Re: [PATCH v4 5/5] powerpc/mce: hookup memory_failure for UE errors

Balbir Singh [off-list ref] writes:

On Mon, Oct 16, 2017 at 4:38 PM, Michael Ellerman [off-list ref] wrote:

quoted

Balbir Singh [off-list ref] writes:

quoted

If we are in user space and hit a UE error, we now have the
basic infrastructure to walk the page tables and find out
the effective address that was accessed, since the DAR
is not valid.

We use a work_queue content to hookup the bad pfn, any
other context causes problems, since memory_failure itself
can call into schedule() via lru_drain_ bits.

We could probably poison the struct page to avoid a race
between detection and taking corrective action.

Signed-off-by: Balbir Singh <bsingharora@gmail.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
---
 arch/powerpc/kernel/mce.c | 70 +++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 67 insertions(+), 3 deletions(-)

I'm not sure why this is in mce.c but the rest was in mce_power.c ?

The way the code is organized is that save_mce_event is implemented here
and called from mce_power.c. save_mce_event() does the processing
of the event.

save_mce_event() is only called from mce_power.c :/

I'd be happy if it was mce_real_mode.c and mce.c, that would be a good
distinction to make.

Though even then, most of the code is Book3s64 specific I think so maybe
it shouldn't be in just mce.c.

Anyway I'll merge this and we can improve things later.

cheers