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 --- include/uapi/asm-generic/swab.h | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) create mode 100644 include/uapi/asm-generic/swab.h (limited to 'include/uapi/asm-generic/swab.h') diff --git a/include/uapi/asm-generic/swab.h b/include/uapi/asm-generic/swab.h new file mode 100644 index 000000000..f2da4e4fd --- /dev/null +++ b/include/uapi/asm-generic/swab.h @@ -0,0 +1,19 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +#ifndef _ASM_GENERIC_SWAB_H +#define _ASM_GENERIC_SWAB_H + +#include + +/* + * 32 bit architectures typically (but not always) want to + * set __SWAB_64_THRU_32__. In user space, this is only + * valid if the compiler supports 64 bit data types. + */ + +#if __BITS_PER_LONG == 32 +#if defined(__GNUC__) && !defined(__STRICT_ANSI__) || defined(__KERNEL__) +#define __SWAB_64_THRU_32__ +#endif +#endif + +#endif /* _ASM_GENERIC_SWAB_H */ -- cgit v1.3.1