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authorPavel Emelyanov <xemul@openvz.org>2008-01-10 03:48:38 -0800
committerDavid S. Miller <davem@davemloft.net>2008-01-10 03:48:38 -0800
commit9cd40029423701c376391da59d2c6469672b4bed (patch)
treea49624a361ab9c28879efc68862aee819538e9bc /net/core/neighbour.c
parentb0de8e402dc5d3ee04f4d0f669ae492a3e569933 (diff)
[NEIGH]: Fix race between neigh_parms_release and neightbl_fill_parms
The neightbl_fill_parms() is called under the write-locked tbl->lock and accesses the parms->dev. The negh_parm_release() calls the dev_put(parms->dev) without this lock. This creates a tiny race window on which the parms contains potentially stale dev pointer. To fix this race it's enough to move the dev_put() upper under the tbl->lock, but note, that the parms are held by neighbors and thus can live after the neigh_parms_release() is called, so we still can have a parm with bad dev pointer. I didn't find where the neigh->parms->dev is accessed, but still think that putting the dev is to be done in a place, where the parms are really freed. Am I right with that? Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/neighbour.c')
-rw-r--r--net/core/neighbour.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 29b8ee4e35d..cc8a2f190ac 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -1316,8 +1316,6 @@ void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms)
*p = parms->next;
parms->dead = 1;
write_unlock_bh(&tbl->lock);
- if (parms->dev)
- dev_put(parms->dev);
call_rcu(&parms->rcu_head, neigh_rcu_free_parms);
return;
}
@@ -1328,6 +1326,8 @@ void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms)
void neigh_parms_destroy(struct neigh_parms *parms)
{
+ if (parms->dev)
+ dev_put(parms->dev);
kfree(parms);
}