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/powerpc/boot/stdlib.c | 42 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) create mode 100644 arch/powerpc/boot/stdlib.c (limited to 'arch/powerpc/boot/stdlib.c') diff --git a/arch/powerpc/boot/stdlib.c b/arch/powerpc/boot/stdlib.c new file mode 100644 index 000000000..868b019d6 --- /dev/null +++ b/arch/powerpc/boot/stdlib.c @@ -0,0 +1,42 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * stdlib functions + * + * Author: Scott Wood + * + * Copyright (c) 2007 Freescale Semiconductor, Inc. + */ + +#include "stdlib.h" + +/* Not currently supported: leading whitespace, sign, 0x prefix, zero base */ +unsigned long long int strtoull(const char *ptr, char **end, int base) +{ + unsigned long long ret = 0; + + if (base > 36) + goto out; + + while (*ptr) { + int digit; + + if (*ptr >= '0' && *ptr <= '9' && *ptr < '0' + base) + digit = *ptr - '0'; + else if (*ptr >= 'A' && *ptr < 'A' + base - 10) + digit = *ptr - 'A' + 10; + else if (*ptr >= 'a' && *ptr < 'a' + base - 10) + digit = *ptr - 'a' + 10; + else + break; + + ret *= base; + ret += digit; + ptr++; + } + +out: + if (end) + *end = (char *)ptr; + + return ret; +} -- cgit v1.3.1