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>

1 files changed, 4 insertions, 4 deletions

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 612a7c9795f6..d443dea95c27 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -906,7 +906,7 @@ int reuse_swap_page(struct page *page)
 {
         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 reuse_swap_page(struct page *page)
  */
 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 swap_info_struct *page_swap_info(struct page *page)
  */
 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 @@ EXPORT_SYMBOL_GPL(__page_file_mapping);
 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);