• Wengang Wang's avatar
    rds: rds_ib_device.refcount overflow · 037177a8
    Wengang Wang authored
    commit 4fabb594 upstream.
    
    Fixes: 3e0249f9 ("RDS/IB: add refcount tracking to struct rds_ib_device")
    
    There lacks a dropping on rds_ib_device.refcount in case rds_ib_alloc_fmr
    failed(mr pool running out). this lead to the refcount overflow.
    
    A complain in line 117(see following) is seen. From vmcore:
    s_ib_rdma_mr_pool_depleted is 2147485544 and rds_ibdev->refcount is -2147475448.
    That is the evidence the mr pool is used up. so rds_ib_alloc_fmr is very likely
    to return ERR_PTR(-EAGAIN).
    
    115 void rds_ib_dev_put(struct rds_ib_device *rds_ibdev)
    116 {
    117         BUG_ON(atomic_read(&rds_ibdev->refcount) <= 0);
    118         if (atomic_dec_and_test(&rds_ibdev->refcount))
    119                 queue_work(rds_wq, &rds_ibdev->free_work);
    120 }
    
    fix is to drop refcount when rds_ib_alloc_fmr failed.
    Signed-off-by: default avatarWengang Wang <wen.gang.wang@oracle.com>
    Reviewed-by: default avatarHaggai Eran <haggaie@mellanox.com>
    Signed-off-by: default avatarDoug Ledford <dledford@redhat.com>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    037177a8
ib_rdma.c 19.7 KB