Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider: - [High] The patch introduces a Time-of-Check to Time-of-Use (TOCTOU) race by splitting a single `sink_count` evaluation into two unprotected checks, risking an inconsistent hardware disable sequence. --
commit 4b86b22d6f1aa41eba1cece8a907cf0b3a12b55c Author: Yongxing Mou <[email protected]> drm/msm/dp: simplify link and clock disable sequence This patch refactors the disable sequence by pulling common steps out of the sink_count condition block to simplify the flow. > diff --git a/drivers/gpu/drm/msm/dp/dp_display.c > b/drivers/gpu/drm/msm/dp/dp_display.c > --- a/drivers/gpu/drm/msm/dp/dp_display.c > +++ b/drivers/gpu/drm/msm/dp/dp_display.c [ ... ] > @@ -716,27 +716,19 @@ static int msm_dp_display_disable(struct > msm_dp_display_private *dp) > > msm_dp_panel_disable_vsc_sdp(dp->panel); > > - /* dongle is still connected but sinks are disconnected */ > - if (dp->link->sink_count == 0) { [ ... ] > + msm_dp_ctrl_off_pixel_clk(dp->ctrl); > > - /* set dongle to D3 (power off) mode */ > + /* dongle is still connected but sinks are disconnected */ > + if (dp->link->sink_count == 0) > msm_dp_link_psm_config(dp->link, &dp->panel->link_info, true); > - msm_dp_ctrl_off_pixel_clk(dp->ctrl); > - msm_dp_ctrl_off_link(dp->ctrl, dp->panel); > + > + msm_dp_ctrl_off_link(dp->ctrl, dp->panel); > + > + if (dp->link->sink_count == 0) [Severity: High] Could this double-evaluation of dp->link->sink_count introduce a race condition? The original code checked dp->link->sink_count == 0 exactly once. By checking it twice, if an asynchronously processed HPD IRQ event modifies the sink_count between the two checks, could the driver execute a mismatched hardware disable sequence? For instance, if sink_count changes from 0 to 1 after the first check, the driver would perform msm_dp_link_psm_config(), but then take the else branch and call msm_dp_display_host_phy_exit() below. This would leave the PHY completely powered down, potentially breaking the ability to detect future dongle disconnects. Would it be safer to read sink_count once into a local variable and evaluate the local variable for both conditions? > + /* re-init the PHY so that we can listen to Dongle disconnect */ > msm_dp_ctrl_reinit_phy(dp->ctrl); > - } else { > - /* > - * unplugged interrupt > - * dongle unplugged out of DUT > - */ > - msm_dp_ctrl_off_pixel_clk(dp->ctrl); > - msm_dp_ctrl_off_link(dp->ctrl, dp->panel); > + else > msm_dp_display_host_phy_exit(dp); > - } > > msm_dp_display->power_on = false; -- Sashiko AI review ยท https://sashiko.dev/#/patchset/[email protected]?part=12
