6.11-stable review patch. If anyone has any objections, please let me know.
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From: Tobias Jakobi tjakobi@math.uni-bielefeld.de
[ Upstream commit e7d4e1438533abe448813bdc45691f9c230aa307 ]
As set_drr() is called from IRQ context, it can happen that the pipe context has been nulled by dc_state_destruct().
Apply the same protection here that is already present for dcn35_set_drr() and dcn10_set_drr(). I.e. fetch the tg pointer first (to avoid a race with dc_state_destruct()), and then check the local copy before using it.
Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/3142 Fixes: 06ad7e164256 ("drm/amd/display: Destroy DC context while keeping DML and DML2") Acked-by: Alex Deucher alexander.deucher@amd.com Signed-off-by: Tobias Jakobi tjakobi@math.uni-bielefeld.de Signed-off-by: Alex Deucher alexander.deucher@amd.com Signed-off-by: Sasha Levin sashal@kernel.org --- .../amd/display/dc/hwss/dce110/dce110_hwseq.c | 21 ++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-)
diff --git a/drivers/gpu/drm/amd/display/dc/hwss/dce110/dce110_hwseq.c b/drivers/gpu/drm/amd/display/dc/hwss/dce110/dce110_hwseq.c index 4d6e90c49ad53..fc0d2077aaec4 100644 --- a/drivers/gpu/drm/amd/display/dc/hwss/dce110/dce110_hwseq.c +++ b/drivers/gpu/drm/amd/display/dc/hwss/dce110/dce110_hwseq.c @@ -2085,13 +2085,20 @@ static void set_drr(struct pipe_ctx **pipe_ctx, * as well. */ for (i = 0; i < num_pipes; i++) { - pipe_ctx[i]->stream_res.tg->funcs->set_drr( - pipe_ctx[i]->stream_res.tg, ¶ms); - - if (adjust.v_total_max != 0 && adjust.v_total_min != 0) - pipe_ctx[i]->stream_res.tg->funcs->set_static_screen_control( - pipe_ctx[i]->stream_res.tg, - event_triggers, num_frames); + /* 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 (tg->funcs->set_drr) + tg->funcs->set_drr(tg, ¶ms); + if (adjust.v_total_max != 0 && adjust.v_total_min != 0) + if (tg->funcs->set_static_screen_control) + tg->funcs->set_static_screen_control( + tg, event_triggers, num_frames); + } } }