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 --- tools/lib/cmdline.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) create mode 100644 tools/lib/cmdline.c (limited to 'tools/lib/cmdline.c') diff --git a/tools/lib/cmdline.c b/tools/lib/cmdline.c new file mode 100644 index 000000000..c85f00f43 --- /dev/null +++ b/tools/lib/cmdline.c @@ -0,0 +1,53 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * From lib/cmdline.c + */ +#include + +#if __has_attribute(__fallthrough__) +# define fallthrough __attribute__((__fallthrough__)) +#else +# define fallthrough do {} while (0) /* fallthrough */ +#endif + +unsigned long long memparse(const char *ptr, char **retptr) +{ + char *endptr; /* local pointer to end of parsed string */ + + unsigned long long ret = strtoll(ptr, &endptr, 0); + + switch (*endptr) { + case 'E': + case 'e': + ret <<= 10; + fallthrough; + case 'P': + case 'p': + ret <<= 10; + fallthrough; + case 'T': + case 't': + ret <<= 10; + fallthrough; + case 'G': + case 'g': + ret <<= 10; + fallthrough; + case 'M': + case 'm': + ret <<= 10; + fallthrough; + case 'K': + case 'k': + ret <<= 10; + endptr++; + fallthrough; + default: + break; + } + + if (retptr) + *retptr = endptr; + + return ret; +} -- cgit v1.3.1