The patch below does not apply to the 6.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.10.y git checkout FETCH_HEAD git cherry-pick -x 2d2be279f1ca9e7288282d4214f16eea8a727cdb # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2024100727-lego-panther-fea9@gregkh' --subject-prefix 'PATCH 6.10.y' HEAD^..

Possible dependencies:

2d2be279f1ca ("drm/xe: fix UAF around queue destruction") 3f371a98dead ("drm/xe: Delete unused GuC submission_state.suspend")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 2d2be279f1ca9e7288282d4214f16eea8a727cdb Mon Sep 17 00:00:00 2001 From: Matthew Auld matthew.auld@intel.com Date: Mon, 23 Sep 2024 15:56:48 +0100 Subject: [PATCH] drm/xe: fix UAF around queue destruction

We currently do stuff like queuing the final destruction step on a random system wq, which will outlive the driver instance. With bad timing we can teardown the driver with one or more work workqueue still being alive leading to various UAF splats. Add a fini step to ensure user queues are properly torn down. At this point GuC should already be nuked so queue itself should no longer be referenced from hw pov.

v2 (Matt B) - Looks much safer to use a waitqueue and then just wait for the xa_array to become empty before triggering the drain.

Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/2317 Fixes: dd08ebf6c352 ("drm/xe: Introduce a new DRM driver for Intel GPUs") Signed-off-by: Matthew Auld matthew.auld@intel.com Cc: Matthew Brost matthew.brost@intel.com Cc: stable@vger.kernel.org # v6.8+ Reviewed-by: Matthew Brost matthew.brost@intel.com Link: https://patchwork.freedesktop.org/patch/msgid/20240923145647.77707-2-matthew... (cherry picked from commit 861108666cc0e999cffeab6aff17b662e68774e3) Signed-off-by: Lucas De Marchi lucas.demarchi@intel.com

diff --git a/drivers/gpu/drm/xe/xe_device.c b/drivers/gpu/drm/xe/xe_device.c index 70d4e4d46c3c..74e593caf87c 100644 --- a/drivers/gpu/drm/xe/xe_device.c +++ b/drivers/gpu/drm/xe/xe_device.c @@ -298,6 +298,9 @@ static void xe_device_destroy(struct drm_device *dev, void *dummy) if (xe->unordered_wq) destroy_workqueue(xe->unordered_wq);

+ if (xe->destroy_wq) + destroy_workqueue(xe->destroy_wq); + ttm_device_fini(&xe->ttm); }

@@ -363,8 +366,9 @@ struct xe_device *xe_device_create(struct pci_dev *pdev, xe->preempt_fence_wq = alloc_ordered_workqueue("xe-preempt-fence-wq", 0); xe->ordered_wq = alloc_ordered_workqueue("xe-ordered-wq", 0); xe->unordered_wq = alloc_workqueue("xe-unordered-wq", 0, 0); + xe->destroy_wq = alloc_workqueue("xe-destroy-wq", 0, 0); if (!xe->ordered_wq || !xe->unordered_wq || - !xe->preempt_fence_wq) { + !xe->preempt_fence_wq || !xe->destroy_wq) { /* * Cleanup done in xe_device_destroy via * drmm_add_action_or_reset register above diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h index ec7eb7811126..24c8c2d20676 100644 --- a/drivers/gpu/drm/xe/xe_device_types.h +++ b/drivers/gpu/drm/xe/xe_device_types.h @@ -396,6 +396,9 @@ struct xe_device { /** @unordered_wq: used to serialize unordered work, mostly display */ struct workqueue_struct *unordered_wq;

+ /** @destroy_wq: used to serialize user destroy work, like queue */ + struct workqueue_struct *destroy_wq; + /** @tiles: device tiles */ struct xe_tile tiles[XE_MAX_TILES_PER_DEVICE];

diff --git a/drivers/gpu/drm/xe/xe_guc_submit.c b/drivers/gpu/drm/xe/xe_guc_submit.c index 715c761dc7d6..98a6a385a796 100644 --- a/drivers/gpu/drm/xe/xe_guc_submit.c +++ b/drivers/gpu/drm/xe/xe_guc_submit.c @@ -276,10 +276,26 @@ static struct workqueue_struct *get_submit_wq(struct xe_guc *guc) } #endif

+static void xe_guc_submit_fini(struct xe_guc *guc) +{ + struct xe_device *xe = guc_to_xe(guc); + struct xe_gt *gt = guc_to_gt(guc); + int ret; + + ret = wait_event_timeout(guc->submission_state.fini_wq, + xa_empty(&guc->submission_state.exec_queue_lookup), + HZ * 5); + + drain_workqueue(xe->destroy_wq); + + xe_gt_assert(gt, ret); +} + static void guc_submit_fini(struct drm_device *drm, void *arg) { struct xe_guc *guc = arg;

+ xe_guc_submit_fini(guc); xa_destroy(&guc->submission_state.exec_queue_lookup); free_submit_wq(guc); } @@ -351,6 +367,8 @@ int xe_guc_submit_init(struct xe_guc *guc, unsigned int num_ids)

xa_init(&guc->submission_state.exec_queue_lookup);

+ init_waitqueue_head(&guc->submission_state.fini_wq); + primelockdep(guc);

return drmm_add_action_or_reset(&xe->drm, guc_submit_fini, guc); @@ -367,6 +385,9 @@ static void __release_guc_id(struct xe_guc *guc, struct xe_exec_queue *q, u32 xa

xe_guc_id_mgr_release_locked(&guc->submission_state.idm, q->guc->id, q->width); + + if (xa_empty(&guc->submission_state.exec_queue_lookup)) + wake_up(&guc->submission_state.fini_wq); }

static int alloc_guc_id(struct xe_guc *guc, struct xe_exec_queue *q) @@ -1274,13 +1295,16 @@ static void __guc_exec_queue_fini_async(struct work_struct *w)

static void guc_exec_queue_fini_async(struct xe_exec_queue *q) { + struct xe_guc *guc = exec_queue_to_guc(q); + struct xe_device *xe = guc_to_xe(guc); + INIT_WORK(&q->guc->fini_async, __guc_exec_queue_fini_async);

/* We must block on kernel engines so slabs are empty on driver unload */ if (q->flags & EXEC_QUEUE_FLAG_PERMANENT || exec_queue_wedged(q)) __guc_exec_queue_fini_async(&q->guc->fini_async); else - queue_work(system_wq, &q->guc->fini_async); + queue_work(xe->destroy_wq, &q->guc->fini_async); }

static void __guc_exec_queue_fini(struct xe_guc *guc, struct xe_exec_queue *q) diff --git a/drivers/gpu/drm/xe/xe_guc_types.h b/drivers/gpu/drm/xe/xe_guc_types.h index 546ac6350a31..69046f698271 100644 --- a/drivers/gpu/drm/xe/xe_guc_types.h +++ b/drivers/gpu/drm/xe/xe_guc_types.h @@ -81,6 +81,8 @@ struct xe_guc { #endif /** @submission_state.enabled: submission is enabled */ bool enabled; + /** @submission_state.fini_wq: submit fini wait queue */ + wait_queue_head_t fini_wq; } submission_state; /** @hwconfig: Hardware config state */ struct {