1. 29 Apr, 2016 3 commits
  2. 24 Apr, 2016 2 commits
  3. 23 Apr, 2016 10 commits
  4. 22 Apr, 2016 24 commits
  5. 21 Apr, 2016 1 commit
    • cpaul@redhat.com's avatar
      drm/dp/mst: Validate port in drm_dp_payload_send_msg() · deba0a2a
      cpaul@redhat.com authored
      With the joys of things running concurrently, there's always a chance
      that the port we get passed in drm_dp_payload_send_msg() isn't actually
      valid anymore. Because of this, we need to make sure we validate the
      reference to the port before we use it otherwise we risk running into
      various race conditions. For instance, on the Dell MST monitor I have
      here for testing, hotplugging it enough times causes us to kernel panic:
      
      [drm:intel_mst_enable_dp] 1
      [drm:drm_dp_update_payload_part2] payload 0 1
      [drm:intel_get_hpd_pins] hotplug event received, stat 0x00200000, dig 0x10101011, pins 0x00000020
      [drm:intel_hpd_irq_handler] digital hpd port B - short
      [drm:intel_dp_hpd_pulse] got hpd irq on port B - short
      [drm:intel_dp_check_mst_status] got esi 00 10 00
      [drm:drm_dp_update_payload_part2] payload 1 1
      general protection fault: 0000 [#1] SMP
      …
      Call Trace:
       [<ffffffffa012b632>] drm_dp_update_payload_part2+0xc2/0x130 [drm_kms_helper]
       [<ffffffffa032ef08>] intel_mst_enable_dp+0xf8/0x180 [i915]
       [<ffffffffa0310dbd>] haswell_crtc_enable+0x3ed/0x8c0 [i915]
       [<ffffffffa030c84d>] intel_atomic_commit+0x5ad/0x1590 [i915]
       [<ffffffffa01db877>] ? drm_atomic_set_crtc_for_connector+0x57/0xe0 [drm]
       [<ffffffffa01dc4e7>] drm_atomic_commit+0x37/0x60 [drm]
       [<ffffffffa0130a3a>] drm_atomic_helper_set_config+0x7a/0xb0 [drm_kms_helper]
       [<ffffffffa01cc482>] drm_mode_set_config_internal+0x62/0x100 [drm]
       [<ffffffffa01d02ad>] drm_mode_setcrtc+0x3cd/0x4e0 [drm]
       [<ffffffffa01c18e3>] drm_ioctl+0x143/0x510 [drm]
       [<ffffffffa01cfee0>] ? drm_mode_setplane+0x1b0/0x1b0 [drm]
       [<ffffffff810f79a7>] ? hrtimer_start_range_ns+0x1b7/0x3a0
       [<ffffffff81212962>] do_vfs_ioctl+0x92/0x570
       [<ffffffff81590852>] ? __sys_recvmsg+0x42/0x80
       [<ffffffff81212eb9>] SyS_ioctl+0x79/0x90
       [<ffffffff816b4e32>] entry_SYSCALL_64_fastpath+0x1a/0xa4
      RIP  [<ffffffffa012b026>] drm_dp_payload_send_msg+0x146/0x1f0 [drm_kms_helper]
      
      Which occurs because of the hotplug event shown in the log, which ends
      up causing DRM's dp helpers to drop the port we're updating the payload
      on and panic.
      
      CC: stable@vger.kernel.org
      Signed-off-by: default avatarLyude <cpaul@redhat.com>
      Reviewed-by: default avatarDavid Airlie <airlied@linux.ie>
      Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
      deba0a2a