On Sat, Aug 19, 2023 at 06:22:12PM +0800, Shuai Xue wrote:
> When a process tries to access a page that is already offline
How does this happen?
> the kernel will send a sigbus signal with the BUS_MCEERR_AR code. This
> signal is typically handled by a registered sigbus handler in the
> process. However, if the process does not have a registered sigbus
> handler, it is important for end users to be informed about what
> happened.
>
> To address this, add an error message similar to those implemented on
> the x86, powerpc, and parisc platforms.
>
> Signed-off-by: Shuai Xue <xueshuai@xxxxxxxxxxxxxxxxx>
> ---
> arch/arm64/mm/fault.c | 2 ++
> arch/parisc/mm/fault.c | 5 ++---
> arch/x86/mm/fault.c | 3 +--
> 3 files changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
> index 3fe516b32577..38e2186882bd 100644
> --- a/arch/arm64/mm/fault.c
> +++ b/arch/arm64/mm/fault.c
> @@ -679,6 +679,8 @@ static int __kprobes do_page_fault(unsigned long far, unsigned long esr,
> } else if (fault & (VM_FAULT_HWPOISON_LARGE | VM_FAULT_HWPOISON)) {
> unsigned int lsb;
>
> + pr_err("MCE: Killing %s:%d due to hardware memory corruption fault at %lx\n",
> + current->comm, current->pid, far);
> lsb = PAGE_SHIFT;
> if (fault & VM_FAULT_HWPOISON_LARGE)
> lsb = hstate_index_to_shift(VM_FAULT_GET_HINDEX(fault));
Hmm, I'm not convinced by this. We have 'show_unhandled_signals' already,
and there's plenty of code in memory-failure.c for handling poisoned pages
reported by e.g. GHES. I don't think dumping extra messages in dmesg from
the arch code really adds anything.
Will
