On 4/16/2019 8:13 AM, Leon Romanovsky wrote:
From: Leon Romanovsky <leonro@xxxxxxxxxxxx>
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 <leonro@xxxxxxxxxxxx>
---
drivers/infiniband/sw/rdmavt/ah.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
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--;
We already know of this and are preparing a patch. I don't have a time
estimate but would surely expect it in time for the merge window.
-Denny
