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/hyperv/hvgdk_ext.h | 46 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+) create mode 100644 include/hyperv/hvgdk_ext.h (limited to 'include/hyperv/hvgdk_ext.h') diff --git a/include/hyperv/hvgdk_ext.h b/include/hyperv/hvgdk_ext.h new file mode 100644 index 000000000..641b591ee --- /dev/null +++ b/include/hyperv/hvgdk_ext.h @@ -0,0 +1,46 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Type definitions for the Microsoft Hypervisor. + */ +#ifndef _HV_HVGDK_EXT_H +#define _HV_HVGDK_EXT_H + +#include "hvgdk_mini.h" + +/* Extended hypercalls */ +#define HV_EXT_CALL_QUERY_CAPABILITIES 0x8001 +#define HV_EXT_CALL_MEMORY_HEAT_HINT 0x8003 + +/* Extended hypercalls */ +enum { /* HV_EXT_CALL */ + HV_EXTCALL_QUERY_CAPABILITIES = 0x8001, + HV_EXTCALL_MEMORY_HEAT_HINT = 0x8003, +}; + +/* HV_EXT_OUTPUT_QUERY_CAPABILITIES */ +#define HV_EXT_CAPABILITY_MEMORY_COLD_DISCARD_HINT BIT(8) + +enum { /* HV_EXT_MEMORY_HEAT_HINT_TYPE */ + HV_EXTMEM_HEAT_HINT_COLD = 0, + HV_EXTMEM_HEAT_HINT_HOT = 1, + HV_EXTMEM_HEAT_HINT_COLD_DISCARD = 2, + HV_EXTMEM_HEAT_HINT_MAX +}; + +/* + * The whole argument should fit in a page to be able to pass to the hypervisor + * in one hypercall. + */ +#define HV_MEMORY_HINT_MAX_GPA_PAGE_RANGES \ + ((HV_HYP_PAGE_SIZE - sizeof(struct hv_memory_hint)) / \ + sizeof(union hv_gpa_page_range)) + +/* HvExtCallMemoryHeatHint hypercall */ +#define HV_EXT_MEMORY_HEAT_HINT_TYPE_COLD_DISCARD 2 +struct hv_memory_hint { /* HV_EXT_INPUT_MEMORY_HEAT_HINT */ + u64 heat_type : 2; /* HV_EXTMEM_HEAT_HINT_* */ + u64 reserved : 62; + union hv_gpa_page_range ranges[]; +} __packed; + +#endif /* _HV_HVGDK_EXT_H */ -- cgit v1.3.1