If page is poisoned, it will crash when we call some page related
functions, so must check whether the page is poisoned or not firstly.
Fixes: 6197ab984b41 ("mm: improve dump_page() for compound pages")
Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
---
mm/debug.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)
diff --git a/mm/debug.c b/mm/debug.c
index 84cdcd0f7bd3..cf84cd9df527 100644
--- a/mm/debug.c
+++ b/mm/debug.c
@@ -44,20 +44,19 @@ const struct trace_print_flags vmaflag_names[] = {
static void __dump_page(struct page *page, const char *reason)
{
- struct page *head = compound_head(page);
+ struct page *head = NULL;
struct address_space *mapping;
- bool page_poisoned = PagePoisoned(page);
- bool compound = PageCompound(page);
+ bool compound;
/*
* Accessing the pageblock without the zone lock. It could change to
* "isolate" again in the meantime, but since we are just dumping the
* state for debugging, it should be fine to accept a bit of
* inaccuracy here due to racing.
*/
- bool page_cma = is_migrate_cma_page(page);
+ bool page_cma;
int mapcount;
char *type = "";
-
+ bool page_poisoned = PagePoisoned(page);
/*
* If struct page is poisoned don't access Page*() functions as that
* leads to recursive loop. Page*() check for poisoned pages, and calls
@@ -68,6 +67,10 @@ static void __dump_page(struct page *page, const char *reason)
goto hex_only;
}
+ head = compound_head(page);
+ page_poisoned = PagePoisoned(page);
+ page_cma = is_migrate_cma_page(page);
+
if (page < head || (page >= head + MAX_ORDER_NR_PAGES)) {
/*
* Corrupt page, so we cannot call page_mapping. Instead, do a
@@ -178,7 +181,7 @@ static void __dump_page(struct page *page, const char *reason)
print_hex_dump(KERN_WARNING, "raw: ", DUMP_PREFIX_NONE, 32,
sizeof(unsigned long), page,
sizeof(struct page), false);
- if (head != page)
+ if (head && head != page)
print_hex_dump(KERN_WARNING, "head: ", DUMP_PREFIX_NONE, 32,
sizeof(unsigned long), head,
sizeof(struct page), false);
--
2.26.2
