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/alpha/math-emu/sfp-util.h | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) create mode 100644 arch/alpha/math-emu/sfp-util.h (limited to 'arch/alpha/math-emu/sfp-util.h') diff --git a/arch/alpha/math-emu/sfp-util.h b/arch/alpha/math-emu/sfp-util.h new file mode 100644 index 000000000..ae30f3417 --- /dev/null +++ b/arch/alpha/math-emu/sfp-util.h @@ -0,0 +1,36 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#include +#include +#include +#include +#include + +#define add_ssaaaa(sh, sl, ah, al, bh, bl) \ + ((sl) = (al) + (bl), (sh) = (ah) + (bh) + ((sl) < (al))) + +#define sub_ddmmss(sh, sl, ah, al, bh, bl) \ + ((sl) = (al) - (bl), (sh) = (ah) - (bh) - ((al) < (bl))) + +#define umul_ppmm(wh, wl, u, v) \ + __asm__ ("mulq %2,%3,%1; umulh %2,%3,%0" \ + : "=r" ((UDItype)(wh)), \ + "=&r" ((UDItype)(wl)) \ + : "r" ((UDItype)(u)), \ + "r" ((UDItype)(v))) + +#define udiv_qrnnd(q, r, n1, n0, d) \ + do { unsigned long __r; \ + (q) = __udiv_qrnnd (&__r, (n1), (n0), (d)); \ + (r) = __r; \ + } while (0) +extern unsigned long __udiv_qrnnd (unsigned long *, unsigned long, + unsigned long , unsigned long); + +#define UDIV_NEEDS_NORMALIZATION 1 + +#define abort() goto bad_insn + +#ifndef __LITTLE_ENDIAN +#define __LITTLE_ENDIAN -1 +#endif +#define __BYTE_ORDER __LITTLE_ENDIAN -- cgit v1.3.1