Subject: + mm-pass-vm_bug_on-reason-to-dump_page.patch added to -mm tree
To: dave.hansen@xxxxxxxxxxxxxxx,davidlohr@xxxxxx,kirill.shutemov@xxxxxxxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Wed, 16 Apr 2014 16:07:49 -0700
The patch titled
Subject: mm: pass VM_BUG_ON() reason to dump_page()
has been added to the -mm tree. Its filename is
mm-pass-vm_bug_on-reason-to-dump_page.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-pass-vm_bug_on-reason-to-dump_page.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-pass-vm_bug_on-reason-to-dump_page.patch
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From: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Subject: mm: pass VM_BUG_ON() reason to dump_page()
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
...
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>
---
include/linux/mmdebug.h | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff -puN include/linux/mmdebug.h~mm-pass-vm_bug_on-reason-to-dump_page include/linux/mmdebug.h
--- a/include/linux/mmdebug.h~mm-pass-vm_bug_on-reason-to-dump_page
+++ a/include/linux/mmdebug.h
@@ -9,8 +9,13 @@ extern void dump_page_badflags(struct pa
#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, NULL); BUG(); } } while (0)
+#define VM_BUG_ON_PAGE(cond, page) \
+ do { \
+ if (unlikely(cond)) { \
+ dump_page(page, "VM_BUG_ON_PAGE(" __stringify(cond)")");\
+ BUG(); \
+ } \
+ } while (0)
#define VM_WARN_ON(cond) WARN_ON(cond)
#define VM_WARN_ON_ONCE(cond) WARN_ON_ONCE(cond)
#else
_
Patches currently in -mm which might be from dave.hansen@xxxxxxxxxxxxxxx are
mm-introduce-do_shared_fault-and-drop-do_fault-fix-fix.patch
mm-pass-vm_bug_on-reason-to-dump_page.patch
mm-pass-vm_bug_on-reason-to-dump_page-fix.patch
do_shared_fault-check-that-mmap_sem-is-held.patch
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