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authorXin Xiong <xiongx18@fudan.edu.cn>2020-07-19 18:45:45 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-12-30 13:25:43 +0300
commit88ee1af064560d62df2d419484a96c6b01c0eb71 (patch)
treee443d90716c5a8817409d70e833f06a8ab83e918 /drivers/gpu
parentcb60f048941265ed4d2de82002183e366f2b8a12 (diff)
downloadlinux-88ee1af064560d62df2d419484a96c6b01c0eb71.tar.xz
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 [sudip: use old functions before rename] Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/gpu')
-rw-r--r--drivers/gpu/drm/drm_dp_mst_topology.c7
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 a0aafd9a37e6..c50fe915f5c8 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -2706,11 +2706,11 @@ bool drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
{
int ret;
- port = drm_dp_get_validated_port_ref(mgr, port);
- if (!port)
+ if (slots < 0)
return false;
- if (slots < 0)
+ port = drm_dp_get_validated_port_ref(mgr, port);
+ if (!port)
return false;
if (port->vcpi.vcpi > 0) {
@@ -2725,6 +2725,7 @@ 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_put_port(port);
goto out;
}
DRM_DEBUG_KMS("initing vcpi for pbn=%d slots=%d\n",