RDMA/uverbs: Don't overwrite NULL pointer with ZERO_SIZE_PTR

Number of specs is provided by user and in valid case can be equal to zero.
Such argument causes to call to kcalloc() with zero-length request and in
return the ZERO_SIZE_PTR is assigned. This pointer is different from NULL
and makes various if (..) checks to success.

Fixes: e58596071643 ("IB/uverbs: Add support for flow counters")
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c
index 74c5bc934822b9782d877b716c10af03fc763c61..7d70d17a853add2540382d611d6004bdac709d09 100644 (file)
--- a/drivers/infiniband/core/uverbs_cmd.c
+++ b/drivers/infiniband/core/uverbs_cmd.c
@@ -2763,6 +2763,9 @@ static struct ib_uflow_resources *flow_resources_alloc(size_t num_specs)
        if (!resources)
                return NULL;
 
+       if (!num_specs)
+               goto out;
+
        resources->counters =
                kcalloc(num_specs, sizeof(*resources->counters), GFP_KERNEL);
        resources->collection =
@@ -2771,8 +2774,8 @@ static struct ib_uflow_resources *flow_resources_alloc(size_t num_specs)
        if (!resources->counters || !resources->collection)
                goto err;
 
+out:
        resources->max = num_specs;
-
        return resources;
 
 err: