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author | Eric Dumazet <eric.dumazet@gmail.com> | 2009-07-23 16:15:34 +0200 |
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committer | Greg Kroah-Hartman <gregkh@suse.de> | 2009-07-30 14:40:29 -0700 |
commit | f95d9271ff0e58fb12fc6f90c13f70d41eee8089 (patch) | |
tree | 2609e36c98ca6c2dc0a740d1cdcf54af17f3c5e5 /drivers/net/ps3_gelic_net.c | |
parent | 7500f93f415a2fc07e0031d99fa3964bf8981cfc (diff) |
nf_conntrack: nf_conntrack_alloc() fixes
commit 941297f443f871b8c3372feccf27a8733f6ce9e9 upstream.
When a slab cache uses SLAB_DESTROY_BY_RCU, we must be careful when allocating
objects, since slab allocator could give a freed object still used by lockless
readers.
In particular, nf_conntrack RCU lookups rely on ct->tuplehash[xxx].hnnode.next
being always valid (ie containing a valid 'nulls' value, or a valid pointer to next
object in hash chain.)
kmem_cache_zalloc() setups object with NULL values, but a NULL value is not valid
for ct->tuplehash[xxx].hnnode.next.
Fix is to call kmem_cache_alloc() and do the zeroing ourself.
As spotted by Patrick, we also need to make sure lookup keys are committed to
memory before setting refcount to 1, or a lockless reader could get a reference
on the old version of the object. Its key re-check could then pass the barrier.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/net/ps3_gelic_net.c')
0 files changed, 0 insertions, 0 deletions