It was fixed upstream. I'm not entirely sure whether 9.10 got this, but
as VMware did not receive any further bug reports I guess it did.
commit 31a5639623a487d6db996c8138c9e53fef2e2d91
Author: Daisuke Nishimura <nishim...@mxp.nes.nec.co.jp>
Date: Mon Sep 21 17:02:50 2009 -0700
mm: add_to_swap_cache() must not sleep
After commit 355cfa73 ("mm: modify swap_map and add SWAP_HAS_CACHE flag"),
read_swap_cache_async() will busy-wait while a entry doesn't exist in swap
cache but it has SWAP_HAS_CACHE flag.
Such entries can exist on add/delete path of swap cache. On add path,
add_to_swap_cache() is called soon after SWAP_HAS_CACHE flag is set, and
on delete path, swapcache_free() will be called (SWAP_HAS_CACHE flag is
cleared) soon after __delete_from_swap_cache() is called. So, the
busy-wait works well in most cases.
But this mechanism can cause soft lockup if add_to_swap_cache() sleeps and
read_swap_cache_async() tries to swap-in the same entry on the same cpu.
This patch calls radix_tree_preload() before swapcache_prepare() and
divides add_to_swap_cache() into two part: radix_tree_preload() part and
radix_tree_insert() part(define it as __add_to_swap_cache()).
Signed-off-by: Daisuke Nishimura <nishim...@mxp.nes.nec.co.jp>
Cc: KAMEZAWA Hiroyuki <kamezawa.hir...@jp.fujitsu.com>
Cc: Balbir Singh <bal...@linux.vnet.ibm.com>
Cc: Hugh Dickins <hugh.dick...@tiscali.co.uk>
Cc: Johannes Weiner <han...@cmpxchg.org>
Signed-off-by: Andrew Morton <a...@linux-foundation.org>
Signed-off-by: Linus Torvalds <torva...@linux-foundation.org>
** Changed in: linux (Ubuntu)
Status: Incomplete => Fix Released
--
Kernel hang under memory stress
https://bugs.launchpad.net/bugs/433646
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