#include #include #include #include #include #include #include #include /** * get_vaddr_frames() - map virtual addresses to pfns * @start: starting user address * @nr_frames: number of pages / pfns from start to map * @gup_flags: flags modifying lookup behaviour * @vec: structure which receives pages / pfns of the addresses mapped. * It should have space for at least nr_frames entries. * * This function maps virtual addresses from @start and fills @vec structure * with page frame numbers or page pointers to corresponding pages (choice * depends on the type of the vma underlying the virtual address). If @start * belongs to a normal vma, the function grabs reference to each of the pages * to pin them in memory. If @start belongs to VM_IO | VM_PFNMAP vma, we don't * touch page structures and the caller must make sure pfns aren't reused for * anything else while he is using them. * * The function returns number of pages mapped which may be less than * @nr_frames. In particular we stop mapping if there are more vmas of * different type underlying the specified range of virtual addresses. * When the function isn't able to map a single page, it returns error. * * This function takes care of grabbing mmap_sem as necessary. */ int get_vaddr_frames(unsigned long start, unsigned int nr_frames, unsigned int gup_flags, struct frame_vector *vec) { struct mm_struct *mm = current->mm; struct vm_area_struct *vma; int ret = 0; int err; int locked; if (nr_frames == 0) return 0; if (WARN_ON_ONCE(nr_frames > vec->nr_allocated)) nr_frames = vec->nr_allocated; down_read(&mm->mmap_sem); locked = 1; vma = find_vma_intersection(mm, start, start + 1); if (!vma) { ret = -EFAULT; goto out; } if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) { vec->got_ref = true; vec->is_pfns = false; ret = get_user_pages_locked(start, nr_frames, gup_flags, (struct page **)(vec->ptrs), &locked); goto out; } vec->got_ref = false; vec->is_pfns = true; do { unsigned long *nums = frame_vector_pfns(vec); while (ret < nr_frames && start + PAGE_SIZE <= vma->vm_end) { err = follow_pfn(vma, start, &nums[ret]); if (err) { if (ret == 0) ret = err; goto out; } start += PAGE_SIZE; ret++; } /* * We stop if we have enough pages or if VMA doesn't completely * cover the tail page. */ if (ret >= nr_frames || start < vma->vm_end) break; vma = find_vma_intersection(mm, start, start + 1); } while (vma && vma->vm_flags & (VM_IO | VM_PFNMAP)); out: if (locked) up_read(&mm->mmap_sem); if (!ret) ret = -EFAULT; if (ret > 0) vec->nr_frames = ret; return ret; } EXPORT_SYMBOL(get_vaddr_frames); /** * put_vaddr_frames() - drop references to pages if get_vaddr_frames() acquired * them * @vec: frame vector to put * * Drop references to pages if get_vaddr_frames() acquired them. We also * invalidate the frame vector so that it is prepared for the next call into * get_vaddr_frames(). */ void put_vaddr_frames(struct frame_vector *vec) { int i; struct page **pages; if (!vec->got_ref) goto out; pages = frame_vector_pages(vec); /* * frame_vector_pages() might needed to do a conversion when * get_vaddr_frames() got pages but vec was later converted to pfns. * But it shouldn't really fail to convert pfns back... */ if (WARN_ON(IS_ERR(pages))) goto out; for (i = 0; i < vec->nr_frames; i++) put_page(pages[i]); vec->got_ref = false; out: vec->nr_frames = 0; } EXPORT_SYMBOL(put_vaddr_frames); /** * frame_vector_to_pages - convert frame vector to contain page pointers * @vec: frame vector to convert * * Convert @vec to contain array of page pointers. If the conversion is * successful, return 0. Otherwise return an error. Note that we do not grab * page references for the page structures. */ int frame_vector_to_pages(struct frame_vector *vec) { int i; unsigned long *nums; struct page **pages; if (!vec->is_pfns) return 0; nums = frame_vector_pfns(vec); for (i = 0; i < vec->nr_frames; i++) if (!pfn_valid(nums[i])) return -EINVAL; pages = (struct page **)nums; for (i = 0; i < vec->nr_frames; i++) pages[i] = pfn_to_page(nums[i]); vec->is_pfns = false; return 0; } EXPORT_SYMBOL(frame_vector_to_pages); /** * frame_vector_to_pfns - convert frame vector to contain pfns * @vec: frame vector to convert * * Convert @vec to contain array of pfns. */ void frame_vector_to_pfns(struct frame_vector *vec) { int i; unsigned long *nums; struct page **pages; if (vec->is_pfns) return; pages = (struct page **)(vec->ptrs); nums = (unsigned long *)pages; for (i = 0; i < vec->nr_frames; i++) nums[i] = page_to_pfn(pages[i]); vec->is_pfns = true; } EXPORT_SYMBOL(frame_vector_to_pfns); /** * frame_vector_create() - allocate & initialize structure for pinned pfns * @nr_frames: number of pfns slots we should reserve * * Allocate and initialize struct pinned_pfns to be able to hold @nr_pfns * pfns. */ struct frame_vector *frame_vector_create(unsigned int nr_frames) { struct frame_vector *vec; int size = sizeof(struct frame_vector) + sizeof(void *) * nr_frames; if (WARN_ON_ONCE(nr_frames == 0)) return NULL; /* * This is absurdly high. It's here just to avoid strange effects when * arithmetics overflows. */ if (WARN_ON_ONCE(nr_frames > INT_MAX / sizeof(void *) / 2)) return NULL; /* * Avoid higher order allocations, use vmalloc instead. It should * be rare anyway. */ if (size <= PAGE_SIZE) vec = kmalloc(size, GFP_KERNEL); else vec = vmalloc(size); if (!vec) return NULL; vec->nr_allocated = nr_frames; vec->nr_frames = 0; return vec; } EXPORT_SYMBOL(frame_vector_create); /** * frame_vector_destroy() - free memory allocated to carry frame vector * @vec: Frame vector to free * * Free structure allocated by frame_vector_create() to carry frames. */ void frame_vector_destroy(struct frame_vector *vec) { /* Make sure put_vaddr_frames() got called properly... */ VM_BUG_ON(vec->nr_frames > 0); kvfree(vec); } EXPORT_SYMBOL(frame_vector_destroy); LL, resulting in an oops immediately afterwards as the (inlined) call to i915_vma_unpin_fence() tries to dereference it. It seems to be some race condition where the object is going away at shutdown time, since both times happened when shutting down the X server. The call chains were different: - VT ioctl(KDSETMODE, KD_TEXT): intel_cleanup_plane_fb+0x5b/0xa0 [i915] drm_atomic_helper_cleanup_planes+0x6f/0x90 [drm_kms_helper] intel_atomic_commit_tail+0x749/0xfe0 [i915] intel_atomic_commit+0x3cb/0x4f0 [i915] drm_atomic_commit+0x4b/0x50 [drm] restore_fbdev_mode+0x14c/0x2a0 [drm_kms_helper] drm_fb_helper_restore_fbdev_mode_unlocked+0x34/0x80 [drm_kms_helper] drm_fb_helper_set_par+0x2d/0x60 [drm_kms_helper] intel_fbdev_set_par+0x18/0x70 [i915] fb_set_var+0x236/0x460 fbcon_blank+0x30f/0x350 do_unblank_screen+0xd2/0x1a0 vt_ioctl+0x507/0x12a0 tty_ioctl+0x355/0xc30 do_vfs_ioctl+0xa3/0x5e0 SyS_ioctl+0x79/0x90 entry_SYSCALL_64_fastpath+0x13/0x94 - i915 unpin_work workqueue: intel_unpin_work_fn+0x58/0x140 [i915] process_one_work+0x1f1/0x480 worker_thread+0x48/0x4d0 kthread+0x101/0x140 and this patch purely papers over the issue by adding a NULL pointer check and a WARN_ON_ONCE() to avoid the oops that would then generally make the machine unresponsive. Other callers of i915_gem_object_to_ggtt() seem to also check for the returned pointer being NULL and warn about it, so this clearly has happened before in other places. [ Reported it originally to the i915 developers on Jan 8, applying the ugly workaround on my own now after triggering the problem for the second time with no feedback. This is likely to be the same bug reported as https://bugs.freedesktop.org/show_bug.cgi?id=98829 https://bugs.freedesktop.org/show_bug.cgi?id=99134 which has a patch for the underlying problem, but it hasn't gotten to me, so I'm applying the workaround. ] Cc: Daniel Vetter <daniel.vetter@intel.com> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Imre Deak <imre.deak@intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/usb/dwc2/pci.c')