From: "Siddha, Suresh B" <suresh.b.siddha@intel.com>
To: torvalds@linux-foundation.org, clameter@sgi.com,
akpm@linux-foundation.org, ak@suse.de
Cc: linux-kernel@vger.kernel.org, tony.luck@intel.com,
asit.k.mallick@intel.com
Subject: x86_64: potential critical issue with quicklists and page table pages
Date: Fri, 21 Sep 2007 11:07:42 -0700 [thread overview]
Message-ID: <20070921180742.GH20863@linux-os.sc.intel.com> (raw)
git commit 34feb2c83beb3bdf13535a36770f7e50b47ef299 started using quicklists
for freeing page table pages and removed the usage of tlb_remove_page()
And looking at quicklist_free() and quicklist_free_page(), on a NUMA platform,
this can potentially free the page before the corresponding TLB caches
are flushed.
Essentially quicklist free routines are doing something like
__quicklist_free()
...
if (unlikely(nid != numa_node_id())) {
__free_page(page);
...
}
....
Now this will potentially cause a problem, if a cpu in someother node starts
using this page, while the corresponding TLB entries are still alive
in the original cpu which is still freeing the page table pages.
This violates the guideline documented in
http://developer.intel.com/design/processor/applnots/317080.pdf
This potentially can cause SW failures and hard to debug issues like
http://www.ussg.iu.edu/hypermail/linux/kernel/0205.2/1254.html
Can we revert this commit for 2.6.23 and look at this code post 2.6.23?
thanks,
suresh
next reply other threads:[~2007-09-21 18:07 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-09-21 18:07 Siddha, Suresh B [this message]
2007-09-21 18:18 ` x86_64: potential critical issue with quicklists and page table pages Andi Kleen
2007-09-21 18:48 ` Linus Torvalds
2007-09-21 18:50 ` Christoph Lameter
2007-09-21 18:55 ` Linus Torvalds
2007-09-21 19:05 ` Linus Torvalds
2007-09-21 19:07 ` Christoph Lameter
2007-09-21 19:21 ` Linus Torvalds
2007-09-21 19:26 ` Christoph Lameter
2007-09-21 19:40 ` Linus Torvalds
2007-09-21 19:44 ` Linus Torvalds
2007-09-21 19:56 ` Christoph Lameter
2007-09-21 19:59 ` Luck, Tony
2007-09-21 20:15 ` Christoph Lameter
2007-09-24 21:27 ` Benjamin Herrenschmidt
2007-09-24 21:42 ` Christoph Lameter
2007-09-25 0:09 ` Benjamin Herrenschmidt
2007-09-21 18:48 ` Christoph Lameter
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