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 --- init/version.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) create mode 100644 init/version.c (limited to 'init/version.c') diff --git a/init/version.c b/init/version.c new file mode 100644 index 000000000..94c96f6fb --- /dev/null +++ b/init/version.c @@ -0,0 +1,54 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * linux/init/version.c + * + * Copyright (C) 1992 Theodore Ts'o + * + * May be freely distributed as part of Linux. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +static int __init early_hostname(char *arg) +{ + size_t bufsize = sizeof(init_uts_ns.name.nodename); + size_t maxlen = bufsize - 1; + ssize_t arglen; + + arglen = strscpy(init_uts_ns.name.nodename, arg, bufsize); + if (arglen < 0) { + pr_warn("hostname parameter exceeds %zd characters and will be truncated", + maxlen); + } + return 0; +} +early_param("hostname", early_hostname); + +const char linux_proc_banner[] = + "%s version %s" + " (" LINUX_COMPILE_BY "@" LINUX_COMPILE_HOST ")" + " (" LINUX_COMPILER ") %s\n"; + +BUILD_SALT; +BUILD_LTO_INFO; + +/* + * init_uts_ns and linux_banner contain the build version and timestamp, + * which are really fixed at the very last step of build process. + * They are compiled with __weak first, and without __weak later. + */ + +struct uts_namespace init_uts_ns __weak; +const char linux_banner[] __weak; + +#include "version-timestamp.c" + +EXPORT_SYMBOL_GPL(init_uts_ns); -- cgit v1.3.1