On Tue, 21 Nov 2023 23:00:55 +0100
Ilya Leoshkevich <iii@xxxxxxxxxxxxx> wrote:
> Architectures use assembly code to initialize ftrace_regs and call
> ftrace_ops_list_func(). Therefore, from the KMSAN's point of view,
> ftrace_regs is poisoned on ftrace_ops_list_func entry(). This causes
> KMSAN warnings when running the ftrace testsuite.
>
> Fix by trusting the architecture-specific assembly code and always
> unpoisoning ftrace_regs in ftrace_ops_list_func.
You must be very trusting to trust architecture-specific assembly code ;-)
Acked-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
-- Steve
>
> Signed-off-by: Ilya Leoshkevich <iii@xxxxxxxxxxxxx>
> ---
> kernel/trace/ftrace.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
> index 8de8bec5f366..dfb8b26966aa 100644
> --- a/kernel/trace/ftrace.c
> +++ b/kernel/trace/ftrace.c
> @@ -7399,6 +7399,7 @@ __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
> void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
> struct ftrace_ops *op, struct ftrace_regs *fregs)
> {
> + kmsan_unpoison_memory(fregs, sizeof(*fregs));
> __ftrace_ops_list_func(ip, parent_ip, NULL, fregs);
> }
> #else
