From: Leon Romanovsky <leonro@xxxxxxxxxxxx>
Failure in rereg MR releases UMEM but leaves the MR to be destroyed
by the user. As a result the following scenario may happen:
"create MR -> rereg MR with failure -> call to rereg MR again" and
hit "NULL-ptr deref or user memory access" errors.
Ensure that rereg MR is only performed on a non-dead MR.
Cc: syzkaller <syzkaller@xxxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # 4.5
Fixes: 395a8e4c32ea ("IB/mlx5: Refactoring register MR code")
Reported-by: Noa Osherovich <noaos@xxxxxxxxxxxx>
Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxxxx>
---
drivers/infiniband/hw/mlx5/mr.c | 32 +++++++++++++++++++++++---------
1 file changed, 23 insertions(+), 9 deletions(-)
diff --git a/drivers/infiniband/hw/mlx5/mr.c b/drivers/infiniband/hw/mlx5/mr.c
index 1520a2f20f98..90a9c461cedc 100644
--- a/drivers/infiniband/hw/mlx5/mr.c
+++ b/drivers/infiniband/hw/mlx5/mr.c
@@ -866,25 +866,28 @@ static int mr_umem_get(struct ib_pd *pd, u64 start, u64 length,
int *order)
{
struct mlx5_ib_dev *dev = to_mdev(pd->device);
+ struct ib_umem *u;
int err;
- *umem = ib_umem_get(pd->uobject->context, start, length,
- access_flags, 0);
- err = PTR_ERR_OR_ZERO(*umem);
+ *umem = NULL;
+
+ u = ib_umem_get(pd->uobject->context, start, length, access_flags, 0);
+ err = PTR_ERR_OR_ZERO(u);
if (err) {
- *umem = NULL;
- mlx5_ib_err(dev, "umem get failed (%d)\n", err);
+ mlx5_ib_dbg(dev, "umem get failed (%d)\n", err);
return err;
}
- mlx5_ib_cont_pages(*umem, start, MLX5_MKEY_PAGE_SHIFT_MASK, npages,
+ mlx5_ib_cont_pages(u, start, MLX5_MKEY_PAGE_SHIFT_MASK, npages,
page_shift, ncont, order);
if (!*npages) {
mlx5_ib_warn(dev, "avoid zero region\n");
- ib_umem_release(*umem);
+ ib_umem_release(u);
return -EINVAL;
}
+ *umem = u;
+
mlx5_ib_dbg(dev, "npages %d, ncont %d, order %d, page_shift %d\n",
*npages, *ncont, *order, *page_shift);
@@ -1458,13 +1461,12 @@ int mlx5_ib_rereg_user_mr(struct ib_mr *ib_mr, int flags, u64 start,
int access_flags = flags & IB_MR_REREG_ACCESS ?
new_access_flags :
mr->access_flags;
- u64 addr = (flags & IB_MR_REREG_TRANS) ? virt_addr : mr->umem->address;
- u64 len = (flags & IB_MR_REREG_TRANS) ? length : mr->umem->length;
int page_shift = 0;
int upd_flags = 0;
int npages = 0;
int ncont = 0;
int order = 0;
+ u64 addr, len;
int err;
mlx5_ib_dbg(dev, "start 0x%llx, virt_addr 0x%llx, length 0x%llx, access_flags 0x%x\n",
@@ -1472,6 +1474,17 @@ int mlx5_ib_rereg_user_mr(struct ib_mr *ib_mr, int flags, u64 start,
atomic_sub(mr->npages, &dev->mdev->priv.reg_pages);
+ if (!mr->umem)
+ return -EINVAL;
+
+ if (flags & IB_MR_REREG_TRANS) {
+ addr = virt_addr;
+ len = length;
+ } else {
+ addr = mr->umem->address;
+ len = mr->umem->length;
+ }
+
if (flags != IB_MR_REREG_PD) {
/*
* Replace umem. This needs to be done whether or not UMR is
@@ -1479,6 +1492,7 @@ int mlx5_ib_rereg_user_mr(struct ib_mr *ib_mr, int flags, u64 start,
*/
flags |= IB_MR_REREG_TRANS;
ib_umem_release(mr->umem);
+ mr->umem = NULL;
err = mr_umem_get(pd, addr, len, access_flags, &mr->umem,
&npages, &page_shift, &ncont, &order);
if (err)
--
2.14.3
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