From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Wed, 17 Nov 2010 03:26:42 +0000 (-0800)
Subject: ixgbe: delay rx_ring freeing
X-Git-Tag: v2.6.38-rc1~476^2~547^2~47
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1a51502bddca7ac1e921d918b741ffd2bec149ed;p=pandora-kernel.git

ixgbe: delay rx_ring freeing

"cat /proc/net/dev" uses RCU protection only.

Its quite possible we call a driver get_stats() method while device is
dismantling and freeing its data structures.

So get_stats() methods must be very careful not accessing driver private
data without appropriate locking.

In ixgbe case, we access rx_ring pointers. These pointers are freed in
ixgbe_clear_interrupt_scheme() and set to NULL, this can trigger NULL
dereference in ixgbe_get_stats64()

A possible fix is to use RCU locking in ixgbe_get_stats64() and defer
rx_ring freeing after a grace period in ixgbe_clear_interrupt_scheme()

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Reported-by: Tantilov, Emil S <emil.s.tantilov@intel.com>
Tested-by: Ross Brattain <ross.b.brattain@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
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