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 --- scripts/include/xalloc.h | 53 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) create mode 100644 scripts/include/xalloc.h (limited to 'scripts/include/xalloc.h') diff --git a/scripts/include/xalloc.h b/scripts/include/xalloc.h new file mode 100644 index 000000000..cdadb07d0 --- /dev/null +++ b/scripts/include/xalloc.h @@ -0,0 +1,53 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +#ifndef XALLOC_H +#define XALLOC_H + +#include +#include + +static inline void *xmalloc(size_t size) +{ + void *p = malloc(size); + + if (!p) + exit(1); + return p; +} + +static inline void *xcalloc(size_t nmemb, size_t size) +{ + void *p = calloc(nmemb, size); + + if (!p) + exit(1); + return p; +} + +static inline void *xrealloc(void *p, size_t size) +{ + p = realloc(p, size); + if (!p) + exit(1); + return p; +} + +static inline char *xstrdup(const char *s) +{ + char *p = strdup(s); + + if (!p) + exit(1); + return p; +} + +static inline char *xstrndup(const char *s, size_t n) +{ + char *p = strndup(s, n); + + if (!p) + exit(1); + return p; +} + +#endif /* XALLOC_H */ -- cgit v1.3.1