From: Shuicheng Lin Date: Thu, 25 Jun 2026 21:56:15 +0000 (+0000) Subject: drm/xe/userptr: Hold notifier_lock for write on inject test path X-Git-Tag: v7.2-rc2~10^2~1^2~6 X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=dca6e08c923a44d2d66b955e03dd57a3a38c2b94;p=thirdparty%2Flinux.git drm/xe/userptr: Hold notifier_lock for write on inject test path When CONFIG_DRM_XE_USERPTR_INVAL_INJECT=y, xe_pt_svm_userptr_pre_commit() runs vma_check_userptr() with the svm notifier_lock taken for read. The test injection causes vma_check_userptr() to call xe_vma_userptr_force_invalidate(), which feeds into xe_vma_userptr_do_inval() with drm_gpusvm_ctx.in_notifier=true. That flag tells drm_gpusvm_unmap_pages() the caller already holds notifier_lock for write and only asserts the mode. Because the caller actually holds it for read, the assertion fires: WARNING: drivers/gpu/drm/drm_gpusvm.c:1669 at \ drm_gpusvm_unmap_pages+0xd4/0x130 [drm_gpusvm_helper] Call Trace: xe_vma_userptr_do_inval+0x40d/0xfd0 [xe] xe_vma_userptr_invalidate_pass1+0x3e6/0x8d0 [xe] xe_vma_userptr_force_invalidate+0xde/0x290 [xe] vma_check_userptr.constprop.0+0x1c6/0x220 [xe] xe_pt_svm_userptr_pre_commit+0x6a3/0xc60 [xe] ... xe_vm_bind_ioctl+0x3a0a/0x4480 [xe] Acquire notifier_lock for write in pre-commit when the inject Kconfig is enabled, via new helpers xe_pt_svm_userptr_notifier_lock()/_unlock(). Rename xe_svm_assert_held_read() to xe_svm_assert_held_read_or_inject_write() so it asserts the correct mode under each build configuration. Production builds (CONFIG_DRM_XE_USERPTR_INVAL_INJECT=n) keep the existing read-mode behavior bit-for-bit. Fixes: 9e9787414882 ("drm/xe/userptr: replace xe_hmm with gpusvm") Assisted-by: Claude:claude-opus-4.7 Cc: Matthew Auld Cc: Zongyao Bai Reviewed-by: Matthew Brost Link: https://patch.msgid.link/20260625215615.3016892-1-shuicheng.lin@intel.com Signed-off-by: Shuicheng Lin (cherry picked from commit 80ccbd97ffee8ad2e73167d826fe7be548364365) Signed-off-by: Thomas Hellström --- diff --git a/drivers/gpu/drm/xe/xe_pt.c b/drivers/gpu/drm/xe/xe_pt.c index 234ea175c5e3..3380ce710a48 100644 --- a/drivers/gpu/drm/xe/xe_pt.c +++ b/drivers/gpu/drm/xe/xe_pt.c @@ -1086,7 +1086,7 @@ static void xe_pt_commit_locks_assert(struct xe_vma *vma) xe_pt_commit_prepare_locks_assert(vma); if (xe_vma_is_userptr(vma)) - xe_svm_assert_held_read(vm); + xe_svm_assert_held_read_or_inject_write(vm); } static void xe_pt_commit(struct xe_vma *vma, @@ -1406,6 +1406,33 @@ static int xe_pt_pre_commit(struct xe_migrate_pt_update *pt_update) pt_update_ops, rftree); } +/* + * Acquire/release the svm notifier_lock around xe_pt_svm_userptr_pre_commit() + * and the matching late release in xe_pt_update_ops_run(). Read mode by + * default; write mode when CONFIG_DRM_XE_USERPTR_INVAL_INJECT is on, + * because a userptr op in this critical section may invoke the injected + * xe_vma_userptr_force_invalidate() path that calls + * drm_gpusvm_unmap_pages() with ctx->in_notifier=true, which requires the + * lock held for write. + */ +static void xe_pt_svm_userptr_notifier_lock(struct xe_vm *vm) +{ +#if IS_ENABLED(CONFIG_DRM_XE_USERPTR_INVAL_INJECT) + down_write(&vm->svm.gpusvm.notifier_lock); +#else + xe_svm_notifier_lock(vm); +#endif +} + +static void xe_pt_svm_userptr_notifier_unlock(struct xe_vm *vm) +{ +#if IS_ENABLED(CONFIG_DRM_XE_USERPTR_INVAL_INJECT) + up_write(&vm->svm.gpusvm.notifier_lock); +#else + xe_svm_notifier_unlock(vm); +#endif +} + #if IS_ENABLED(CONFIG_DRM_GPUSVM) #ifdef CONFIG_DRM_XE_USERPTR_INVAL_INJECT @@ -1437,7 +1464,7 @@ static int vma_check_userptr(struct xe_vm *vm, struct xe_vma *vma, struct xe_userptr_vma *uvma; unsigned long notifier_seq; - xe_svm_assert_held_read(vm); + xe_svm_assert_held_read_or_inject_write(vm); if (!xe_vma_is_userptr(vma)) return 0; @@ -1467,7 +1494,7 @@ static int op_check_svm_userptr(struct xe_vm *vm, struct xe_vma_op *op, { int err = 0; - xe_svm_assert_held_read(vm); + xe_svm_assert_held_read_or_inject_write(vm); switch (op->base.op) { case DRM_GPUVA_OP_MAP: @@ -1539,12 +1566,12 @@ static int xe_pt_svm_userptr_pre_commit(struct xe_migrate_pt_update *pt_update) if (err) return err; - xe_svm_notifier_lock(vm); + xe_pt_svm_userptr_notifier_lock(vm); list_for_each_entry(op, &vops->list, link) { err = op_check_svm_userptr(vm, op, pt_update_ops); if (err) { - xe_svm_notifier_unlock(vm); + xe_pt_svm_userptr_notifier_unlock(vm); break; } } @@ -2403,7 +2430,7 @@ static void bind_op_commit(struct xe_vm *vm, struct xe_tile *tile, vma->tile_invalidated & ~BIT(tile->id)); vma->tile_staged &= ~BIT(tile->id); if (xe_vma_is_userptr(vma)) { - xe_svm_assert_held_read(vm); + xe_svm_assert_held_read_or_inject_write(vm); to_userptr_vma(vma)->userptr.initial_bind = true; } @@ -2439,7 +2466,7 @@ static void unbind_op_commit(struct xe_vm *vm, struct xe_tile *tile, if (!vma->tile_present) { list_del_init(&vma->combined_links.rebind); if (xe_vma_is_userptr(vma)) { - xe_svm_assert_held_read(vm); + xe_svm_assert_held_read_or_inject_write(vm); spin_lock(&vm->userptr.invalidated_lock); list_del_init(&to_userptr_vma(vma)->userptr.invalidate_link); @@ -2715,7 +2742,7 @@ xe_pt_update_ops_run(struct xe_tile *tile, struct xe_vma_ops *vops) } if (pt_update_ops->needs_svm_lock) - xe_svm_notifier_unlock(vm); + xe_pt_svm_userptr_notifier_unlock(vm); /* * The last fence is only used for zero bind queue idling; migrate diff --git a/drivers/gpu/drm/xe/xe_svm.h b/drivers/gpu/drm/xe/xe_svm.h index b7b8eeacf196..3ca46a6f98c7 100644 --- a/drivers/gpu/drm/xe/xe_svm.h +++ b/drivers/gpu/drm/xe/xe_svm.h @@ -394,8 +394,19 @@ static inline struct drm_pagemap *xe_drm_pagemap_from_fd(int fd, u32 region_inst #define xe_svm_assert_in_notifier(vm__) \ lockdep_assert_held_write(&(vm__)->svm.gpusvm.notifier_lock) -#define xe_svm_assert_held_read(vm__) \ +/* + * Assert the svm notifier_lock is held. Read mode by default; write mode + * when CONFIG_DRM_XE_USERPTR_INVAL_INJECT is on, because that path forces + * a userptr invalidation that ends in drm_gpusvm_unmap_pages() with + * ctx->in_notifier=true, which requires the lock held for write. + */ +#if IS_ENABLED(CONFIG_DRM_XE_USERPTR_INVAL_INJECT) +#define xe_svm_assert_held_read_or_inject_write(vm__) \ + lockdep_assert_held_write(&(vm__)->svm.gpusvm.notifier_lock) +#else +#define xe_svm_assert_held_read_or_inject_write(vm__) \ lockdep_assert_held_read(&(vm__)->svm.gpusvm.notifier_lock) +#endif #define xe_svm_notifier_lock(vm__) \ drm_gpusvm_notifier_lock(&(vm__)->svm.gpusvm) @@ -409,7 +420,7 @@ static inline struct drm_pagemap *xe_drm_pagemap_from_fd(int fd, u32 region_inst #else #define xe_svm_assert_in_notifier(...) do {} while (0) -static inline void xe_svm_assert_held_read(struct xe_vm *vm) +static inline void xe_svm_assert_held_read_or_inject_write(struct xe_vm *vm) { }