From 70096a561d1e09120bae1f293f3632cedbfd5c68 Mon Sep 17 00:00:00 2001
From: Matt Mackall <mpm@selenic.com>
Date: Wed, 8 Oct 2008 14:51:57 -0500
Subject: [PATCH] SLOB: fix bogus ksize calculation fix
This fixes the previous fix, which was completely wrong on closer
inspection. This version has been manually tested with a user-space
test harness and generates sane values. A nearly identical patch has
been boot-tested.
The problem arose from changing how kmalloc/kfree handled alignment
padding without updating ksize to match. This brings it in sync.
Signed-off-by: Matt Mackall <mpm@selenic.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
mm/slob.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/mm/slob.c b/mm/slob.c
index 62b679dc660f..cb675d126791 100644
--- a/mm/slob.c
+++ b/mm/slob.c
@@ -514,9 +514,11 @@ size_t ksize(const void *block)
return 0;
sp = (struct slob_page *)virt_to_page(block);
- if (slob_page(sp))
- return (((slob_t *)block - 1)->units - 1) * SLOB_UNIT;
- else
+ if (slob_page(sp)) {
+ int align = max(ARCH_KMALLOC_MINALIGN, ARCH_SLAB_MINALIGN);
+ unsigned int *m = (unsigned int *)(block - align);
+ return SLOB_UNITS(*m) * SLOB_UNIT;
+ } else
return sp->page.private;
}