[PATCH 1/2] qxl: fix qxl_release_{map,unmap}

From: Gerd Hoffmann
Date: Wed Apr 18 2018 - 01:43:11 EST


s/PAGE_SIZE/PAGE_MASK/

Luckily release_offset is never larger than PAGE_SIZE, so the bug has no
bad side effects and managed to stay unnoticed for years that way ...

Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
---
drivers/gpu/drm/qxl/qxl_ioctl.c | 4 ++--
drivers/gpu/drm/qxl/qxl_release.c | 6 +++---
2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/qxl/qxl_ioctl.c b/drivers/gpu/drm/qxl/qxl_ioctl.c
index e238a1a2ec..6cc9f3367f 100644
--- a/drivers/gpu/drm/qxl/qxl_ioctl.c
+++ b/drivers/gpu/drm/qxl/qxl_ioctl.c
@@ -182,9 +182,9 @@ static int qxl_process_single_command(struct qxl_device *qdev,
goto out_free_reloc;

/* TODO copy slow path code from i915 */
- fb_cmd = qxl_bo_kmap_atomic_page(qdev, cmd_bo, (release->release_offset & PAGE_SIZE));
+ fb_cmd = qxl_bo_kmap_atomic_page(qdev, cmd_bo, (release->release_offset & PAGE_MASK));
unwritten = __copy_from_user_inatomic_nocache
- (fb_cmd + sizeof(union qxl_release_info) + (release->release_offset & ~PAGE_SIZE),
+ (fb_cmd + sizeof(union qxl_release_info) + (release->release_offset & ~PAGE_MASK),
u64_to_user_ptr(cmd->command), cmd->command_size);

{
diff --git a/drivers/gpu/drm/qxl/qxl_release.c b/drivers/gpu/drm/qxl/qxl_release.c
index 5d84a66fed..a0b4244d28 100644
--- a/drivers/gpu/drm/qxl/qxl_release.c
+++ b/drivers/gpu/drm/qxl/qxl_release.c
@@ -411,10 +411,10 @@ union qxl_release_info *qxl_release_map(struct qxl_device *qdev,
struct qxl_bo_list *entry = list_first_entry(&release->bos, struct qxl_bo_list, tv.head);
struct qxl_bo *bo = to_qxl_bo(entry->tv.bo);

- ptr = qxl_bo_kmap_atomic_page(qdev, bo, release->release_offset & PAGE_SIZE);
+ ptr = qxl_bo_kmap_atomic_page(qdev, bo, release->release_offset & PAGE_MASK);
if (!ptr)
return NULL;
- info = ptr + (release->release_offset & ~PAGE_SIZE);
+ info = ptr + (release->release_offset & ~PAGE_MASK);
return info;
}

@@ -426,7 +426,7 @@ void qxl_release_unmap(struct qxl_device *qdev,
struct qxl_bo *bo = to_qxl_bo(entry->tv.bo);
void *ptr;

- ptr = ((void *)info) - (release->release_offset & ~PAGE_SIZE);
+ ptr = ((void *)info) - (release->release_offset & ~PAGE_MASK);
qxl_bo_kunmap_atomic_page(qdev, bo, ptr);
}

--
2.9.3