From e4f674229ce63dac60be0c4ddfb5ef8d1225d30d Mon Sep 17 00:00:00 2001 From: Dave Hansen Date: Wed, 4 Jun 2014 16:07:02 -0700 Subject: [PATCH] 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 ... [akpm@linux-foundation.org: include stringify.h] Signed-off-by: Dave Hansen Acked-by: Kirill A. Shutemov Acked-by: Davidlohr Bueso Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/mmdebug.h | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/include/linux/mmdebug.h b/include/linux/mmdebug.h index a3499d7b0e8a..edd82a105220 100644 --- a/include/linux/mmdebug.h +++ b/include/linux/mmdebug.h @@ -1,6 +1,8 @@ #ifndef LINUX_MM_DEBUG_H #define LINUX_MM_DEBUG_H 1 +#include + struct page; extern void dump_page(struct page *page, const char *reason); @@ -9,8 +11,13 @@ extern void dump_page_badflags(struct page *page, const char *reason, #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 -- 2.39.2