This is a note to let you know that I've just added the patch titled
drm: fix drm_dp_mst_port refcount leaks in drm_dp_mst_allocate_vcpi
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-fix-drm_dp_mst_port-refcount-leaks-in-drm_dp_mst_allocate_vcpi.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From a34a0a632dd991a371fec56431d73279f9c54029 Mon Sep 17 00:00:00 2001
From: Xin Xiong <xiongx18@xxxxxxxxxxxx>
Date: Sun, 19 Jul 2020 23:45:45 +0800
Subject: drm: fix drm_dp_mst_port refcount leaks in drm_dp_mst_allocate_vcpi
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From: Xin Xiong <xiongx18@xxxxxxxxxxxx>
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@xxxxxxxxxxxxxxx> # v4.12+
Signed-off-by: Xiyu Yang <xiyuyang19@xxxxxxxxxxxx>
Signed-off-by: Xin Tan <tanxin.ctf@xxxxxxxxx>
Signed-off-by: Xin Xiong <xiongx18@xxxxxxxxxxxx>
Reviewed-by: Lyude Paul <lyude@xxxxxxxxxx>
Signed-off-by: Lyude Paul <lyude@xxxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20200719154545.GA41231@xin-virtual-machine
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/drm_dp_mst_topology.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -3369,11 +3369,11 @@ bool drm_dp_mst_allocate_vcpi(struct drm
{
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) {
@@ -3389,6 +3389,7 @@ bool drm_dp_mst_allocate_vcpi(struct drm
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",
Patches currently in stable-queue which might be from xiongx18@xxxxxxxxxxxx are
queue-5.4/drm-fix-drm_dp_mst_port-refcount-leaks-in-drm_dp_mst_allocate_vcpi.patch
