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 <dave.hansen@linux.intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Davidlohr Bueso <davidlohr@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
WARN_ON() and WARN_ON_ONCE(), dependent on CONFIG_DEBUG_VM
Cc: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I tried to use 'dump_page(page, __func__)' for debugging, but it triggers
warning:
warning: passing argument 2 of `dump_page' discards `const' qualifier from pointer target type [enabled by default]
Let's convert 'reason' to 'const char *' in dump_page() and friends: we
shouldn't modify it anyway.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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>
Even if CONFIG_DEBUG_VM=n gcc genereates code for some VM_BUG_ON()
for example VM_BUG_ON(!PageCompound(page) || !PageHead(page)); in
do_huge_pmd_wp_page() generates 114 bytes of code.
But they mostly disappears when I split this VM_BUG_ON into two:
-VM_BUG_ON(!PageCompound(page) || !PageHead(page));
+VM_BUG_ON(!PageCompound(page));
+VM_BUG_ON(!PageHead(page));
weird... but anyway after this patch code disappears completely.
add/remove: 0/0 grow/shrink: 7/97 up/down: 135/-1784 (-1649)
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
No real bugs, just some dead code and some fixups.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
kbuild.h forces include of autoconf.h on the
commandline using -include - so we do not need to
include the file explicit.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Michal Marek <mmarek@suse.cz>
Add some (configurable) expensive sanity checking to catch wrong address
translations on x86.
- create linux/mmdebug.h file to be able include this file in
asm headers to not get unsolvable loops in header files
- __phys_addr on x86_32 became a function in ioremap.c since
PAGE_OFFSET, is_vmalloc_addr and VMALLOC_* non-constasts are undefined
if declared in page_32.h
- add __phys_addr_const for initializing doublefault_tss.__cr3
Tested on 386, 386pae, x86_64 and x86_64 numa=fake=2.
Contains Andi's enable numa virtual address debug patch.
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Dave Hansen