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Date: Mon, 05 Jul 2010 20:58:27 -0700 From: Roland Dreier <rdreier@...co.com> To: Benjamin Herrenschmidt <benh@...nel.crashing.org> Cc: linux-mm@...ck.org, Christoph Lameter <cl@...ux-foundation.org>, "linux-kernel\@vger.kernel.org" <linux-kernel@...r.kernel.org> Subject: Re: kmem_cache_destroy() badness with SLUB Hi folks ! Internally, I'm hitting a little "nit"... sysfs_slab_add() has this check: if (slab_state < SYSFS) /* Defer until later */ return 0; But sysfs_slab_remove() doesn't. So if the slab is created -and- destroyed at, for example, arch_initcall time, then we hit a WARN in the kobject code, trying to dispose of a non-existing kobject. Now, at first sight, just adding the same test to sysfs_slab_remove() would do the job... but it all seems very racy to me. I don't understand in fact how this slab_state deals with races at all. What prevents us from hitting slab_sysfs_init() at the same time as another CPU deos sysfs_slab_add() ? How do that deal with collisions trying to register the same kobject twice ? Similar race with remove... Shouldn't we have a mutex around those guys ? Cheers, Ben. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ -- Roland Dreier <rolandd@...co.com> || For corporate legal information go to: http://www.cisco.com/web/about/doing_business/legal/cri/index.html -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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