From: Manfred Schlaegl Date: Fri, 17 Apr 2015 09:48:02 +0000 Subject: [PATCH] video/logo: fix use logo after free prevention Message-Id: <5530D6D2.8080103@gmx.at> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Jean-Christophe Plagniol-Villard , Tomi Valkeinen Cc: Manfred Schlaegl , linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org, Manfred Schlaegl After 92b004d1aa9f367c372511ca0330f58216b25703 the logos disappeared on Freescale i.MX53 and i.MX6 SoC's (detected on linux-3.12.37). This happens because the fb_find_logo function is validly called (initdata still not freed) AFTER newly introduced latecall fb_logo_late_init. Instead of stetting a logos_freed flag somewhere in lateinit, this patch uses system_state=SYSTEM_BOOTING as indication for valid initdata. Signed-off-by: Manfred Schlaegl --- drivers/video/logo/logo.c | 21 +++++---------------- 1 file changed, 5 insertions(+), 16 deletions(-) diff --git a/drivers/video/logo/logo.c b/drivers/video/logo/logo.c index 10fbfd8..ad37561 100644 --- a/drivers/video/logo/logo.c +++ b/drivers/video/logo/logo.c @@ -21,21 +21,6 @@ static bool nologo; module_param(nologo, bool, 0); MODULE_PARM_DESC(nologo, "Disables startup logo"); -/* - * Logos are located in the initdata, and will be freed in kernel_init. - * Use late_init to mark the logos as freed to prevent any further use. - */ - -static bool logos_freed; - -static int __init fb_logo_late_init(void) -{ - logos_freed = true; - return 0; -} - -late_initcall(fb_logo_late_init); - /* logo's are marked __initdata. Use __init_refok to tell * modpost that it is intended that this function uses data * marked __initdata. @@ -44,7 +29,11 @@ const struct linux_logo * __init_refok fb_find_logo(int depth) { const struct linux_logo *logo = NULL; - if (nologo || logos_freed) + /* + * Logos are located in the initdata, and will be freed in kernel_init. + * Use system_state to determine, if initdata is still useable. + */ + if (nologo || system_state != SYSTEM_BOOTING) return NULL; if (depth >= 1) { -- 1.7.10.4