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 --- arch/arm/mach-s3c/cpu.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) create mode 100644 arch/arm/mach-s3c/cpu.c (limited to 'arch/arm/mach-s3c/cpu.c') diff --git a/arch/arm/mach-s3c/cpu.c b/arch/arm/mach-s3c/cpu.c new file mode 100644 index 000000000..3491f790d --- /dev/null +++ b/arch/arm/mach-s3c/cpu.c @@ -0,0 +1,32 @@ +// SPDX-License-Identifier: GPL-2.0 +// +// Copyright (c) 2009-2011 Samsung Electronics Co., Ltd. +// http://www.samsung.com +// +// Samsung CPU Support + +#include +#include +#include +#include + +#include "map-base.h" +#include "cpu.h" + +unsigned long samsung_cpu_id; + +void __init s3c64xx_init_cpu(void) +{ + samsung_cpu_id = readl_relaxed(S3C_VA_SYS + 0x118); + if (!samsung_cpu_id) { + /* + * S3C6400 has the ID register in a different place, + * and needs a write before it can be read. + */ + writel_relaxed(0x0, S3C_VA_SYS + 0xA1C); + samsung_cpu_id = readl_relaxed(S3C_VA_SYS + 0xA1C); + } + + pr_info("Samsung CPU ID: 0x%08lx\n", samsung_cpu_id); + pr_err("The platform is deprecated and scheduled for removal. Please reach to the maintainers of the platform and linux-samsung-soc@vger.kernel.org if you still use it. Without such feedback, the platform will be removed after 2022.\n"); +} -- cgit v1.3.1