diff options
| author | Chris Wilson <chris@chris-wilson.co.uk> | 2016-11-29 12:02:17 +0000 |
|---|---|---|
| committer | Sean Paul <seanpaul@chromium.org> | 2016-11-29 15:52:32 -0500 |
| commit | a53ca63502e62ca459de32821753c8227dc94197 (patch) | |
| tree | 215d63accb417972f11dc0f3654c6accd96c525e /drivers/gpu/drm/drm_fb_helper.c | |
| parent | 64e94407fb5a4128636c2b15b38fa6e71a427228 (diff) | |
drm: Protect fb_helper list manipulation with a mutex
Though we only walk the kernel_fb_helper_list inside a panic (or single
thread debugging), we still need to protect the list manipulation on
creating/removing a framebuffer device in order to prevent list
corruption.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: http://patchwork.freedesktop.org/patch/msgid/20161129120217.7344-3-chris@chris-wilson.co.uk
Diffstat (limited to 'drivers/gpu/drm/drm_fb_helper.c')
| -rw-r--r-- | drivers/gpu/drm/drm_fb_helper.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c index 90da28d2fcf3..e934b541feea 100644 --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -49,6 +49,7 @@ MODULE_PARM_DESC(fbdev_emulation, "Enable legacy fbdev emulation [default=true]"); static LIST_HEAD(kernel_fb_helper_list); +static DEFINE_MUTEX(kernel_fb_helper_lock); /** * DOC: fbdev helpers @@ -855,12 +856,14 @@ void drm_fb_helper_fini(struct drm_fb_helper *fb_helper) if (!drm_fbdev_emulation) return; + mutex_lock(&kernel_fb_helper_lock); if (!list_empty(&fb_helper->kernel_fb_list)) { list_del(&fb_helper->kernel_fb_list); if (list_empty(&kernel_fb_helper_list)) { unregister_sysrq_key('v', &sysrq_drm_fb_helper_restore_op); } } + mutex_unlock(&kernel_fb_helper_lock); drm_fb_helper_crtc_free(fb_helper); @@ -2258,10 +2261,12 @@ int drm_fb_helper_initial_config(struct drm_fb_helper *fb_helper, int bpp_sel) dev_info(dev->dev, "fb%d: %s frame buffer device\n", info->node, info->fix.id); + mutex_lock(&kernel_fb_helper_lock); if (list_empty(&kernel_fb_helper_list)) register_sysrq_key('v', &sysrq_drm_fb_helper_restore_op); list_add(&fb_helper->kernel_fb_list, &kernel_fb_helper_list); + mutex_unlock(&kernel_fb_helper_lock); return 0; } |