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| author | Tobias Jakobi <tjakobi@math.uni-bielefeld.de> | 2024-09-02 12:40:27 +0300 |
|---|---|---|
| committer | Alex Deucher <alexander.deucher@amd.com> | 2024-09-07 00:40:09 +0300 |
| commit | 0607a50c004798a96e62c089a4c34c220179dcb5 (patch) | |
| tree | ce7f60765f918dc5dcedf7bd3992376653eea71b /drivers | |
| parent | a3cc326a43bdc48fbdf53443e1027a03e309b643 (diff) | |
| download | linux-0607a50c004798a96e62c089a4c34c220179dcb5.tar.xz | |
drm/amd/display: Avoid race between dcn35_set_drr() and dc_state_destruct()
dc_state_destruct() nulls the resource context of the DC state. The pipe
context passed to dcn35_set_drr() is a member of this resource context.
If dc_state_destruct() is called parallel to the IRQ processing (which
calls dcn35_set_drr() at some point), we can end up using already nulled
function callback fields of struct stream_resource.
The logic in dcn35_set_drr() already tries to avoid this, by checking tg
against NULL. But if the nulling happens exactly after the NULL check and
before the next access, then we get a race.
Avoid this by copying tg first to a local variable, and then use this
variable for all the operations. This should work, as long as nobody
frees the resource pool where the timing generators live.
Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/3142
Fixes: 06ad7e164256 ("drm/amd/display: Destroy DC context while keeping DML and DML2")
Signed-off-by: Tobias Jakobi <tjakobi@math.uni-bielefeld.de>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/gpu/drm/amd/display/dc/hwss/dcn35/dcn35_hwseq.c | 20 |
1 files changed, 12 insertions, 8 deletions
diff --git a/drivers/gpu/drm/amd/display/dc/hwss/dcn35/dcn35_hwseq.c b/drivers/gpu/drm/amd/display/dc/hwss/dcn35/dcn35_hwseq.c index a4c6decee0f8..5c5b2dd86f58 100644 --- a/drivers/gpu/drm/amd/display/dc/hwss/dcn35/dcn35_hwseq.c +++ b/drivers/gpu/drm/amd/display/dc/hwss/dcn35/dcn35_hwseq.c @@ -1414,7 +1414,13 @@ void dcn35_set_drr(struct pipe_ctx **pipe_ctx, params.vertical_total_mid_frame_num = adjust.v_total_mid_frame_num; for (i = 0; i < num_pipes; i++) { - if ((pipe_ctx[i]->stream_res.tg != NULL) && pipe_ctx[i]->stream_res.tg->funcs) { + /* dc_state_destruct() might null the stream resources, so fetch tg + * here first to avoid a race condition. The lifetime of the pointee + * itself (the timing_generator object) is not a problem here. + */ + struct timing_generator *tg = pipe_ctx[i]->stream_res.tg; + + if ((tg != NULL) && tg->funcs) { if (pipe_ctx[i]->stream && pipe_ctx[i]->stream->ctx->dc->debug.static_screen_wait_frames) { struct dc_crtc_timing *timing = &pipe_ctx[i]->stream->timing; struct dc *dc = pipe_ctx[i]->stream->ctx->dc; @@ -1426,14 +1432,12 @@ void dcn35_set_drr(struct pipe_ctx **pipe_ctx, num_frames = 2 * (frame_rate % 60); } } - if (pipe_ctx[i]->stream_res.tg->funcs->set_drr) - pipe_ctx[i]->stream_res.tg->funcs->set_drr( - pipe_ctx[i]->stream_res.tg, ¶ms); + if (tg->funcs->set_drr) + tg->funcs->set_drr(tg, ¶ms); if (adjust.v_total_max != 0 && adjust.v_total_min != 0) - if (pipe_ctx[i]->stream_res.tg->funcs->set_static_screen_control) - pipe_ctx[i]->stream_res.tg->funcs->set_static_screen_control( - pipe_ctx[i]->stream_res.tg, - event_triggers, num_frames); + if (tg->funcs->set_static_screen_control) + tg->funcs->set_static_screen_control( + tg, event_triggers, num_frames); } } } |