diff options
| author | Lyude Paul <lyude@redhat.com> | 2020-04-06 15:33:52 -0400 |
|---|---|---|
| committer | Lyude Paul <lyude@redhat.com> | 2020-04-06 15:54:00 -0400 |
| commit | cbfb1b74438fdab9ab34a24bb3a206033d807dc0 (patch) | |
| tree | 951c06f45208e615e1c889e4e17ee3cd233761fb /drivers/gpu/drm/drm_dp_mst_topology.c | |
| parent | ed7cca1ff0142b4e24daed94271afef3b9bb4162 (diff) | |
drm/dp_mst: Fix NULL deref in drm_dp_get_one_sb_msg()
While we don't need this function to store an mstb anywhere for UP
requests since we process them asynchronously, we do need to make sure
that we don't try to write to **mstb for UP requests otherwise we'll
cause a NULL pointer deref:
RIP: 0010:drm_dp_get_one_sb_msg+0x4b/0x460 [drm_kms_helper]
Call Trace:
? vprintk_emit+0x16a/0x230
? drm_dp_mst_hpd_irq+0x133/0x1010 [drm_kms_helper]
drm_dp_mst_hpd_irq+0x133/0x1010 [drm_kms_helper]
? __drm_dbg+0x87/0x90 [drm]
? intel_dp_hpd_pulse+0x24b/0x400 [i915]
intel_dp_hpd_pulse+0x24b/0x400 [i915]
i915_digport_work_func+0xd6/0x160 [i915]
process_one_work+0x1a9/0x370
worker_thread+0x4d/0x3a0
kthread+0xf9/0x130
? process_one_work+0x370/0x370
? kthread_park+0x90/0x90
ret_from_fork+0x35/0x40
So, fix this.
Signed-off-by: Lyude Paul <lyude@redhat.com>
Fixes: fbc821c4a506 ("drm/mst: Support simultaneous down replies")
Cc: Wayne Lin <Wayne.Lin@amd.com>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Wayne Lin <waynelin@amd.com>
Cc: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200406193352.1245985-1-lyude@redhat.com
Reviewed-by: Sean Paul <sean@poorly.run>
Diffstat (limited to 'drivers/gpu/drm/drm_dp_mst_topology.c')
| -rw-r--r-- | drivers/gpu/drm/drm_dp_mst_topology.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index 3331de086580..6994076cbdc7 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -3702,7 +3702,8 @@ static bool drm_dp_get_one_sb_msg(struct drm_dp_mst_topology_mgr *mgr, bool up, int basereg = up ? DP_SIDEBAND_MSG_UP_REQ_BASE : DP_SIDEBAND_MSG_DOWN_REP_BASE; - *mstb = NULL; + if (!up) + *mstb = NULL; *seqno = -1; len = min(mgr->max_dpcd_transaction_bytes, 16); |