5.4-stable review patch. If anyone has any objections, please let me know.
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From: Mahmoud Adam mngyadam@amazon.com
commit 62fc3357e079a07a22465b9b6ef71bb6ea75ee4b upstream.
cp might be null, calling cp->cp_conn would produce null dereference
[Simon Horman adds:]
Analysis:
* cp is a parameter of __rds_rdma_map and is not reassigned.
* The following call-sites pass a NULL cp argument to __rds_rdma_map()
- rds_get_mr() - rds_get_mr_for_dest
* Prior to the code above, the following assumes that cp may be NULL (which is indicative, but could itself be unnecessary)
trans_private = rs->rs_transport->get_mr( sg, nents, rs, &mr->r_key, cp ? cp->cp_conn : NULL, args->vec.addr, args->vec.bytes, need_odp ? ODP_ZEROBASED : ODP_NOT_NEEDED);
* The code modified by this patch is guarded by IS_ERR(trans_private), where trans_private is assigned as per the previous point in this analysis.
The only implementation of get_mr that I could locate is rds_ib_get_mr() which can return an ERR_PTR if the conn (4th) argument is NULL.
* ret is set to PTR_ERR(trans_private). rds_ib_get_mr can return ERR_PTR(-ENODEV) if the conn (4th) argument is NULL. Thus ret may be -ENODEV in which case the code in question will execute.
Conclusion: * cp may be NULL at the point where this patch adds a check; this patch does seem to address a possible bug
Fixes: c055fc00c07b ("net/rds: fix WARNING in rds_conn_connect_if_down") Cc: stable@vger.kernel.org # v4.19+ Signed-off-by: Mahmoud Adam mngyadam@amazon.com Reviewed-by: Simon Horman horms@kernel.org Link: https://lore.kernel.org/r/20240326153132.55580-1-mngyadam@amazon.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/rds/rdma.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/net/rds/rdma.c +++ b/net/rds/rdma.c @@ -280,7 +280,7 @@ static int __rds_rdma_map(struct rds_soc kfree(sg); ret = PTR_ERR(trans_private); /* Trigger connection so that its ready for the next retry */ - if (ret == -ENODEV) + if (ret == -ENODEV && cp) rds_conn_connect_if_down(cp->cp_conn); goto out; }