RDMA/mlx4: Do not allow the user to write to the clock page

mlx4_ib_mmap() maps the internal clock page to userspace through
rdma_user_mmap_io(), which does not restrict write access. Userspace can
request PROT_WRITE directly, or upgrade a read-only mapping later with
mprotect() because VM_MAYWRITE remains set.

Reject VM_WRITE, VM_EXEC and clear VM_MAYWRITE, applying the same read-only
policy as commit c660133c339f ("RDMA/mlx5: Do not allow the user to write to the
clock page"). The rdma-core mlx4 provider requests this mapping with
PROT_READ, so its existing behavior is unchanged.

Fixes: 52033cfb5aab ("IB/mlx4: Add mmap call to map the hardware clock")
Signed-off-by: Jiale Yao <yaojiale02@163.com>
Link: https://patch.msgid.link/20260926111150.3197004-1-yaojiale02@163.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>

0 files changed, 0 insertions, 0 deletions