From 1de7259275ca4ebc66459de6620558d3e38d4142 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Noralf=20Tr=C3=B8nnes?= Date: Tue, 23 Apr 2019 16:53:53 +0200 Subject: [PATCH] drm/fb-helper: Fix drm_fb_helper_firmware_config() NULL pointer deref MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Non-atomic drivers like ast doesn't have connector->state set resulting in a NULL pointer deref: [ 29.609593] BUG: unable to handle kernel NULL pointer dereference at 0000000000000010 [ 29.609619] Call Trace: [ 29.609630] ? drm_helper_probe_single_connector_modes+0x27f/0x680 [ 29.609640] drm_setup_crtcs+0x431/0xd80 [drm_kms_helper] [ 29.753065] __drm_fb_helper_initial_config_and_unlock+0x6f/0x6a0 [ 29.753160] ? drm_modeset_unlock_all+0x31/0x50 [drm] [ 29.765758] ast_fbdev_init+0xa8/0xc0 [ast] [ 29.765762] ast_driver_load.cold.7+0x2b3/0xe11 [ast] [ 29.765775] drm_dev_register+0x111/0x150 [drm] Fix by bailing out if the driver does not support atomic modesetting. Fixes: 09ded8af57bc ("drm/i915/fbdev: Move intel_fb_initial_config() to fbdev helper") Reported-by: Thomas Zimmermann Cc: Daniel Vetter Cc: Jani Nikula Signed-off-by: Noralf Trønnes Reviewed-by: Daniel Vetter Tested-by: Thomas Zimmermann Link: https://patchwork.freedesktop.org/patch/msgid/20190423145353.30158-1-noralf@tronnes.org --- drivers/gpu/drm/drm_fb_helper.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c index 226c0910ba91..498f95c3e81d 100644 --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -2588,6 +2588,9 @@ static bool drm_fb_helper_firmware_config(struct drm_fb_helper *fb_helper, int num_connectors_detected = 0; struct drm_modeset_acquire_ctx ctx; + if (!drm_drv_uses_atomic_modeset(dev)) + return false; + save_enabled = kcalloc(count, sizeof(bool), GFP_KERNEL); if (!save_enabled) return false;