blob: 8a85426880987ea9ce31c6f10738b01075d15532 [file] [log] [blame]
.. title:: clang-tidy - linuxkernel-must-use-errs
Checks Linux kernel code to see if it uses the results from the functions in
``linux/err.h``. Also checks to see if code uses the results from functions that
directly return a value from one of these error functions.
This is important in the Linux kernel because ``ERR_PTR``, ``PTR_ERR``,
``IS_ERR``, ``IS_ERR_OR_NULL``, ``ERR_CAST``, and ``PTR_ERR_OR_ZERO`` return
values must be checked, since positive pointers and negative error codes are
being used in the same context. These functions are marked with
``__attribute__((warn_unused_result))``, but some kernel versions do not have
this warning enabled for clang.
.. code-block:: c
/* Trivial unused call to an ERR function */
/* A function that returns ERR_PTR. */
void *fn() { ERR_PTR(-EINVAL); }
/* An invalid use of fn. */