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/m68k/tools/amiga/Makefile | 12 ++++++++ arch/m68k/tools/amiga/dmesg.c | 69 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 81 insertions(+) create mode 100644 arch/m68k/tools/amiga/Makefile create mode 100644 arch/m68k/tools/amiga/dmesg.c (limited to 'arch/m68k/tools') diff --git a/arch/m68k/tools/amiga/Makefile b/arch/m68k/tools/amiga/Makefile new file mode 100644 index 000000000..e6425b367 --- /dev/null +++ b/arch/m68k/tools/amiga/Makefile @@ -0,0 +1,12 @@ +# SPDX-License-Identifier: GPL-2.0 + +CC = m68k-cbm-amigados-gcc +CFLAGS = -Wall -O2 + + +All: dmesg + + +dmesg: dmesg.c + $(CC) $(CFLAGS) -o dmesg dmesg.c -noixemul + diff --git a/arch/m68k/tools/amiga/dmesg.c b/arch/m68k/tools/amiga/dmesg.c new file mode 100644 index 000000000..f8005a7ef --- /dev/null +++ b/arch/m68k/tools/amiga/dmesg.c @@ -0,0 +1,69 @@ +/* + * linux/arch/m68k/tools/amiga/dmesg.c -- Retrieve the kernel messages stored + * in Chip RAM with the kernel command + * line option `debug=mem'. + * + * © Copyright 1996 by Geert Uytterhoeven + * + * + * Usage: + * + * dmesg + * dmesg + * + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file COPYING in the main directory of the Linux + * distribution for more details. + */ + + +#include +#include +#include + + +#define CHIPMEM_START 0x00000000 +#define CHIPMEM_END 0x00200000 /* overridden by argv[1] */ + +#define SAVEKMSG_MAGIC1 0x53415645 /* 'SAVE' */ +#define SAVEKMSG_MAGIC2 0x4B4D5347 /* 'KMSG' */ + +struct savekmsg { + u_long magic1; /* SAVEKMSG_MAGIC1 */ + u_long magic2; /* SAVEKMSG_MAGIC2 */ + u_long magicptr; /* address of magic1 */ + u_long size; + char data[]; +}; + + +int main(int argc, char *argv[]) +{ + u_long start = CHIPMEM_START, end = CHIPMEM_END, p; + int found = 0; + struct savekmsg *m = NULL; + + if (argc >= 2) + end = strtoul(argv[1], NULL, 0); + printf("Searching for SAVEKMSG magic...\n"); + for (p = start; p <= end-sizeof(struct savekmsg); p += 4) { + m = (struct savekmsg *)p; + if ((m->magic1 == SAVEKMSG_MAGIC1) && (m->magic2 == SAVEKMSG_MAGIC2) && + (m->magicptr == p)) { + found = 1; + break; + } + } + if (!found) + printf("Not found\n"); + else { + printf("Found %ld bytes at 0x%08lx\n", m->size, (u_long)&m->data); + puts(">>>>>>>>>>>>>>>>>>>>"); + fflush(stdout); + write(1, &m->data, m->size); + fflush(stdout); + puts("<<<<<<<<<<<<<<<<<<<<"); + } + return(0); +} -- cgit v1.3.1