From: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
commit e4f674229ce63dac60be0c4ddfb5ef8d1225d30d upstream
I recently added a patch to let folks pass a "reason" string dump_page()
which gets dumped out along with the page's data. This essentially
saves the bug-reader a trip in to the source to figure out why we
BUG_ON()'d.
The new VM_BUG_ON_PAGE() passes in NULL for "reason". It seems like we
might as well pass the BUG_ON() condition if we have it. This will
bloat kernels a bit with ~160 new strings, but this is all under a
debugging option anyway.
page:ffffea0008560280 count:1 mapcount:0 mapping:(null) index:0x0
page flags: 0xbfffc0000000001(locked)
page dumped because: VM_BUG_ON_PAGE(PageLocked(page))
------------[ cut here ]------------
kernel BUG at /home/davehans/linux.git/mm/filemap.c:464!
invalid opcode: 0000 [#1] SMP
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.14.0+ #251
Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
...
[akpm@xxxxxxxxxxxxxxxxxxxx: include stringify.h]
Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Acked-by: Davidlohr Bueso <davidlohr@xxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
[fixes the conflict and includes the VM_BUG_ON_PAGE]
Signed-off-by: Gavin Guo <gavin.guo@xxxxxxxxxxxxx>
---
include/linux/mmdebug.h | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/include/linux/mmdebug.h b/include/linux/mmdebug.h
index 580bd587d916..fa387ca7218c 100644
--- a/include/linux/mmdebug.h
+++ b/include/linux/mmdebug.h
@@ -1,10 +1,19 @@
#ifndef LINUX_MM_DEBUG_H
#define LINUX_MM_DEBUG_H 1
+#include <linux/stringify.h>
#ifdef CONFIG_DEBUG_VM
#define VM_BUG_ON(cond) BUG_ON(cond)
+#define VM_BUG_ON_PAGE(cond, page) \
+ do { \
+ if (unlikely(cond)) { \
+ dump_page(page, "VM_BUG_ON_PAGE(" __stringify(cond)")");\
+ BUG(); \
+ } \
+ } while (0)
#else
#define VM_BUG_ON(cond) BUILD_BUG_ON_INVALID(cond)
+#define VM_BUG_ON_PAGE(cond, page) VM_BUG_ON(cond)
#endif
#ifdef CONFIG_DEBUG_VIRTUAL
--
2.0.0
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