impl_list_item_mod.rs calls container_of() without unsafe blocks at a couple of places. Since container_of() is an unsafe macro / function, the blocks are strictly necessary.
For unknown reasons, that problem was so far not visible and only gets visible once one utilizes the list implementation from within the core crate:
error[E0133]: call to unsafe function `core::ptr::mut_ptr::<impl *mut T>::byte_sub` is unsafe and requires unsafe block --> rust/kernel/lib.rs:252:29 | 252 | let container_ptr = field_ptr.byte_sub(offset).cast::<$Container>(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^ call to unsafe function | ::: rust/kernel/drm/jq.rs:98:1 | 98 | / impl_list_item! { 99 | | impl ListItem<0> for BasicItem { using ListLinks { self.links }; } 100 | | } | |_- in this macro invocation | note: an unsafe function restricts its caller, but its body is safe by default --> rust/kernel/list/impl_list_item_mod.rs:216:13 | 216 | unsafe fn view_value(me: *mut $crate::list::ListLinks<$num>) -> *const Self { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | ::: rust/kernel/drm/jq.rs:98:1 | 98 | / impl_list_item! { 99 | | impl ListItem<0> for BasicItem { using ListLinks { self.links }; } 100 | | } | |_- in this macro invocation = note: requested on the command line with `-D unsafe-op-in-unsafe-fn` = note: this error originates in the macro `$crate::container_of` which comes from the expansion of the macro `impl_list_item`
Add unsafe blocks to container_of to fix the issue.
Cc: stable@vger.kernel.org # v6.17+ Fixes: c77f85b347dd ("rust: list: remove OFFSET constants") Suggested-by: Alice Ryhl aliceryhl@google.com Signed-off-by: Philipp Stanner phasta@kernel.org --- Changes in v2: - Add unsafes to the list implementation instead of container_of itself. (Alice, Miguel) - Adjust commit message and Fixes: tag. - Add stable-kernel for completeness. --- rust/kernel/list/impl_list_item_mod.rs | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/rust/kernel/list/impl_list_item_mod.rs b/rust/kernel/list/impl_list_item_mod.rs index 202bc6f97c13..7052095efde5 100644 --- a/rust/kernel/list/impl_list_item_mod.rs +++ b/rust/kernel/list/impl_list_item_mod.rs @@ -217,7 +217,7 @@ unsafe fn view_value(me: *mut $crate::list::ListLinks<$num>) -> *const Self { // SAFETY: `me` originates from the most recent call to `prepare_to_insert`, so it // points at the field `$field` in a value of type `Self`. Thus, reversing that // operation is still in-bounds of the allocation. - $crate::container_of!(me, Self, $($field).*) + unsafe { $crate::container_of!(me, Self, $($field).*) } }
// GUARANTEES: @@ -242,7 +242,7 @@ unsafe fn post_remove(me: *mut $crate::list::ListLinks<$num>) -> *const Self { // SAFETY: `me` originates from the most recent call to `prepare_to_insert`, so it // points at the field `$field` in a value of type `Self`. Thus, reversing that // operation is still in-bounds of the allocation. - $crate::container_of!(me, Self, $($field).*) + unsafe { $crate::container_of!(me, Self, $($field).*) } } } )*}; @@ -270,9 +270,9 @@ unsafe fn prepare_to_insert(me: *const Self) -> *mut $crate::list::ListLinks<$nu // SAFETY: The caller promises that `me` points at a valid value of type `Self`. let links_field = unsafe { <Self as $crate::list::ListItem<$num>>::view_links(me) };
- let container = $crate::container_of!( + let container = unsafe { $crate::container_of!( links_field, $crate::list::ListLinksSelfPtr<Self, $num>, inner - ); + ) };
// SAFETY: By the same reasoning above, `links_field` is a valid pointer. let self_ptr = unsafe { @@ -319,9 +319,9 @@ unsafe fn view_links(me: *const Self) -> *mut $crate::list::ListLinks<$num> { // `ListArc` containing `Self` until the next call to `post_remove`. The value cannot // be destroyed while a `ListArc` reference exists. unsafe fn view_value(links_field: *mut $crate::list::ListLinks<$num>) -> *const Self { - let container = $crate::container_of!( + let container = unsafe { $crate::container_of!( links_field, $crate::list::ListLinksSelfPtr<Self, $num>, inner - ); + ) };
// SAFETY: By the same reasoning above, `links_field` is a valid pointer. let self_ptr = unsafe {