aboutsummaryrefslogtreecommitdiff
path: root/CREDITS
diff options
context:
space:
mode:
authorRoland Dreier <rolandd@cisco.com>2006-05-09 10:50:29 -0700
committerRoland Dreier <rolandd@cisco.com>2006-05-09 10:50:29 -0700
commita3285aa4eecd722508dab01c4932b11b4ba80134 (patch)
tree1d12d6bbba7f42939536ccdba14f7738f2a26793 /CREDITS
parentd945e1df28ca07642b3e1a9b9d07074ba5f76be0 (diff)
IB/mthca: Fix race in reference counting
Fix races in in destroying various objects. If a destroy routine waits for an object to become free by doing wait_event(&obj->wait, !atomic_read(&obj->refcount)); /* now clean up and destroy the object */ and another place drops a reference to the object by doing if (atomic_dec_and_test(&obj->refcount)) wake_up(&obj->wait); then this is susceptible to a race where the wait_event() and final freeing of the object occur between the atomic_dec_and_test() and the wake_up(). And this is a use-after-free, since wake_up() will be called on part of the already-freed object. Fix this in mthca by replacing the atomic_t refcounts with plain old integers protected by a spinlock. This makes it possible to do the decrement of the reference count and the wake_up() so that it appears as a single atomic operation to the code waiting on the wait queue. While touching this code, also simplify mthca_cq_clean(): the CQ being cleaned cannot go away, because it still has a QP attached to it. So there's no reason to be paranoid and look up the CQ by number; it's perfectly safe to use the pointer that the callers already have. Signed-off-by: Roland Dreier <rolandd@cisco.com>
Diffstat (limited to 'CREDITS')
0 files changed, 0 insertions, 0 deletions