
rust/kernel/devres.rs
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@ -115,10 +115,11 @@ pub struct Devres<T: Send> {
/// Contains all the fields shared with [`Self::callback`].
// TODO: Replace with `UnsafePinned`, once available.
//
// Subsequently, the `drop_in_place()` in `Devres::drop` and the explicit `Send` and `Sync'
// impls can be removed.
// Subsequently, the `drop_in_place()` in `Devres::drop` and `Devres::new` as well as the
// explicit `Send` and `Sync' impls can be removed.
#[pin]
inner: Opaque<Inner<T>>,
_add_action: (),
}
impl<T: Send> Devres<T> {
@ -140,7 +141,15 @@ impl<T: Send> Devres<T> {
dev: dev.into(),
callback,
// INVARIANT: `inner` is properly initialized.
inner <- {
inner <- Opaque::pin_init(try_pin_init!(Inner {
devm <- Completion::new(),
revoke <- Completion::new(),
data <- Revocable::new(data),
})),
// TODO: Replace with "initializer code blocks" [1] once available.
//
// [1] https://github.com/Rust-for-Linux/pin-init/pull/69
_add_action: {
// SAFETY: `this` is a valid pointer to uninitialized memory.
let inner = unsafe { &raw mut (*this.as_ptr()).inner };
@ -152,13 +161,13 @@ impl<T: Send> Devres<T> {
// live at least as long as the returned `impl PinInit<Self, Error>`.
to_result(unsafe {
bindings::devm_add_action(dev.as_raw(), Some(callback), inner.cast())
})?;
}).inspect_err(|_| {
let inner = Opaque::cast_into(inner);
Opaque::pin_init(try_pin_init!(Inner {
devm <- Completion::new(),
revoke <- Completion::new(),
data <- Revocable::new(data),
}))
// SAFETY: `inner` is a valid pointer to an `Inner<T>` and valid for both reads
// and writes.
unsafe { core::ptr::drop_in_place(inner) };
})?;
},
})
}