RE: [PATCH v3 1/3] x86/mce: Use is_copy_from_user() to determine copy-from-user context

Luck, Tony
2025-03-06T18:15:59Z

> diff --git a/arch/x86/kernel/cpu/mce/severity.c b/arch/x86/kernel/cpu/mce/severity.c
> index dac4d64dfb2a..cb021058165f 100644
> --- a/arch/x86/kernel/cpu/mce/severity.c
> +++ b/arch/x86/kernel/cpu/mce/severity.c
> @@ -300,13 +300,12 @@ static noinstr int error_context(struct mce *m, struct pt_regs *regs)
> copy_user = is_copy_from_user(regs);
> instrumentation_end();
>
> - switch (fixup_type) {
> - case EX_TYPE_UACCESS:
> - if (!copy_user)
> - return IN_KERNEL;
> - m->kflags |= MCE_IN_KERNEL_COPYIN;
> - fallthrough;
> + if (copy_user) {
> + m->kflags |= MCE_IN_KERNEL_COPYIN | MCE_IN_KERNEL_COPYIN;

You have " MCE_IN_KERNEL_COPYIN" twice here.

> + return IN_KERNEL_RECOV
> + }
>
> + switch (fixup_type) {
> case EX_TYPE_FAULT_MCE_SAFE:
> case EX_TYPE_DEFAULT_MCE_SAFE:
> m->kflags |= MCE_IN_KERNEL_RECOV;
> --

-Tony