With CONFIG_CFI_CLANG, a callback function passed to
__queue_delayed_work from a module points to a jump table entry
defined in the module instead of the one used in the core kernel,
which breaks function address equality in this check:
WARN_ON_ONCE(timer->function != delayed_work_timer_fn);
Use WARN_ON_FUNCTION_MISMATCH() instead to disable the warning
when CFI and modules are both enabled.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210408182843.1754385-6-samitolvanen@google.com
struct work_struct *work = &dwork->work;
WARN_ON_ONCE(!wq);
- WARN_ON_ONCE(timer->function != delayed_work_timer_fn);
+ WARN_ON_FUNCTION_MISMATCH(timer->function, delayed_work_timer_fn);
WARN_ON_ONCE(timer_pending(timer));
WARN_ON_ONCE(!list_empty(&work->entry));