Hello,
Henrik notified me that UDF in 5.15 kernel is failing for him, likely
because commit 1ea1cd11c72d ("udf: Fix directory iteration for longer tail
extents") is missing 5.15 stable tree. Basically wherever d16076d9b684b got
backported, 1ea1cd11c72d needs to be backported as well (I'm sorry for
forgetting to add proper Fixes tag back then).
Honza
--
Jan Kara <jack(a)suse.com>
SUSE Labs, CR
When the xe pm_notifier evicts for suspend / hibernate, there might be
racing tasks trying to re-validate again. This can lead to suspend taking
excessive time or get stuck in a live-lock. This behaviour becomes
much worse with the fix that actually makes re-validation bring back
bos to VRAM rather than letting them remain in TT.
Prevent that by having exec and the rebind worker waiting for a completion
that is set to block by the pm_notifier before suspend and is signaled
by the pm_notifier after resume / wakeup.
It's probably still possible to craft malicious applications that block
suspending. More work is pending to fix that.
Link: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/4288
Fixes: c6a4d46ec1d7 ("drm/xe: evict user memory in PM notifier")
Cc: Matthew Auld <matthew.auld(a)intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi(a)intel.com>
Cc: <stable(a)vger.kernel.org> # v6.16+
Signed-off-by: Thomas Hellström <thomas.hellstrom(a)linux.intel.com>
---
drivers/gpu/drm/xe/xe_device_types.h | 2 ++
drivers/gpu/drm/xe/xe_exec.c | 9 +++++++++
drivers/gpu/drm/xe/xe_pm.c | 4 ++++
drivers/gpu/drm/xe/xe_vm.c | 14 ++++++++++++++
4 files changed, 29 insertions(+)
diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h
index 092004d14db2..6602bd678cbc 100644
--- a/drivers/gpu/drm/xe/xe_device_types.h
+++ b/drivers/gpu/drm/xe/xe_device_types.h
@@ -507,6 +507,8 @@ struct xe_device {
/** @pm_notifier: Our PM notifier to perform actions in response to various PM events. */
struct notifier_block pm_notifier;
+ /** @pm_block: Completion to block validating tasks on suspend / hibernate prepare */
+ struct completion pm_block;
/** @pmt: Support the PMT driver callback interface */
struct {
diff --git a/drivers/gpu/drm/xe/xe_exec.c b/drivers/gpu/drm/xe/xe_exec.c
index 44364c042ad7..374c831e691b 100644
--- a/drivers/gpu/drm/xe/xe_exec.c
+++ b/drivers/gpu/drm/xe/xe_exec.c
@@ -237,6 +237,15 @@ int xe_exec_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
goto err_unlock_list;
}
+ /*
+ * It's OK to block interruptible here with the vm lock held, since
+ * on task freezing during suspend / hibernate, the call will
+ * return -ERESTARTSYS and the IOCTL will be rerun.
+ */
+ err = wait_for_completion_interruptible(&xe->pm_block);
+ if (err)
+ goto err_unlock_list;
+
vm_exec.vm = &vm->gpuvm;
vm_exec.flags = DRM_EXEC_INTERRUPTIBLE_WAIT;
if (xe_vm_in_lr_mode(vm)) {
diff --git a/drivers/gpu/drm/xe/xe_pm.c b/drivers/gpu/drm/xe/xe_pm.c
index bee9aacd82e7..f4c7a84270ea 100644
--- a/drivers/gpu/drm/xe/xe_pm.c
+++ b/drivers/gpu/drm/xe/xe_pm.c
@@ -306,6 +306,7 @@ static int xe_pm_notifier_callback(struct notifier_block *nb,
switch (action) {
case PM_HIBERNATION_PREPARE:
case PM_SUSPEND_PREPARE:
+ reinit_completion(&xe->pm_block);
xe_pm_runtime_get(xe);
err = xe_bo_evict_all_user(xe);
if (err)
@@ -322,6 +323,7 @@ static int xe_pm_notifier_callback(struct notifier_block *nb,
break;
case PM_POST_HIBERNATION:
case PM_POST_SUSPEND:
+ complete_all(&xe->pm_block);
xe_bo_notifier_unprepare_all_pinned(xe);
xe_pm_runtime_put(xe);
break;
@@ -348,6 +350,8 @@ int xe_pm_init(struct xe_device *xe)
if (err)
return err;
+ init_completion(&xe->pm_block);
+ complete_all(&xe->pm_block);
/* For now suspend/resume is only allowed with GuC */
if (!xe_device_uc_enabled(xe))
return 0;
diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
index 3ff3c67aa79d..edcdb0528f2a 100644
--- a/drivers/gpu/drm/xe/xe_vm.c
+++ b/drivers/gpu/drm/xe/xe_vm.c
@@ -394,6 +394,9 @@ static int xe_gpuvm_validate(struct drm_gpuvm_bo *vm_bo, struct drm_exec *exec)
list_move_tail(&gpuva_to_vma(gpuva)->combined_links.rebind,
&vm->rebind_list);
+ if (!try_wait_for_completion(&vm->xe->pm_block))
+ return -EAGAIN;
+
ret = xe_bo_validate(gem_to_xe_bo(vm_bo->obj), vm, false);
if (ret)
return ret;
@@ -494,6 +497,12 @@ static void preempt_rebind_work_func(struct work_struct *w)
xe_assert(vm->xe, xe_vm_in_preempt_fence_mode(vm));
trace_xe_vm_rebind_worker_enter(vm);
+ /*
+ * This blocks the wq during suspend / hibernate.
+ * Don't hold any locks.
+ */
+retry_pm:
+ wait_for_completion(&vm->xe->pm_block);
down_write(&vm->lock);
if (xe_vm_is_closed_or_banned(vm)) {
@@ -503,6 +512,11 @@ static void preempt_rebind_work_func(struct work_struct *w)
}
retry:
+ if (!try_wait_for_completion(&vm->xe->pm_block)) {
+ up_write(&vm->lock);
+ goto retry_pm;
+ }
+
if (xe_vm_userptr_check_repin(vm)) {
err = xe_vm_userptr_pin(vm);
if (err)
--
2.50.1