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/powerpc/boot/fsl-soc.c | 54 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) create mode 100644 arch/powerpc/boot/fsl-soc.c (limited to 'arch/powerpc/boot/fsl-soc.c') diff --git a/arch/powerpc/boot/fsl-soc.c b/arch/powerpc/boot/fsl-soc.c new file mode 100644 index 000000000..01bad8ea6 --- /dev/null +++ b/arch/powerpc/boot/fsl-soc.c @@ -0,0 +1,54 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Freescale SOC support functions + * + * Author: Scott Wood + * + * Copyright (c) 2007 Freescale Semiconductor, Inc. + */ + +#include "ops.h" +#include "types.h" +#include "fsl-soc.h" +#include "stdio.h" + +static u32 prop_buf[MAX_PROP_LEN / 4]; + +u32 *fsl_get_immr(void) +{ + void *soc; + unsigned long ret = 0; + + soc = find_node_by_devtype(NULL, "soc"); + if (soc) { + int size; + u32 naddr; + + size = getprop(soc, "#address-cells", prop_buf, MAX_PROP_LEN); + if (size == 4) + naddr = prop_buf[0]; + else + naddr = 2; + + if (naddr != 1 && naddr != 2) + goto err; + + size = getprop(soc, "ranges", prop_buf, MAX_PROP_LEN); + + if (size < 12) + goto err; + if (prop_buf[0] != 0) + goto err; + if (naddr == 2 && prop_buf[1] != 0) + goto err; + + if (!dt_xlate_addr(soc, prop_buf + naddr, 8, &ret)) + ret = 0; + } + +err: + if (!ret) + printf("fsl_get_immr: Failed to find immr base\r\n"); + + return (u32 *)ret; +} -- cgit v1.3.1