| Message ID | 20230719145317.1485514-1-andrzej.hajda@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Revert "Revert "drm/i915: Hold reference to intel_context over life of i915_request"" | expand |
On 19.07.2023 20:58, Patchwork wrote: > Project List - Patchwork *Patch Details* > *Series:* Revert "Revert "drm/i915: Hold reference to intel_context > over life of i915_request"" > *URL:* https://patchwork.freedesktop.org/series/120990/ > *State:* failure > *Details:* > https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/index.html > > > CI Bug Log - changes from CI_DRM_13396 -> Patchwork_120990v1 > > > Summary > > *FAILURE* > > Serious unknown changes coming with Patchwork_120990v1 absolutely need > to be > verified manually. > > If you think the reported changes have nothing to do with the changes > introduced in Patchwork_120990v1, please notify your bug team to allow > them > to document this new failure mode, which will reduce false positives > in CI. > > External URL: > https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/index.html > > > Participating hosts (42 -> 43) > > Additional (2): fi-kbl-soraka bat-rpls-2 > Missing (1): fi-snb-2520m > > > Possible new issues > > Here are the unknown changes that may have been introduced in > Patchwork_120990v1: > > > IGT changes > > > Possible regressions > > * > > igt@debugfs_test@read_all_entries: > > o bat-mtlp-6: PASS > <https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_13396/bat-mtlp-6/igt@debugfs_test@read_all_entries.html> > -> DMESG-WARN > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/bat-mtlp-6/igt@debugfs_test@read_all_entries.html> > Known bug: https://gitlab.freedesktop.org/drm/intel/-/issues/8940 > * > * > > igt@i915_selftest@live@gt_mocs: > > o bat-adlp-9: PASS > <https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_13396/bat-adlp-9/igt@i915_selftest@live@gt_mocs.html> > -> DMESG-WARN > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/bat-adlp-9/igt@i915_selftest@live@gt_mocs.html> > Occasional bug: https://gitlab.freedesktop.org/drm/intel/-/issues/5830 Does not seems to be related. Regards Andrzej > * > > > Warnings > > * igt@i915_selftest@live@slpc: > o bat-mtlp-6: DMESG-WARN > <https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_13396/bat-mtlp-6/igt@i915_selftest@live@slpc.html> > (i915#6367 > <https://gitlab.freedesktop.org/drm/intel/issues/6367>) -> > DMESG-WARN > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/bat-mtlp-6/igt@i915_selftest@live@slpc.html> > > > Known issues > > Here are the changes found in Patchwork_120990v1 that come from known > issues: > > > IGT changes > > > Issues hit > > * > > igt@debugfs_test@basic-hwmon: > > o bat-rpls-2: NOTRUN -> SKIP > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/bat-rpls-2/igt@debugfs_test@basic-hwmon.html> > (i915#7456 <https://gitlab.freedesktop.org/drm/intel/issues/7456>) > * > > igt@fbdev@info: > > o bat-rpls-2: NOTRUN -> SKIP > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/bat-rpls-2/igt@fbdev@info.html> > (i915#1849 > <https://gitlab.freedesktop.org/drm/intel/issues/1849> / > i915#2582 <https://gitlab.freedesktop.org/drm/intel/issues/2582>) > * > > igt@fbdev@read: > > o bat-rpls-2: NOTRUN -> SKIP > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/bat-rpls-2/igt@fbdev@read.html> > (i915#2582 > <https://gitlab.freedesktop.org/drm/intel/issues/2582>) +3 > similar issues > * > > igt@gem_huc_copy@huc-copy: > > o fi-kbl-soraka: NOTRUN -> SKIP > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/fi-kbl-soraka/igt@gem_huc_copy@huc-copy.html> > (fdo#109271 > <https://bugs.freedesktop.org/show_bug.cgi?id=109271> / > i915#2190 <https://gitlab.freedesktop.org/drm/intel/issues/2190>) > * > > igt@gem_lmem_swapping@basic: > > o fi-kbl-soraka: NOTRUN -> SKIP > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/fi-kbl-soraka/igt@gem_lmem_swapping@basic.html> > (fdo#109271 > <https://bugs.freedesktop.org/show_bug.cgi?id=109271> / > i915#4613 > <https://gitlab.freedesktop.org/drm/intel/issues/4613>) +3 > similar issues > * > > igt@gem_lmem_swapping@verify-random: > > o bat-rpls-2: NOTRUN -> SKIP > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/bat-rpls-2/igt@gem_lmem_swapping@verify-random.html> > (i915#4613 > <https://gitlab.freedesktop.org/drm/intel/issues/4613>) +3 > similar issues > * > > igt@gem_tiled_pread_basic: > > o bat-rpls-2: NOTRUN -> SKIP > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/bat-rpls-2/igt@gem_tiled_pread_basic.html> > (i915#3282 <https://gitlab.freedesktop.org/drm/intel/issues/3282>) > * > > igt@i915_pm_backlight@basic-brightness: > > o bat-rpls-2: NOTRUN -> SKIP > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/bat-rpls-2/igt@i915_pm_backlight@basic-brightness.html> > (i915#7561 <https://gitlab.freedesktop.org/drm/intel/issues/7561>) > * > > igt@i915_pm_rpm@basic-rte: > > o fi-cfl-8109u: PASS > <https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_13396/fi-cfl-8109u/igt@i915_pm_rpm@basic-rte.html> > -> FAIL > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/fi-cfl-8109u/igt@i915_pm_rpm@basic-rte.html> > (i915#7940 <https://gitlab.freedesktop.org/drm/intel/issues/7940>) > * > > igt@i915_pm_rps@basic-api: > > o bat-rpls-2: NOTRUN -> SKIP > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/bat-rpls-2/igt@i915_pm_rps@basic-api.html> > (i915#6621 <https://gitlab.freedesktop.org/drm/intel/issues/6621>) > * > > igt@i915_selftest@live@gt_pm: > > o > > bat-rpls-2: NOTRUN -> DMESG-FAIL > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/bat-rpls-2/igt@i915_selftest@live@gt_pm.html> > (i915#4258 > <https://gitlab.freedesktop.org/drm/intel/issues/4258> / > i915#7913 <https://gitlab.freedesktop.org/drm/intel/issues/7913>) > > o > > fi-kbl-soraka: NOTRUN -> DMESG-FAIL > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/fi-kbl-soraka/igt@i915_selftest@live@gt_pm.html> > (i915#1886 > <https://gitlab.freedesktop.org/drm/intel/issues/1886> / > i915#7913 <https://gitlab.freedesktop.org/drm/intel/issues/7913>) > > * > > igt@i915_selftest@live@migrate: > > o > > bat-rpls-2: NOTRUN -> DMESG-FAIL > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/bat-rpls-2/igt@i915_selftest@live@migrate.html> > (i915#7699 > <https://gitlab.freedesktop.org/drm/intel/issues/7699> / > i915#7913 <https://gitlab.freedesktop.org/drm/intel/issues/7913>) > > o > > bat-dg2-11: PASS > <https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_13396/bat-dg2-11/igt@i915_selftest@live@migrate.html> > -> DMESG-WARN > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/bat-dg2-11/igt@i915_selftest@live@migrate.html> > (i915#7699 <https://gitlab.freedesktop.org/drm/intel/issues/7699>) > > * > > igt@i915_selftest@live@mman: > > o bat-rpls-2: NOTRUN -> TIMEOUT > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/bat-rpls-2/igt@i915_selftest@live@mman.html> > (i915#6794 > <https://gitlab.freedesktop.org/drm/intel/issues/6794> / > i915#7392 <https://gitlab.freedesktop.org/drm/intel/issues/7392>) > * > > igt@i915_selftest@live@requests: > > o bat-mtlp-8: PASS > <https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_13396/bat-mtlp-8/igt@i915_selftest@live@requests.html> > -> DMESG-FAIL > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/bat-mtlp-8/igt@i915_selftest@live@requests.html> > (i915#8497 <https://gitlab.freedesktop.org/drm/intel/issues/8497>) > * > > igt@i915_selftest@live@slpc: > > o bat-mtlp-8: PASS > <https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_13396/bat-mtlp-8/igt@i915_selftest@live@slpc.html> > -> DMESG-WARN > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/bat-mtlp-8/igt@i915_selftest@live@slpc.html> > (i915#6367 <https://gitlab.freedesktop.org/drm/intel/issues/6367>) > * > > igt@i915_suspend@basic-s2idle-without-i915: > > o bat-rpls-2: NOTRUN -> WARN > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/bat-rpls-2/igt@i915_suspend@basic-s2idle-without-i915.html> > (i915#8747 <https://gitlab.freedesktop.org/drm/intel/issues/8747>) > * > > igt@kms_busy@basic: > > o bat-rpls-2: NOTRUN -> SKIP > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/bat-rpls-2/igt@kms_busy@basic.html> > (i915#1845 > <https://gitlab.freedesktop.org/drm/intel/issues/1845>) +15 > similar issues > * > > igt@kms_chamelium_edid@hdmi-edid-read: > > o bat-rpls-2: NOTRUN -> SKIP > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/bat-rpls-2/igt@kms_chamelium_edid@hdmi-edid-read.html> > (i915#7828 > <https://gitlab.freedesktop.org/drm/intel/issues/7828>) +8 > similar issues > * > > igt@kms_cursor_legacy@basic-busy-flip-before-cursor-atomic: > > o fi-kbl-soraka: NOTRUN -> SKIP > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/fi-kbl-soraka/igt@kms_cursor_legacy@basic-busy-flip-before-cursor-atomic.html> > (fdo#109271 > <https://bugs.freedesktop.org/show_bug.cgi?id=109271>) +15 > similar issues > * > > igt@kms_flip@basic-flip-vs-dpms: > > o bat-rpls-2: NOTRUN -> SKIP > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/bat-rpls-2/igt@kms_flip@basic-flip-vs-dpms.html> > (i915#3637 > <https://gitlab.freedesktop.org/drm/intel/issues/3637>) +3 > similar issues > * > > igt@kms_force_connector_basic@force-load-detect: > > o bat-rpls-2: NOTRUN -> SKIP > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/bat-rpls-2/igt@kms_force_connector_basic@force-load-detect.html> > (fdo#109285 <https://bugs.freedesktop.org/show_bug.cgi?id=109285>) > * > > igt@kms_frontbuffer_tracking@basic: > > o bat-rpls-2: NOTRUN -> SKIP > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/bat-rpls-2/igt@kms_frontbuffer_tracking@basic.html> > (i915#1849 <https://gitlab.freedesktop.org/drm/intel/issues/1849>) > * > > igt@kms_psr@primary_mmap_gtt: > > o bat-rplp-1: NOTRUN -> SKIP > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/bat-rplp-1/igt@kms_psr@primary_mmap_gtt.html> > (i915#1072 <https://gitlab.freedesktop.org/drm/intel/issues/1072>) > * > > igt@kms_psr@sprite_plane_onoff: > > o bat-rpls-2: NOTRUN -> SKIP > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/bat-rpls-2/igt@kms_psr@sprite_plane_onoff.html> > (i915#1072 > <https://gitlab.freedesktop.org/drm/intel/issues/1072>) +3 > similar issues > * > > igt@kms_setmode@basic-clone-single-crtc: > > o > > bat-rplp-1: NOTRUN -> ABORT > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/bat-rplp-1/igt@kms_setmode@basic-clone-single-crtc.html> > (i915#8260 > <https://gitlab.freedesktop.org/drm/intel/issues/8260> / > i915#8668 <https://gitlab.freedesktop.org/drm/intel/issues/8668>) > > o > > bat-rpls-2: NOTRUN -> SKIP > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/bat-rpls-2/igt@kms_setmode@basic-clone-single-crtc.html> > (i915#3555 <https://gitlab.freedesktop.org/drm/intel/issues/3555>) > > * > > igt@prime_vgem@basic-fence-flip: > > o bat-rpls-2: NOTRUN -> SKIP > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/bat-rpls-2/igt@prime_vgem@basic-fence-flip.html> > (fdo#109295 > <https://bugs.freedesktop.org/show_bug.cgi?id=109295> / > i915#1845 > <https://gitlab.freedesktop.org/drm/intel/issues/1845> / > i915#3708 <https://gitlab.freedesktop.org/drm/intel/issues/3708>) > * > > igt@prime_vgem@basic-write: > > o bat-rpls-2: NOTRUN -> SKIP > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/bat-rpls-2/igt@prime_vgem@basic-write.html> > (fdo#109295 > <https://bugs.freedesktop.org/show_bug.cgi?id=109295> / > i915#3708 > <https://gitlab.freedesktop.org/drm/intel/issues/3708>) +2 > similar issues > > > Possible fixes > > * > > igt@core_auth@basic-auth: > > o bat-mtlp-6: DMESG-WARN > <https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_13396/bat-mtlp-6/igt@core_auth@basic-auth.html> > -> PASS > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/bat-mtlp-6/igt@core_auth@basic-auth.html> > * > > igt@i915_pm_rpm@basic-rte: > > o fi-tgl-1115g4: FAIL > <https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_13396/fi-tgl-1115g4/igt@i915_pm_rpm@basic-rte.html> > (i915#7940 > <https://gitlab.freedesktop.org/drm/intel/issues/7940>) -> > PASS > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/fi-tgl-1115g4/igt@i915_pm_rpm@basic-rte.html> > * > > igt@i915_selftest@live@gt_heartbeat: > > o fi-glk-j4005: DMESG-FAIL > <https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_13396/fi-glk-j4005/igt@i915_selftest@live@gt_heartbeat.html> > (i915#5334 > <https://gitlab.freedesktop.org/drm/intel/issues/5334>) -> > PASS > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/fi-glk-j4005/igt@i915_selftest@live@gt_heartbeat.html> > * > > igt@i915_selftest@live@guc: > > o bat-rpls-1: DMESG-WARN > <https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_13396/bat-rpls-1/igt@i915_selftest@live@guc.html> > (i915#7852 > <https://gitlab.freedesktop.org/drm/intel/issues/7852>) -> > PASS > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/bat-rpls-1/igt@i915_selftest@live@guc.html> > > > Warnings > > * > > igt@i915_module_load@load: > > o bat-adlp-11: DMESG-WARN > <https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_13396/bat-adlp-11/igt@i915_module_load@load.html> > (i915#4423 > <https://gitlab.freedesktop.org/drm/intel/issues/4423>) -> > ABORT > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/bat-adlp-11/igt@i915_module_load@load.html> > (i915#4423 <https://gitlab.freedesktop.org/drm/intel/issues/4423>) > * > > igt@i915_pm_rpm@basic-pci-d3-state: > > o fi-cfl-guc: FAIL > <https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_13396/fi-cfl-guc/igt@i915_pm_rpm@basic-pci-d3-state.html> > (i915#7691 > <https://gitlab.freedesktop.org/drm/intel/issues/7691>) -> > FAIL > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/fi-cfl-guc/igt@i915_pm_rpm@basic-pci-d3-state.html> > (i915#7940 <https://gitlab.freedesktop.org/drm/intel/issues/7940>) > * > > igt@kms_psr@sprite_plane_onoff: > > o bat-rplp-1: ABORT > <https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_13396/bat-rplp-1/igt@kms_psr@sprite_plane_onoff.html> > (i915#8442 > <https://gitlab.freedesktop.org/drm/intel/issues/8442> / > i915#8668 > <https://gitlab.freedesktop.org/drm/intel/issues/8668> / > i915#8712 > <https://gitlab.freedesktop.org/drm/intel/issues/8712>) -> > SKIP > <https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_120990v1/bat-rplp-1/igt@kms_psr@sprite_plane_onoff.html> > (i915#1072 <https://gitlab.freedesktop.org/drm/intel/issues/1072>) > > {name}: This element is suppressed. This means it is ignored when > computing > the status of the difference (SUCCESS, WARNING, or FAILURE). > > > Build changes > > * Linux: CI_DRM_13396 -> Patchwork_120990v1 > > CI-20190529: 20190529 > CI_DRM_13396: da1bb773ff84001b185e7bec54b32b89dff44f91 @ > git://anongit.freedesktop.org/gfx-ci/linux > IGT_7394: 3b0c82d7e9f1b8708d351243de7f227153793ede @ > https://gitlab.freedesktop.org/drm/igt-gpu-tools.git > Patchwork_120990v1: da1bb773ff84001b185e7bec54b32b89dff44f91 @ > git://anongit.freedesktop.org/gfx-ci/linux > > > Linux commits > > cf364789fcd3 Revert "Revert "drm/i915: Hold reference to intel_context > over life of i915_request"" >
diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c index 894068bb37b6f1..c5fe199b046d01 100644 --- a/drivers/gpu/drm/i915/i915_request.c +++ b/drivers/gpu/drm/i915/i915_request.c @@ -134,42 +134,17 @@ static void i915_fence_release(struct dma_fence *fence) i915_sw_fence_fini(&rq->semaphore); /* - * Keep one request on each engine for reserved use under mempressure + * Keep one request on each engine for reserved use under mempressure, * do not use with virtual engines as this really is only needed for * kernel contexts. - * - * We do not hold a reference to the engine here and so have to be - * very careful in what rq->engine we poke. The virtual engine is - * referenced via the rq->context and we released that ref during - * i915_request_retire(), ergo we must not dereference a virtual - * engine here. Not that we would want to, as the only consumer of - * the reserved engine->request_pool is the power management parking, - * which must-not-fail, and that is only run on the physical engines. - * - * Since the request must have been executed to be have completed, - * we know that it will have been processed by the HW and will - * not be unsubmitted again, so rq->engine and rq->execution_mask - * at this point is stable. rq->execution_mask will be a single - * bit if the last and _only_ engine it could execution on was a - * physical engine, if it's multiple bits then it started on and - * could still be on a virtual engine. Thus if the mask is not a - * power-of-two we assume that rq->engine may still be a virtual - * engine and so a dangling invalid pointer that we cannot dereference - * - * For example, consider the flow of a bonded request through a virtual - * engine. The request is created with a wide engine mask (all engines - * that we might execute on). On processing the bond, the request mask - * is reduced to one or more engines. If the request is subsequently - * bound to a single engine, it will then be constrained to only - * execute on that engine and never returned to the virtual engine - * after timeslicing away, see __unwind_incomplete_requests(). Thus we - * know that if the rq->execution_mask is a single bit, rq->engine - * can be a physical engine with the exact corresponding mask. */ if (!intel_engine_is_virtual(rq->engine) && - is_power_of_2(rq->execution_mask) && - !cmpxchg(&rq->engine->request_pool, NULL, rq)) + !cmpxchg(&rq->engine->request_pool, NULL, rq)) { + intel_context_put(rq->context); return; + } + + intel_context_put(rq->context); kmem_cache_free(slab_requests, rq); } @@ -946,7 +921,19 @@ __i915_request_create(struct intel_context *ce, gfp_t gfp) } } - rq->context = ce; + /* + * Hold a reference to the intel_context over life of an i915_request. + * Without this an i915_request can exist after the context has been + * destroyed (e.g. request retired, context closed, but user space holds + * a reference to the request from an out fence). In the case of GuC + * submission + virtual engine, the engine that the request references + * is also destroyed which can trigger bad pointer dref in fence ops + * (e.g. i915_fence_get_driver_name). We could likely change these + * functions to avoid touching the engine but let's just be safe and + * hold the intel_context reference. In execlist mode the request always + * eventually points to a physical engine so this isn't an issue. + */ + rq->context = intel_context_get(ce); rq->engine = ce->engine; rq->ring = ce->ring; rq->execution_mask = ce->engine->mask; @@ -1022,6 +1009,7 @@ __i915_request_create(struct intel_context *ce, gfp_t gfp) GEM_BUG_ON(!list_empty(&rq->sched.waiters_list)); err_free: + intel_context_put(ce); kmem_cache_free(slab_requests, rq); err_unreserve: intel_context_unpin(ce);
This reverts commit bcb9aa45d5a0e11ef91245330c53cde214d15e8d. The problem with this patch is that it makes rq->engine dangling pointer after context removal. At least two places were located where it ends with errors: - i915_fence_release: intel_engine_is_virtual(rq->engine), - i915_request_wait_timeout: mutex_(acquire|release)(&rq->engine->gt...) It is possible there are more such places. Taking context reference prevents this behaviour. Commit message suggested the patch prevented reference loop in VM_BIND, but since VM_BIND was dropped the revert hopefuly should be safe. The patch fixes bug detected by KASAN with following signature: i915 0000:00:02.0: [drm:i915_drop_caches_set [i915]] Dropping caches: 0x0000005c [0x0000005c] BUG: KASAN: slab-use-after-free in i915_fence_release+0x2a2/0x2f0 [i915] Read of size 4 at addr ffff88813ffda6e8 by task kworker/u32:10/157 ... Allocated by task 1184: ... guc_create_virtual+0x4d/0x1160 [i915] i915_gem_create_context+0x11ee/0x18c0 [i915] ... Freed by task 151: ... intel_guc_deregister_done_process_msg+0x324/0x6d0 [i915] ... Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/7926 Signed-off-by: Andrzej Hajda <andrzej.hajda@intel.com> --- Hi Niranjana, Matt, Could you look at this revert, to verify if situation described in reverted patch will not happen now, without VM_BIND. Regards Andrzej --- drivers/gpu/drm/i915/i915_request.c | 52 +++++++++++------------------ 1 file changed, 20 insertions(+), 32 deletions(-)