Re: Slab corruption in 2.6.16-rc5-mm2

["Jesper Juhl" <jesper.juhl@gmail.com>]

On 3/6/06, Linus Torvalds <torvalds@osdl.org> wrote:
>
> Ok,
>  I have a new favorite suspect.
>
Heh, you are coming up with stuff to test faster than I can build &
boot kernels ;-)
Which is good, we'll get to the bottom of this all the faster :)


> It is this one: commit 4d268eba1187ef66844a6a33b9431e5d0dadd4ad:
>
[--snip--]
>
> Now, maybe I'm just off my rocker again (I've certainly been batting 0.000
> so far, even if I think I've been finding real bugs). So who knows. But I
> get the feeling that that patch is broken.
>
> Either revert it, or try this (TOTALLY UNTESTED!!!) patch..
>
Hmm, that patch doesn't apply at all to 2.6.16-rc5-mm2 :/

patching file mm/slab.c
Hunk #1 FAILED at 1628.
1 out of 1 hunk FAILED -- saving rejects to file mm/slab.c.rej


$ cat mm/slab.c.rej
***************
*** 1628,1649 ****
  			size_t size, size_t align, unsigned long flags)
  {
  	size_t left_over = 0;
- 	int gfporder;

- 	for (gfporder = 0 ; gfporder < MAX_GFP_ORDER; gfporder++) {
  		unsigned int num;
  		size_t remainder;

- 		cache_estimate(gfporder, size, align, flags, &remainder, &num);
  		if (!num)
  			continue;
-
  		/* More than offslab_limit objects will cause problems */
- 		if ((flags & CFLGS_OFF_SLAB) && num > offslab_limit)
  			break;

  		cachep->num = num;
- 		cachep->gfporder = gfporder;
  		left_over = remainder;

  		/*
--- 1628,1652 ----
  			size_t size, size_t align, unsigned long flags)
  {
  	size_t left_over = 0;

+ 	for (;; cachep->gfporder++) {
  		unsigned int num;
  		size_t remainder;

+ 		if (cachep->gfporder > MAX_GFP_ORDER) {
+ 			cachep->num = 0;
+ 			break;
+ 		}
+
+ 		cache_estimate(cachep->gfporder, size, align, flags,
+ 			       &remainder, &num);
  		if (!num)
  			continue;
  		/* More than offslab_limit objects will cause problems */
+ 		if (flags & CFLGS_OFF_SLAB && cachep->num > offslab_limit)
  			break;

  		cachep->num = num;
  		left_over = remainder;

  		/*



> And hey, maybe I'm just crazy.
>
Somehow I don't think that's the core problem here ;)


--
Jesper Juhl <jesper.juhl@gmail.com>
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