This is a note to let you know that I've just added the patch titled drm: Fix potential null-ptr-deref due to drmm_mode_config_init() to the 5.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: drm-fix-potential-null-ptr-deref-due-to-drmm_mode_co.patch and it can be found in the queue-5.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 04f3f481b5c7b3235bbe57dcdb35595979d2957d Author: Shang XiaoJing <shangxiaojing@xxxxxxxxxx> Date: Fri Nov 18 10:16:51 2022 +0800 drm: Fix potential null-ptr-deref due to drmm_mode_config_init() [ Upstream commit 834c23e4f798dcdc8af251b3c428ceef94741991 ] drmm_mode_config_init() will call drm_mode_create_standard_properties() and won't check the ret value. When drm_mode_create_standard_properties() failed due to alloc, property will be a NULL pointer and may causes the null-ptr-deref. Fix the null-ptr-deref by adding the ret value check. Found null-ptr-deref while testing insert module bochs: general protection fault, probably for non-canonical address 0xdffffc000000000c: 0000 [#1] SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000060-0x0000000000000067] CPU: 3 PID: 249 Comm: modprobe Not tainted 6.1.0-rc1+ #364 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014 RIP: 0010:drm_object_attach_property+0x73/0x3c0 [drm] Call Trace: <TASK> __drm_connector_init+0xb6c/0x1100 [drm] bochs_pci_probe.cold.11+0x4cb/0x7fe [bochs] pci_device_probe+0x17d/0x340 really_probe+0x1db/0x5d0 __driver_probe_device+0x1e7/0x250 driver_probe_device+0x4a/0x120 __driver_attach+0xcd/0x2c0 bus_for_each_dev+0x11a/0x1b0 bus_add_driver+0x3d7/0x500 driver_register+0x18e/0x320 do_one_initcall+0xc4/0x3e0 do_init_module+0x1b4/0x630 load_module+0x5dca/0x7230 __do_sys_finit_module+0x100/0x170 do_syscall_64+0x3f/0x90 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7ff65af9f839 Fixes: 6b4959f43a04 ("drm/atomic: atomic plane properties") Signed-off-by: Shang XiaoJing <shangxiaojing@xxxxxxxxxx> Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx> Link: https://patchwork.freedesktop.org/patch/msgid/20221118021651.2460-1-shangxiaojing@xxxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c index 37b4b9f0e468a..1bd4f0b2cc4d3 100644 --- a/drivers/gpu/drm/drm_mode_config.c +++ b/drivers/gpu/drm/drm_mode_config.c @@ -398,6 +398,8 @@ static void drm_mode_config_init_release(struct drm_device *dev, void *ptr) */ int drmm_mode_config_init(struct drm_device *dev) { + int ret; + mutex_init(&dev->mode_config.mutex); drm_modeset_lock_init(&dev->mode_config.connection_mutex); mutex_init(&dev->mode_config.idr_mutex); @@ -419,7 +421,11 @@ int drmm_mode_config_init(struct drm_device *dev) init_llist_head(&dev->mode_config.connector_free_list); INIT_WORK(&dev->mode_config.connector_free_work, drm_connector_free_work_fn); - drm_mode_create_standard_properties(dev); + ret = drm_mode_create_standard_properties(dev); + if (ret) { + drm_mode_config_cleanup(dev); + return ret; + } /* Just to be sure */ dev->mode_config.num_fb = 0;