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: 1e797f556c
("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>
This commit is contained in:
parent
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commit
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@ -3369,11 +3369,11 @@ bool drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
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{
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int ret;
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port = drm_dp_mst_topology_get_port_validated(mgr, port);
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if (!port)
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if (slots < 0)
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return false;
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if (slots < 0)
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port = drm_dp_mst_topology_get_port_validated(mgr, port);
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if (!port)
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return false;
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if (port->vcpi.vcpi > 0) {
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@ -3389,6 +3389,7 @@ bool drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
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if (ret) {
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DRM_DEBUG_KMS("failed to init vcpi slots=%d max=63 ret=%d\n",
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DIV_ROUND_UP(pbn, mgr->pbn_div), ret);
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drm_dp_mst_topology_put_port(port);
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goto out;
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}
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DRM_DEBUG_KMS("initing vcpi for pbn=%d slots=%d\n",
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