diff options
| author | Xin Xiong <xiongx18@fudan.edu.cn> | 2020-07-19 23:45:45 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-08-21 13:07:45 +0200 |
| commit | 65ed6b7dacdb90099ebd50ca79bb72eaaf74a275 (patch) | |
| tree | 7e0e317901f7477f6b7e8a46edd1bc6b41b8c53e | |
| parent | ff4ca77f631ac57013333eecd8ff57e38abb9506 (diff) | |
drm: fix drm_dp_mst_port refcount leaks in drm_dp_mst_allocate_vcpi
commit a34a0a632dd991a371fec56431d73279f9c54029 upstream.
drm_dp_mst_allocate_vcpi() invokes
drm_dp_mst_topology_get_port_validated(), which increases the refcount
of the "port".
These reference counting issues take place in two exception handling
paths separately. Either when “slots” is less than 0 or when
drm_dp_init_vcpi() returns a negative value, the function forgets to
reduce the refcnt increased drm_dp_mst_topology_get_port_validated(),
which results in a refcount leak.
Fix these issues by pulling up the error handling when "slots" is less
than 0, and calling drm_dp_mst_topology_put_port() before termination
when drm_dp_init_vcpi() returns a negative value.
Fixes: 1e797f556c61 ("drm/dp: Split drm_dp_mst_allocate_vcpi")
Cc: <stable@vger.kernel.org> # v4.12+
Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
Signed-off-by: Xin Xiong <xiongx18@fudan.edu.cn>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200719154545.GA41231@xin-virtual-machine
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/gpu/drm/drm_dp_mst_topology.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index a315cc08bb5b..252fc4b56700 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -4319,11 +4319,11 @@ bool drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr *mgr, { int ret; - port = drm_dp_mst_topology_get_port_validated(mgr, port); - if (!port) + if (slots < 0) return false; - if (slots < 0) + port = drm_dp_mst_topology_get_port_validated(mgr, port); + if (!port) return false; if (port->vcpi.vcpi > 0) { @@ -4339,6 +4339,7 @@ bool drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr *mgr, if (ret) { DRM_DEBUG_KMS("failed to init vcpi slots=%d max=63 ret=%d\n", DIV_ROUND_UP(pbn, mgr->pbn_div), ret); + drm_dp_mst_topology_put_port(port); goto out; } DRM_DEBUG_KMS("initing vcpi for pbn=%d slots=%d\n", |