From 3a4ef2e2b5cf9a34bcc66c0d33f7eba180a14535 Mon Sep 17 00:00:00 2001 From: Leon Romanovsky Date: Tue, 16 Apr 2019 15:13:10 +0300 Subject: RDMA/rdmavt: Catch use-after-free access of AH structures Prior to commit d345691471b4 ("RDMA: Handle AH allocations by IB/core"), AH destroy path is rdmavt returned -EBUSY warning to application and caused to potential leakage of kernel memory of AH structure. After that commit, the AH structure is always freed but such early return in driver code can potentially cause to use-after-free error. Add warning to catch such situation to help driver developers to fix AH release path. Signed-off-by: Leon Romanovsky Signed-off-by: Jason Gunthorpe --- drivers/infiniband/sw/rdmavt/ah.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'drivers/infiniband') diff --git a/drivers/infiniband/sw/rdmavt/ah.c b/drivers/infiniband/sw/rdmavt/ah.c index e6f7e4689d4d..0e147b32cbe9 100644 --- a/drivers/infiniband/sw/rdmavt/ah.c +++ b/drivers/infiniband/sw/rdmavt/ah.c @@ -141,8 +141,7 @@ void rvt_destroy_ah(struct ib_ah *ibah, u32 destroy_flags) struct rvt_ah *ah = ibah_to_rvtah(ibah); unsigned long flags; - if (atomic_read(&ah->refcount) != 0) - return; + WARN_ON_ONCE(atomic_read(&ah->refcount)); spin_lock_irqsave(&dev->n_ahs_lock, flags); dev->n_ahs_allocated--; -- cgit v1.2.3-59-g8ed1b