From: David Miller <davem@davemloft.net>
To: linux-kernel@vger.kernel.org
Cc: iamjoonsoo.kim@lge.com, sparclinux@vger.kernel.org,
hannes@cmpxchg.org, cl@linux.com, penberg@kernel.org,
torvalds@linux-foundation.org
Subject: Re: [PATCH] slab: Fix off by one in object max number tests.
Date: Mon, 05 May 2014 16:57:56 -0400 (EDT) [thread overview]
Message-ID: <20140505.165756.1229178386133288960.davem@davemloft.net> (raw)
In-Reply-To: <20140505.162004.1797345518474659123.davem@davemloft.net>
From: David Miller <davem@davemloft.net>
Date: Mon, 05 May 2014 16:20:04 -0400 (EDT)
>
> 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.
>
> Fixes: a41adfa ("slab: introduce byte sized index for the freelist of a slab")
> Signed-off-by: David S. Miller <davem@davemloft.net>
> ---
>
> 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.
It turns out that after some more testing, I'm still getting spinlock
debugging problems with this fix applied.
The change is still very much correct I think, however.
next prev parent reply other threads:[~2014-05-05 20:57 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-05 20:20 David Miller
2014-05-05 20:57 ` David Miller [this message]
2014-05-05 21:05 ` Sam Ravnborg
2014-05-05 21:08 ` David Miller
2014-05-06 3:25 ` David Miller
2014-05-06 3:32 ` Linus Torvalds
2014-05-06 3:46 ` Linus Torvalds
2014-05-06 3:48 ` David Miller
2014-05-06 4:04 ` Pekka Enberg
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