From: David Miller <davem@davemloft.net>
Date: Mon, 5 May 2014 20:20:04 +0000 (-0400)
Subject: slab: Fix off by one in object max number tests.
X-Git-Tag: omap-for-v3.16/fixes-against-rc1~212
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=30321c7b658a5661eea715b33e82a5fd3e33e180;p=pandora-kernel.git

slab: Fix off by one in object max number tests.

If freelist_idx_t is a byte, SLAB_OBJ_MAX_NUM should be 255 not 256, and
likewise if freelist_idx_t is a short, then it should be 65535 not
65536.

This was leading to all kinds of random crashes on sparc64 where
PAGE_SIZE is 8192.  One problem shown was that if spinlock debugging was
enabled, we'd get deadlocks in copy_pte_range() or do_wp_page() with the
same cpu already holding a lock it shouldn't hold, or the lock belonging
to a completely unrelated process.

Fixes: a41adfaa23df ("slab: introduce byte sized index for the freelist of a slab")
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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