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/memory.c b/mm/memory.c
index 71d70c0..be6a0c0 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -289,7 +289,7 @@
return 0;
batch = tlb->active;
}
- VM_BUG_ON(batch->nr > batch->max);
+ VM_BUG_ON_PAGE(batch->nr > batch->max, page);
return batch->max - batch->nr;
}
@@ -2702,7 +2702,7 @@
goto unwritable_page;
}
} else
- VM_BUG_ON(!PageLocked(old_page));
+ VM_BUG_ON_PAGE(!PageLocked(old_page), old_page);
/*
* Since we dropped the lock we need to revalidate
@@ -3358,7 +3358,7 @@
if (unlikely(!(ret & VM_FAULT_LOCKED)))
lock_page(vmf.page);
else
- VM_BUG_ON(!PageLocked(vmf.page));
+ VM_BUG_ON_PAGE(!PageLocked(vmf.page), vmf.page);
/*
* Should we do an early C-O-W break?
@@ -3395,7 +3395,7 @@
goto unwritable_page;
}
} else
- VM_BUG_ON(!PageLocked(page));
+ VM_BUG_ON_PAGE(!PageLocked(page), page);
page_mkwrite = 1;
}
}