allocate_usb4_bandwidth_for_stream() and allocate_usb4_bandwidth() both
use ASSERT(stream->sink) before dereferencing stream->sink->link. ASSERT
is compiled out in production builds, so a NULL stream->sink causes a
NULL pointer dereference.
link_set_dpms_off() already guards two earlier accesses to stream->sink
with explicit NULL checks, confirming that stream->sink can legitimately
be NULL. The subsequent call to deallocate_usb4_bandwidth() had no
equivalent guard.
Replace the ASSERT() calls with proper NULL checks that return false
early, and add a matching stream->sink guard at the call site in
link_set_dpms_off() consistent with the surrounding pattern.
v2: Keep the existing ASSERT() calls for diagnostics (to report
unexpected NULL sink), and add explicit NULL checks that return false
before dereferencing stream->sink. Also add a matching stream->sink
guard at the deallocation call site in link_set_dpms_off(). (Alex)
Fixes: 06ab8d420454 ("drm/amd/display: Remove sink usage from DPMS")
Reported-by: Dan Carpenter <[email protected]>
Cc: Nicholas Kazlauskas <[email protected]>
Cc: Dominik Kaszewski <[email protected]>
Cc: George Zhang <[email protected]>
Cc: Aurabindo Pillai <[email protected]>
Cc: Roman Li <[email protected]>
Cc: Ivan Lipski <[email protected]>
Cc: Dan Wheeler <[email protected]>
Cc: Alex Hung <[email protected]>
Cc: Tom Chung <[email protected]>
Signed-off-by: Srinivasan Shanmugam <[email protected]>
---
.../gpu/drm/amd/display/dc/link/link_dpms.c | 18 ++++++++++++++----
1 file changed, 14 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/amd/display/dc/link/link_dpms.c
b/drivers/gpu/drm/amd/display/dc/link/link_dpms.c
index 48b086d15ab0..25ec3d38a14e 100644
--- a/drivers/gpu/drm/amd/display/dc/link/link_dpms.c
+++ b/drivers/gpu/drm/amd/display/dc/link/link_dpms.c
@@ -2306,9 +2306,14 @@ static bool allocate_usb4_bandwidth_for_stream(struct
dc_stream_state *stream, i
{
ASSERT(stream->sink);
- struct dc_link *link = stream->sink->link;
+ struct dc_link *link;
int req_bw = stream_bw;
+ if (!stream->sink)
+ return false;
+
+ link = stream->sink->link;
+
DC_LOGGER_INIT(link->ctx->logger);
if (!link->dpia_bw_alloc_config.bw_alloc_enabled)
@@ -2355,9 +2360,13 @@ static bool allocate_usb4_bandwidth(struct
dc_stream_state *stream)
ASSERT(stream->sink);
bool ret;
+ int bw;
- int bw = dc_bandwidth_in_kbps_from_timing(&stream->timing,
-
dc_link_get_highest_encoding_format(stream->sink->link));
+ if (!stream->sink)
+ return false;
+
+ bw = dc_bandwidth_in_kbps_from_timing(&stream->timing,
+
dc_link_get_highest_encoding_format(stream->sink->link));
ret = allocate_usb4_bandwidth_for_stream(stream, bw);
@@ -2419,7 +2428,8 @@ enum dc_status link_set_dpms_off(struct pipe_ctx
*pipe_ctx)
update_psp_stream_config(pipe_ctx, true);
dc->hwss.blank_stream(pipe_ctx);
- if
(pipe_ctx->link_config.dp_tunnel_settings.should_use_dp_bw_allocation)
+ if
(pipe_ctx->link_config.dp_tunnel_settings.should_use_dp_bw_allocation &&
+ stream->sink)
deallocate_usb4_bandwidth(stream);
if (stream->signal == SIGNAL_TYPE_DISPLAY_PORT_MST)
--
2.34.1
