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/xen/arm/interface.h | 86 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 86 insertions(+) create mode 100644 include/xen/arm/interface.h (limited to 'include/xen/arm/interface.h') diff --git a/include/xen/arm/interface.h b/include/xen/arm/interface.h new file mode 100644 index 000000000..61360b89d --- /dev/null +++ b/include/xen/arm/interface.h @@ -0,0 +1,86 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/****************************************************************************** + * Guest OS interface to ARM Xen. + * + * Stefano Stabellini , Citrix, 2012 + */ + +#ifndef _ASM_ARM_XEN_INTERFACE_H +#define _ASM_ARM_XEN_INTERFACE_H + +#include + +#define uint64_aligned_t uint64_t __attribute__((aligned(8))) + +#define __DEFINE_GUEST_HANDLE(name, type) \ + typedef struct { union { type *p; uint64_aligned_t q; }; } \ + __guest_handle_ ## name + +#define DEFINE_GUEST_HANDLE_STRUCT(name) \ + __DEFINE_GUEST_HANDLE(name, struct name) +#define DEFINE_GUEST_HANDLE(name) __DEFINE_GUEST_HANDLE(name, name) +#define GUEST_HANDLE(name) __guest_handle_ ## name + +#define set_xen_guest_handle(hnd, val) \ + do { \ + if (sizeof(hnd) == 8) \ + *(uint64_t *)&(hnd) = 0; \ + (hnd).p = val; \ + } while (0) + +#define __HYPERVISOR_platform_op_raw __HYPERVISOR_platform_op + +#ifndef __ASSEMBLER__ +/* Explicitly size integers that represent pfns in the interface with + * Xen so that we can have one ABI that works for 32 and 64 bit guests. + * Note that this means that the xen_pfn_t type may be capable of + * representing pfn's which the guest cannot represent in its own pfn + * type. However since pfn space is controlled by the guest this is + * fine since it simply wouldn't be able to create any sure pfns in + * the first place. + */ +typedef uint64_t xen_pfn_t; +#define PRI_xen_pfn "llx" +typedef uint64_t xen_ulong_t; +#define PRI_xen_ulong "llx" +typedef int64_t xen_long_t; +#define PRI_xen_long "llx" +/* Guest handles for primitive C types. */ +__DEFINE_GUEST_HANDLE(uchar, unsigned char); +__DEFINE_GUEST_HANDLE(uint, unsigned int); +DEFINE_GUEST_HANDLE(char); +DEFINE_GUEST_HANDLE(int); +DEFINE_GUEST_HANDLE(void); +DEFINE_GUEST_HANDLE(uint64_t); +DEFINE_GUEST_HANDLE(uint32_t); +DEFINE_GUEST_HANDLE(xen_pfn_t); +DEFINE_GUEST_HANDLE(xen_ulong_t); + +/* Maximum number of virtual CPUs in multi-processor guests. */ +#define MAX_VIRT_CPUS 1 + +struct arch_vcpu_info { }; +struct arch_shared_info { }; + +/* TODO: Move pvclock definitions some place arch independent */ +struct pvclock_vcpu_time_info { + u32 version; + u32 pad0; + u64 tsc_timestamp; + u64 system_time; + u32 tsc_to_system_mul; + s8 tsc_shift; + u8 flags; + u8 pad[2]; +} __attribute__((__packed__)); /* 32 bytes */ + +/* It is OK to have a 12 bytes struct with no padding because it is packed */ +struct pvclock_wall_clock { + u32 version; + u32 sec; + u32 nsec; + u32 sec_hi; +} __attribute__((__packed__)); +#endif + +#endif /* _ASM_ARM_XEN_INTERFACE_H */ -- cgit v1.3.1