On Thu, 4 Feb 2021 07:25:55 +0000
HORIGUCHI NAOYA(堀口 直也) <naoya.horiguchi@xxxxxxx> wrote:
> Hi Aili,
>
> On Mon, Feb 01, 2021 at 04:17:49PM +0800, Aili Yao wrote:
> > When one page is already hwpoisoned by AO action, process may not be
> > killed, the process mapping this page may make a syscall include this
> > page and result to trigger a VM_FAULT_HWPOISON fault, if it's in kernel
> > mode it may be fixed by fixup_exception. Current code will just return
> > error code to user process.
> >
> > This is not sufficient, we should send a SIGBUS to the process and log
> > the info to console, as we can't trust the process will handle the error
> > correctly.
> >
> > Suggested-by: Feng Yang <yangfeng1@xxxxxxxxxxxx>
> > Signed-off-by: Aili Yao <yaoaili@xxxxxxxxxxxx>
> > ---
> ...
>
> > @@ -662,12 +662,32 @@ no_context(struct pt_regs *regs, unsigned long error_code,
> > * In this case we need to make sure we're not recursively
> > * faulting through the emulate_vsyscall() logic.
> > */
> > +
> > + if (IS_ENABLED(CONFIG_MEMORY_FAILURE) &&
> > + fault & (VM_FAULT_HWPOISON|VM_FAULT_HWPOISON_LARGE)) {
> > + unsigned int lsb = 0;
> > +
> > + pr_err("MCE: Killing %s:%d due to hardware memory corruption fault at %lx\n",
> > + current->comm, current->pid, address);
> > +
> > + sanitize_error_code(address, &error_code);
> > + set_signal_archinfo(address, error_code);
> > +
> > + if (fault & VM_FAULT_HWPOISON_LARGE)
> > + lsb = hstate_index_to_shift(VM_FAULT_GET_HINDEX(fault));
> > + if (fault & VM_FAULT_HWPOISON)
> > + lsb = PAGE_SHIFT;
> > +
> > + force_sig_mceerr(BUS_MCEERR_AR, (void __user *)address, lsb);
>
> This part contains some duplicated code with do_sigbus(), so some refactoring (like
> adding a common function) would be more helpful.
Yes, agree, I will modify this and rebase to the big fault series from tip.
Thanks
Aili Yao
