{
   "containers": {
      "cna": {
         "providerMetadata": {
            "orgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038"
         },
         "descriptions": [
            {
               "lang": "en",
               "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/vc4: don't check if plane->state->fb == state->fb\n\nCurrently, when using non-blocking commits, we can see the following\nkernel warning:\n\n[  110.908514] ------------[ cut here ]------------\n[  110.908529] refcount_t: underflow; use-after-free.\n[  110.908620] WARNING: CPU: 0 PID: 1866 at lib/refcount.c:87 refcount_dec_not_one+0xb8/0xc0\n[  110.908664] Modules linked in: rfcomm snd_seq_dummy snd_hrtimer snd_seq snd_seq_device cmac algif_hash aes_arm64 aes_generic algif_skcipher af_alg bnep hid_logitech_hidpp vc4 brcmfmac hci_uart btbcm brcmutil bluetooth snd_soc_hdmi_codec cfg80211 cec drm_display_helper drm_dma_helper drm_kms_helper snd_soc_core snd_compress snd_pcm_dmaengine fb_sys_fops sysimgblt syscopyarea sysfillrect raspberrypi_hwmon ecdh_generic ecc rfkill libaes i2c_bcm2835 binfmt_misc joydev snd_bcm2835(C) bcm2835_codec(C) bcm2835_isp(C) v4l2_mem2mem videobuf2_dma_contig snd_pcm bcm2835_v4l2(C) raspberrypi_gpiomem bcm2835_mmal_vchiq(C) videobuf2_v4l2 snd_timer videobuf2_vmalloc videobuf2_memops videobuf2_common snd videodev vc_sm_cma(C) mc hid_logitech_dj uio_pdrv_genirq uio i2c_dev drm fuse dm_mod drm_panel_orientation_quirks backlight ip_tables x_tables ipv6\n[  110.909086] CPU: 0 PID: 1866 Comm: kodi.bin Tainted: G         C         6.1.66-v8+ #32\n[  110.909104] Hardware name: Raspberry Pi 3 Model B Rev 1.2 (DT)\n[  110.909114] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)\n[  110.909132] pc : refcount_dec_not_one+0xb8/0xc0\n[  110.909152] lr : refcount_dec_not_one+0xb4/0xc0\n[  110.909170] sp : ffffffc00913b9c0\n[  110.909177] x29: ffffffc00913b9c0 x28: 000000556969bbb0 x27: 000000556990df60\n[  110.909205] x26: 0000000000000002 x25: 0000000000000004 x24: ffffff8004448480\n[  110.909230] x23: ffffff800570b500 x22: ffffff802e03a7bc x21: ffffffecfca68c78\n[  110.909257] x20: ffffff8002b42000 x19: ffffff802e03a600 x18: 0000000000000000\n[  110.909283] x17: 0000000000000011 x16: ffffffffffffffff x15: 0000000000000004\n[  110.909308] x14: 0000000000000fff x13: ffffffed577e47e0 x12: 0000000000000003\n[  110.909333] x11: 0000000000000000 x10: 0000000000000027 x9 : c912d0d083728c00\n[  110.909359] x8 : c912d0d083728c00 x7 : 65646e75203a745f x6 : 746e756f63666572\n[  110.909384] x5 : ffffffed579f62ee x4 : ffffffed579eb01e x3 : 0000000000000000\n[  110.909409] x2 : 0000000000000000 x1 : ffffffc00913b750 x0 : 0000000000000001\n[  110.909434] Call trace:\n[  110.909441]  refcount_dec_not_one+0xb8/0xc0\n[  110.909461]  vc4_bo_dec_usecnt+0x4c/0x1b0 [vc4]\n[  110.909903]  vc4_cleanup_fb+0x44/0x50 [vc4]\n[  110.910315]  drm_atomic_helper_cleanup_planes+0x88/0xa4 [drm_kms_helper]\n[  110.910669]  vc4_atomic_commit_tail+0x390/0x9dc [vc4]\n[  110.911079]  commit_tail+0xb0/0x164 [drm_kms_helper]\n[  110.911397]  drm_atomic_helper_commit+0x1d0/0x1f0 [drm_kms_helper]\n[  110.911716]  drm_atomic_commit+0xb0/0xdc [drm]\n[  110.912569]  drm_mode_atomic_ioctl+0x348/0x4b8 [drm]\n[  110.913330]  drm_ioctl_kernel+0xec/0x15c [drm]\n[  110.914091]  drm_ioctl+0x24c/0x3b0 [drm]\n[  110.914850]  __arm64_sys_ioctl+0x9c/0xd4\n[  110.914873]  invoke_syscall+0x4c/0x114\n[  110.914897]  el0_svc_common+0xd0/0x118\n[  110.914917]  do_el0_svc+0x38/0xd0\n[  110.914936]  el0_svc+0x30/0x8c\n[  110.914958]  el0t_64_sync_handler+0x84/0xf0\n[  110.914979]  el0t_64_sync+0x18c/0x190\n[  110.914996] ---[ end trace 0000000000000000 ]---\n\nThis happens because, although `prepare_fb` and `cleanup_fb` are\nperfectly balanced, we cannot guarantee consistency in the check\nplane->state->fb == state->fb. This means that sometimes we can increase\nthe refcount in `prepare_fb` and don't decrease it in `cleanup_fb`. The\nopposite can also be true.\n\nIn fact, the struct drm_plane .state shouldn't be accessed directly\nbut instead, the `drm_atomic_get_new_plane_state()` helper function should\nbe used. So, we could stick to this check, but using\n`drm_atomic_get_new_plane_state()`. But actually, this check is not re\n---truncated---"
            }
         ],
         "affected": [
            {
               "product": "Linux",
               "vendor": "Linux",
               "defaultStatus": "unaffected",
               "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
               "programFiles": [
                  "drivers/gpu/drm/vc4/vc4_plane.c"
               ],
               "versions": [
                  {
                     "version": "1da177e4c3f4",
                     "lessThan": "48bfb4b03c5f",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "1da177e4c3f4",
                     "lessThan": "d6b2fe2db1d0",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "1da177e4c3f4",
                     "lessThan": "5343f724c912",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "1da177e4c3f4",
                     "lessThan": "5ee0d47dcf33",
                     "status": "affected",
                     "versionType": "git"
                  }
               ]
            },
            {
               "product": "Linux",
               "vendor": "Linux",
               "defaultStatus": "affected",
               "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
               "programFiles": [
                  "drivers/gpu/drm/vc4/vc4_plane.c"
               ],
               "versions": [
                  {
                     "version": "6.1.86",
                     "lessThanOrEqual": "6.1.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "6.6.27",
                     "lessThanOrEqual": "6.6.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "6.8.6",
                     "lessThanOrEqual": "6.8.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "6.9",
                     "lessThanOrEqual": "*",
                     "status": "unaffected",
                     "versionType": "original_commit_for_fix"
                  }
               ]
            }
         ],
         "references": [
            {
               "url": "https://git.kernel.org/stable/c/48bfb4b03c5ff6e1fa1dc73fb915e150b0968c40"
            },
            {
               "url": "https://git.kernel.org/stable/c/d6b2fe2db1d0927b2d7df5c763eba55d0e1def3c"
            },
            {
               "url": "https://git.kernel.org/stable/c/5343f724c912c77541029123f47ecd3d2ea63bdd"
            },
            {
               "url": "https://git.kernel.org/stable/c/5ee0d47dcf33efd8950b347dcf4d20bab12a3fa9"
            }
         ],
         "title": "drm/vc4: don't check if plane->state->fb == state->fb",
         "x_generator": {
            "engine": "bippy-a5840b7849dd"
         }
      }
   },
   "cveMetadata": {
      "assignerOrgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038",
      "cveID": "CVE-2024-35932",
      "requesterUserId": "gregkh@kernel.org",
      "serial": "1",
      "state": "PUBLISHED"
   },
   "dataType": "CVE_RECORD",
   "dataVersion": "5.0"
}
