mm: dump page when hitting a VM_BUG_ON using VM_BUG_ON_PAGE
Most of the VM_BUG_ON assertions are performed on a page. Usually, when
one of these assertions fails we'll get a BUG_ON with a call stack and
the registers.
I've recently noticed based on the requests to add a small piece of code
that dumps the page to various VM_BUG_ON sites that the page dump is
quite useful to people debugging issues in mm.
This patch adds a VM_BUG_ON_PAGE(cond, page) which beyond doing what
VM_BUG_ON() does, also dumps the page before executing the actual
BUG_ON.
[akpm@linux-foundation.org: fix up includes]
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 612a7c9..d443dea 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -906,7 +906,7 @@
{
int count;
- VM_BUG_ON(!PageLocked(page));
+ VM_BUG_ON_PAGE(!PageLocked(page), page);
if (unlikely(PageKsm(page)))
return 0;
count = page_mapcount(page);
@@ -926,7 +926,7 @@
*/
int try_to_free_swap(struct page *page)
{
- VM_BUG_ON(!PageLocked(page));
+ VM_BUG_ON_PAGE(!PageLocked(page), page);
if (!PageSwapCache(page))
return 0;
@@ -2714,7 +2714,7 @@
*/
struct address_space *__page_file_mapping(struct page *page)
{
- VM_BUG_ON(!PageSwapCache(page));
+ VM_BUG_ON_PAGE(!PageSwapCache(page), page);
return page_swap_info(page)->swap_file->f_mapping;
}
EXPORT_SYMBOL_GPL(__page_file_mapping);
@@ -2722,7 +2722,7 @@
pgoff_t __page_file_index(struct page *page)
{
swp_entry_t swap = { .val = page_private(page) };
- VM_BUG_ON(!PageSwapCache(page));
+ VM_BUG_ON_PAGE(!PageSwapCache(page), page);
return swp_offset(swap);
}
EXPORT_SYMBOL_GPL(__page_file_index);