UBUNTU-CVE-2025-40037

In the Linux kernel, the following vulnerability has been resolved: fbdev: simplefb: Fix use after free in simplefb_detach_genpds() The pm_domain cleanup can not be devres managed as it uses struct simplefb_par which is allocated within struct fb_info by framebuffer_alloc(). This allocation is explicitly freed by unregister_framebuffer() in simplefb_remove(). Devres managed cleanup runs after the device remove call and thus can no longer access struct simplefb_par. Call simplefb_detach_genpds() explicitly from simplefb_destroy() like the cleanup functions for clocks and regulators. Fixes an use after free on M2 Mac mini during aperture_remove_conflicting_devices() using the downstream asahi kernel with Debian's kernel config. For unknown reasons this started to consistently dereference an invalid pointer in v6.16.3 based kernels. [ 6.736134] BUG: KASAN: slab-use-after-free in simplefb_detach_genpds+0x58/0x220 [ 6.743545] Read of size 4 at addr ffff8000304743f0 by task (udev-worker)/227 [ 6.750697] [ 6.752182] CPU: 6 UID: 0 PID: 227 Comm: (udev-worker) Tainted: G S 6.16.3-asahi+ #16 PREEMPTLAZY [ 6.752186] Tainted: [S]=CPU_OUT_OF_SPEC [ 6.752187] Hardware name: Apple Mac mini (M2, 2023) (DT) [ 6.752189] Call trace: [ 6.752190] show_stack+0x34/0x98 (C) [ 6.752194] dump_stack_lvl+0x60/0x80 [ 6.752197] print_report+0x17c/0x4d8 [ 6.752201] kasan_report+0xb4/0x100 [ 6.752206] __asan_report_load4_noabort+0x20/0x30 [ 6.752209] simplefb_detach_genpds+0x58/0x220 [ 6.752213] devm_action_release+0x50/0x98 [ 6.752216] release_nodes+0xd0/0x2c8 [ 6.752219] devres_release_all+0xfc/0x178 [ 6.752221] device_unbind_cleanup+0x28/0x168 [ 6.752224] device_release_driver_internal+0x34c/0x470 [ 6.752228] device_release_driver+0x20/0x38 [ 6.752231] bus_remove_device+0x1b0/0x380 [ 6.752234] device_del+0x314/0x820 [ 6.752238] platform_device_del+0x3c/0x1e8 [ 6.752242]...