Callers that go through `kernel::prelude` have `CStrExt` in scope, but
code inside the `kernel` crate imports explicitly and may not. Using
`warn_on!` from such a module fails to build on UML, which is the only
configuration where `warn_flags!` needs a C string pointer rather than an
inline asm bug entry:
error[E0599]: no method named `as_char_ptr` found for reference `&ffi::CStr` in the current scope
--> linux/rust/kernel/bug.rs:83:49
|
83 | $crate::c_str!(::core::file!()).as_char_ptr(),
| ^^^^^^^^^^^
|
::: linux/rust/kernel/time.rs:427:9
|
427 | warn_on!(self.nanos < 0);
| ------------------------ in this macro invocation
|
= help: items from traits can only be used if the trait is in scope
= note: this error originates in the macro `$crate::warn_flags` which comes from the expansion of the macro `warn_on` (in Nightly builds, run with -Z mac)
help: trait `CStrExt` which provides `as_char_ptr` is implemented but not in scope; perhaps you want to import it
--> linux/rust/kernel/time.rs:27:1
|
27 + use crate::str::CStrExt;
Call the method through its fully qualified path, which resolves
without any import at the expansion site.
Cc: stable@vger.kernel.org
Fixes: dff64b0727 ("rust: Add warn_on macro")
Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Link: https://patch.msgid.link/20260807112427.1039056-1-tomo@flapping.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
30a449e04a