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Date: Thu, 9 Oct 2014 22:24:49 -0700
From: Eric Dumazet <edumazet@...gle.com>
To: "David S. Miller" <davem@...emloft.net>
Cc: netdev@...r.kernel.org,
Alexander Duyck <alexander.h.duyck@...hat.com>,
Andres Lagar-Cavilla <andreslc@...gle.com>,
Greg Thelen <gthelen@...gle.com>,
Hugh Dickins <hughd@...gle.com>,
David Rientjes <rientjes@...gle.com>,
Eric Dumazet <edumazet@...gle.com>
Subject: [PATCH net 0/5] net: fix races accessing page->_count
This is illegal to use atomic_set(&page->_count, ...) even if we 'own'
the page. Other entities in the kernel need to use get_page_unless_zero()
to get a reference to the page before testing page properties, so we could
loose a refcount increment.
The only case it is valid is when page->_count is 0, we can use this in
__netdev_alloc_frag()
Note that I never seen crashes caused by these races, the issue was reported
by Andres Lagar-Cavilla and Hugh Dickins.
Eric Dumazet (5):
fm10k: fix race accessing page->_count
igb: fix race accessing page->_count
igb: fix race accessing page->_count
mlx4: fix race accessing page->_count
net: fix races in page->_count manipulation
drivers/net/ethernet/intel/fm10k/fm10k_main.c | 7 +++----
drivers/net/ethernet/intel/igb/igb_main.c | 7 +++----
drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 8 +++-----
drivers/net/ethernet/mellanox/mlx4/en_rx.c | 6 +++---
net/core/skbuff.c | 25 ++++++++++++++++++-------
5 files changed, 30 insertions(+), 23 deletions(-)
--
2.1.0.rc2.206.gedb03e5
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