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/filemap.c b/mm/filemap.c
index b7749a9..7a7f3e0 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -409,9 +409,9 @@
{
int error;
- VM_BUG_ON(!PageLocked(old));
- VM_BUG_ON(!PageLocked(new));
- VM_BUG_ON(new->mapping);
+ VM_BUG_ON_PAGE(!PageLocked(old), old);
+ VM_BUG_ON_PAGE(!PageLocked(new), new);
+ VM_BUG_ON_PAGE(new->mapping, new);
error = radix_tree_preload(gfp_mask & ~__GFP_HIGHMEM);
if (!error) {
@@ -461,8 +461,8 @@
{
int error;
- VM_BUG_ON(!PageLocked(page));
- VM_BUG_ON(PageSwapBacked(page));
+ VM_BUG_ON_PAGE(!PageLocked(page), page);
+ VM_BUG_ON_PAGE(PageSwapBacked(page), page);
error = mem_cgroup_cache_charge(page, current->mm,
gfp_mask & GFP_RECLAIM_MASK);
@@ -607,7 +607,7 @@
*/
void unlock_page(struct page *page)
{
- VM_BUG_ON(!PageLocked(page));
+ VM_BUG_ON_PAGE(!PageLocked(page), page);
clear_bit_unlock(PG_locked, &page->flags);
smp_mb__after_clear_bit();
wake_up_page(page, PG_locked);
@@ -760,7 +760,7 @@
page_cache_release(page);
goto repeat;
}
- VM_BUG_ON(page->index != offset);
+ VM_BUG_ON_PAGE(page->index != offset, page);
}
return page;
}
@@ -1656,7 +1656,7 @@
put_page(page);
goto retry_find;
}
- VM_BUG_ON(page->index != offset);
+ VM_BUG_ON_PAGE(page->index != offset, page);
/*
* We have a locked page in the page cache, now we need to check