diff options
| author | Tobias Jakobi <tjakobi@math.uni-bielefeld.de> | 2024-09-02 11:40:26 +0200 |
|---|---|---|
| committer | Alex Deucher <alexander.deucher@amd.com> | 2024-09-10 16:15:59 -0400 |
| commit | a7aeb03888b92304e2fc7d4d1c242f54a312561b (patch) | |
| tree | 8a034a95d392515547697647e4394d9e1098ac1f | |
| parent | 02c132166993c8f8ca1b319665181f72f22ebc6b (diff) | |
drm/amd/display: Avoid race between dcn10_set_drr() and dc_state_destruct()
dc_state_destruct() nulls the resource context of the DC state. The pipe
context passed to dcn10_set_drr() is a member of this resource context.
If dc_state_destruct() is called parallel to the IRQ processing (which
calls dcn10_set_drr() at some point), we can end up using already nulled
function callback fields of struct stream_resource.
The logic in dcn10_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>
Tested-by: Raoul van Rüschen <raoul.van.rueschen@gmail.com>
Tested-by: Christopher Snowhill <chris@kode54.net>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Tested-by: Sefa Eyeoglu <contact@scrumplex.net>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit a3cc326a43bdc48fbdf53443e1027a03e309b643)
Cc: stable@vger.kernel.org
| -rw-r--r-- | drivers/gpu/drm/amd/display/dc/hwss/dcn10/dcn10_hwseq.c | 20 |
1 files changed, 12 insertions, 8 deletions
diff --git a/drivers/gpu/drm/amd/display/dc/hwss/dcn10/dcn10_hwseq.c b/drivers/gpu/drm/amd/display/dc/hwss/dcn10/dcn10_hwseq.c index 14a902ff3b8a..1d2be574f668 100644 --- a/drivers/gpu/drm/amd/display/dc/hwss/dcn10/dcn10_hwseq.c +++ b/drivers/gpu/drm/amd/display/dc/hwss/dcn10/dcn10_hwseq.c @@ -3207,15 +3207,19 @@ void dcn10_set_drr(struct pipe_ctx **pipe_ctx, * as well. */ for (i = 0; i < num_pipes; i++) { - if ((pipe_ctx[i]->stream_res.tg != NULL) && pipe_ctx[i]->stream_res.tg->funcs) { - 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); + /* 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 (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); } } } |