From 6668ed271eaefaa63e686bdfbedaeb7b8e492722 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 4 Sep 2026 10:43:19 +0200 Subject: selftests/bpf: Reject graph kptr use after RCU unlock Add a sleepable verifier test that loads a graph-node local kptr in an explicit RCU read-side critical section, then passes its node to bpf_rbtree_remove() after the section ends. Before the verifier fix, the stale NON_OWN_REF flag makes the node look like a live borrowed reference and the program is accepted. After the fix, the pointer is demoted without NON_OWN_REF and the graph kfunc argument is rejected. Also exercise a graph kptr loaded while a spin lock provides implicit RCU protection. The pointer must be invalidated when the lock is released, which guards the required ordering between non-owning-reference invalidation and RCU demotion. Update the existing fault-protected load test state description. The post-unlock pointer no longer carries NON_OWN_REF, but remains readable because the load is rewritten to use BPF_PROBE_MEM. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- drivers/video/logo/logo.c | 68 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 68 insertions(+) create mode 100644 drivers/video/logo/logo.c (limited to 'drivers/video/logo/logo.c') diff --git a/drivers/video/logo/logo.c b/drivers/video/logo/logo.c new file mode 100644 index 000000000..91535f884 --- /dev/null +++ b/drivers/video/logo/logo.c @@ -0,0 +1,68 @@ +// SPDX-License-Identifier: GPL-2.0-only + +/* + * Linux logo to be displayed on boot + * + * Copyright (C) 1996 Larry Ewing (lewing@isc.tamu.edu) + * Copyright (C) 1996,1998 Jakub Jelinek (jj@sunsite.mff.cuni.cz) + * Copyright (C) 2001 Greg Banks + * Copyright (C) 2001 Jan-Benedict Glaw + * Copyright (C) 2003 Geert Uytterhoeven + */ + +#include +#include +#include + +#ifdef CONFIG_M68K +#include +#endif + +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_sync(fb_logo_late_init); + +/* logo's are marked __initdata. Use __ref to tell + * modpost that it is intended that this function uses data + * marked __initdata. + */ +const struct linux_logo * __ref fb_find_logo(int depth) +{ + const struct linux_logo *logo = NULL; + + if (nologo || logos_freed) + return NULL; + +#ifdef CONFIG_LOGO_LINUX_MONO + if (depth >= 1) + logo = &logo_linux_mono; +#endif + +#ifdef CONFIG_LOGO_LINUX_VGA16 + if (depth >= 4) + logo = &logo_linux_vga16; +#endif + +#ifdef CONFIG_LOGO_LINUX_CLUT224 + if (depth >= 8) + logo = &logo_linux_clut224; +#endif + + return logo; +} +EXPORT_SYMBOL_GPL(fb_find_logo); -- cgit v1.3.1