[Intel-gfx] [bug report] drm/i915/guc: Use GuC submission API version number

[Dan Carpenter <error27@gmail.com>]

Hello John Harrison,

The patch 9bbba0667f37: "drm/i915/guc: Use GuC submission API version
number" from Nov 29, 2022, leads to the following Smatch static
checker warning:

	drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c:821 intel_uc_fw_fetch()
	warn: passing zero to 'ERR_PTR'

drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c
    709 int intel_uc_fw_fetch(struct intel_uc_fw *uc_fw)
    710 {
    711         struct intel_gt *gt = __uc_fw_to_gt(uc_fw);
    712         struct drm_i915_private *i915 = gt->i915;
    713         struct intel_uc_fw_file file_ideal;
    714         struct drm_i915_gem_object *obj;
    715         const struct firmware *fw = NULL;
    716         bool old_ver = false;
    717         int err;
    718 
    719         GEM_BUG_ON(!gt->wopcm.size);
    720         GEM_BUG_ON(!intel_uc_fw_is_enabled(uc_fw));
    721 
    722         err = i915_inject_probe_error(i915, -ENXIO);
    723         if (err)
    724                 goto fail;
    725 
    726         __force_fw_fetch_failures(uc_fw, -EINVAL);
    727         __force_fw_fetch_failures(uc_fw, -ESTALE);
    728 
    729         err = try_firmware_load(uc_fw, &fw);
    730         memcpy(&file_ideal, &uc_fw->file_wanted, sizeof(file_ideal));
    731 
    732         /* Any error is terminal if overriding. Don't bother searching for older versions */
    733         if (err && intel_uc_fw_is_overridden(uc_fw))
    734                 goto fail;
    735 
    736         while (err == -ENOENT) {
    737                 old_ver = true;
    738 
    739                 __uc_fw_auto_select(i915, uc_fw);
    740                 if (!uc_fw->file_selected.path) {
    741                         /*
    742                          * No more options! But set the path back to something
    743                          * valid just in case it gets dereferenced.
    744                          */
    745                         uc_fw->file_selected.path = file_ideal.path;
    746 
    747                         /* Also, preserve the version that was really wanted */
    748                         memcpy(&uc_fw->file_wanted, &file_ideal, sizeof(uc_fw->file_wanted));
    749                         break;
    750                 }
    751 
    752                 err = try_firmware_load(uc_fw, &fw);
    753         }
    754 
    755         if (err)
    756                 goto fail;
    757 
    758         err = check_fw_header(gt, fw, uc_fw);
    759         if (err)
    760                 goto fail;
    761 
    762         if (uc_fw->type == INTEL_UC_FW_TYPE_GUC && !guc_check_version_range(uc_fw))
    763                 goto fail;
                        ^^^^^^^^^
Should "err" be set on this path?


    764 
    765         if (uc_fw->file_wanted.ver.major && uc_fw->file_selected.ver.major) {
    766                 /* Check the file's major version was as it claimed */
    767                 if (uc_fw->file_selected.ver.major != uc_fw->file_wanted.ver.major) {
    768                         gt_notice(gt, "%s firmware %s: unexpected version: %u.%u != %u.%u\n",
    769                                   intel_uc_fw_type_repr(uc_fw->type), uc_fw->file_selected.path,
    770                                   uc_fw->file_selected.ver.major, uc_fw->file_selected.ver.minor,
    771                                   uc_fw->file_wanted.ver.major, uc_fw->file_wanted.ver.minor);
    772                         if (!intel_uc_fw_is_overridden(uc_fw)) {
    773                                 err = -ENOEXEC;
    774                                 goto fail;
    775                         }
    776                 } else {
    777                         if (uc_fw->file_selected.ver.minor < uc_fw->file_wanted.ver.minor)
    778                                 old_ver = true;
    779                 }
    780         }
    781 
    782         if (old_ver && uc_fw->file_selected.ver.major) {
    783                 /* Preserve the version that was really wanted */
    784                 memcpy(&uc_fw->file_wanted, &file_ideal, sizeof(uc_fw->file_wanted));
    785 
    786                 gt_notice(gt, "%s firmware %s (%d.%d) is recommended, but only %s (%d.%d) was found\n",
    787                           intel_uc_fw_type_repr(uc_fw->type),
    788                           uc_fw->file_wanted.path,
    789                           uc_fw->file_wanted.ver.major, uc_fw->file_wanted.ver.minor,
    790                           uc_fw->file_selected.path,
    791                           uc_fw->file_selected.ver.major, uc_fw->file_selected.ver.minor);
    792                 gt_info(gt, "Consider updating your linux-firmware pkg or downloading from %s\n",
    793                         INTEL_UC_FIRMWARE_URL);
    794         }
    795 
    796         if (HAS_LMEM(i915)) {
    797                 obj = i915_gem_object_create_lmem_from_data(i915, fw->data, fw->size);
    798                 if (!IS_ERR(obj))
    799                         obj->flags |= I915_BO_ALLOC_PM_EARLY;
    800         } else {
    801                 obj = i915_gem_object_create_shmem_from_data(i915, fw->data, fw->size);
    802         }
    803 
    804         if (IS_ERR(obj)) {
    805                 err = PTR_ERR(obj);
    806                 goto fail;
    807         }
    808 
    809         uc_fw->obj = obj;
    810         uc_fw->size = fw->size;
    811         intel_uc_fw_change_status(uc_fw, INTEL_UC_FIRMWARE_AVAILABLE);
    812 
    813         release_firmware(fw);
    814         return 0;
    815 
    816 fail:
    817         intel_uc_fw_change_status(uc_fw, err == -ENOENT ?
    818                                   INTEL_UC_FIRMWARE_MISSING :
    819                                   INTEL_UC_FIRMWARE_ERROR);
    820 
--> 821         gt_probe_error(gt, "%s firmware %s: fetch failed %pe\n",
    822                        intel_uc_fw_type_repr(uc_fw->type), uc_fw->file_selected.path, ERR_PTR(err));
    823         gt_info(gt, "%s firmware(s) can be downloaded from %s\n",
    824                 intel_uc_fw_type_repr(uc_fw->type), INTEL_UC_FIRMWARE_URL);
    825 
    826         release_firmware(fw);                /* OK even if fw is NULL */
    827         return err;
    828 }

regards,
dan carpenter