On Tue, May 12, 2026 at 10:21:50AM +0200, David Hildenbrand (Arm) wrote:
>
> > }
> > goto unlock_mutex;
> > } else if (res < 0) {
> > - if (is_reserved)
> > + /*
> > + * Promote a stable unhandlable kernel page diagnosed by
> > + * get_hwpoison_page() to MF_MSG_KERNEL alongside reserved
> > + * pages; transient lifecycle races stay as MF_MSG_GET_HWPOISON.
> > + */
> > + if (is_reserved || gp_status == MF_GET_PAGE_UNHANDLABLE)
> > res = action_result(pfn, MF_MSG_KERNEL, MF_IGNORED);
>
>
> It's all a bit of a mess. get_hwpoison_page() should just indicate that a page
> is unhandable if it is PG_reserved?
Are you saying that we should identify if the page is PG_reserved in
get_hwpoison_page() instead of in memory_failure(), as done in the
previous patch ("mm/memory-failure: report MF_MSG_KERNEL for reserved
pages") ?
> Why can't we just return a special error code from get_hwpoison_page()? We
> ahve
> plenty of errno values to chose from.
Something like:
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 866c4428ac7ef..0a6d83575833e 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -878,7 +878,7 @@ static const char *action_name[] = {
};
static const char * const action_page_types[] = {
- [MF_MSG_KERNEL] = "reserved kernel page",
+ [MF_MSG_KERNEL] = "unrecoverable kernel page",
[MF_MSG_KERNEL_HIGH_ORDER] = "high-order kernel page",
[MF_MSG_HUGE] = "huge page",
[MF_MSG_FREE_HUGE] = "free huge page",
@@ -1394,6 +1394,21 @@ static int get_any_page(struct page *p, unsigned long
flags)
int ret = 0, pass = 0;
bool count_increased = false;
+ if (PageReserved(p)) {
+ ret = -ENOTRECOVERABLE;
+ goto out;
+ }
+
if (flags & MF_COUNT_INCREASED)
count_increased = true;
@@ -1422,7 +1437,7 @@ static int get_any_page(struct page *p, unsigned long
flags)
shake_page(p);
goto try_again;
}
- ret = -EIO;
+ ret = -ENOTRECOVERABLE;
goto out;
}
}
@@ -1441,10 +1456,10 @@ static int get_any_page(struct page *p, unsigned long
flags)
goto try_again;
}
put_page(p);
- ret = -EIO;
+ ret = -ENOTRECOVERABLE;
}
out:
- if (ret == -EIO)
+ if (ret == -EIO || ret == -ENOTRECOVERABLE)
pr_err("%#lx: unhandlable page.\n", page_to_pfn(p));
return ret;
@@ -2431,6 +2448,9 @@ int memory_failure(unsigned long pfn, int flags)
res = action_result(pfn, MF_MSG_KERNEL_HIGH_ORDER,
MF_IGNORED);
}
goto unlock_mutex;
+ } else if (res == -ENOTRECOVERABLE) {
+ res = action_result(pfn, MF_MSG_KERNEL, MF_IGNORED);
+ goto unlock_mutex;
} else if (res < 0) {
res = action_result(pfn, MF_MSG_GET_HWPOISON, MF_IGNORED);
goto unlock_mutex;
If that is what you are suggestion, maybe we can create another
MF_MSG_RESERVED? and another return value for get_any_page() to track
the reserve pages ?
Thanks for the review and suggestions,
--breno
