IB/uverbs: Fix kernel crash during MR deregistration flow

This patch fixes a crash that happens due to access to an
uninitialized DM pointer within the MR object.

The change makes sure the DM pointer in the MR object is set to
NULL during a non-DM MR creation to prevent a false indication
that this MR is related to a DM in the dereg flow.

Fixes: be934cca9e98 ("IB/uverbs: Add device memory registration ioctl support")
Reported-by: Lijun Ou <oulijun@huawei.com>
Signed-off-by: Ariel Levkovich <lariel@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c
index 1837924..21a887c 100644 (file)
--- a/drivers/infiniband/core/uverbs_cmd.c
+++ b/drivers/infiniband/core/uverbs_cmd.c
@@ -691,6 +691,7 @@ ssize_t ib_uverbs_reg_mr(struct ib_uverbs_file *file,
 
        mr->device  = pd->device;
        mr->pd      = pd;
+       mr->dm      = NULL;
        mr->uobject = uobj;
        atomic_inc(&pd->usecnt);
        mr->res.type = RDMA_RESTRACK_MR;

diff --git a/drivers/infiniband/core/verbs.c b/drivers/infiniband/core/verbs.c
index 7eff3ae..6ddfb1f 100644 (file)
--- a/drivers/infiniband/core/verbs.c
+++ b/drivers/infiniband/core/verbs.c
@@ -1656,6 +1656,7 @@ struct ib_mr *ib_alloc_mr(struct ib_pd *pd,
        if (!IS_ERR(mr)) {
                mr->device  = pd->device;
                mr->pd      = pd;
+               mr->dm      = NULL;
                mr->uobject = NULL;
                atomic_inc(&pd->usecnt);
                mr->need_inval = false;