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/sysdev/6xx-suspend.S | 48 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) create mode 100644 arch/powerpc/sysdev/6xx-suspend.S (limited to 'arch/powerpc/sysdev/6xx-suspend.S') diff --git a/arch/powerpc/sysdev/6xx-suspend.S b/arch/powerpc/sysdev/6xx-suspend.S new file mode 100644 index 000000000..e882524ff --- /dev/null +++ b/arch/powerpc/sysdev/6xx-suspend.S @@ -0,0 +1,48 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Enter and leave sleep state on chips with 6xx-style HID0 + * power management bits, which don't leave sleep state via reset. + * + * Author: Scott Wood + * + * Copyright (c) 2006-2007 Freescale Semiconductor, Inc. + */ + +#include +#include +#include +#include + +_GLOBAL(mpc6xx_enter_standby) + mflr r4 + + mfspr r5, SPRN_HID0 + rlwinm r5, r5, 0, ~(HID0_DOZE | HID0_NAP) + oris r5, r5, HID0_SLEEP@h + mtspr SPRN_HID0, r5 + isync + + lis r5, ret_from_standby@h + ori r5, r5, ret_from_standby@l + mtlr r5 + + lwz r6, TI_LOCAL_FLAGS(r2) + ori r6, r6, _TLF_SLEEPING + stw r6, TI_LOCAL_FLAGS(r2) + + mfmsr r5 + ori r5, r5, MSR_EE + oris r5, r5, MSR_POW@h + sync + mtmsr r5 + isync + +1: b 1b + +ret_from_standby: + mfspr r5, SPRN_HID0 + rlwinm r5, r5, 0, ~HID0_SLEEP + mtspr SPRN_HID0, r5 + + mtlr r4 + blr -- cgit v1.3.1