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/asm-generic/vdso/clocksource.h | 0 include/asm-generic/vdso/vsyscall.h | 35 ++++++++++++++++++++++++++++++++++ 2 files changed, 35 insertions(+) create mode 100644 include/asm-generic/vdso/clocksource.h create mode 100644 include/asm-generic/vdso/vsyscall.h (limited to 'include/asm-generic/vdso') diff --git a/include/asm-generic/vdso/clocksource.h b/include/asm-generic/vdso/clocksource.h new file mode 100644 index 000000000..e69de29bb diff --git a/include/asm-generic/vdso/vsyscall.h b/include/asm-generic/vdso/vsyscall.h new file mode 100644 index 000000000..a6b03cfba --- /dev/null +++ b/include/asm-generic/vdso/vsyscall.h @@ -0,0 +1,35 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_GENERIC_VSYSCALL_H +#define __ASM_GENERIC_VSYSCALL_H + +#ifndef __ASSEMBLER__ + +#ifndef __arch_get_vdso_u_time_data +static __always_inline const struct vdso_time_data *__arch_get_vdso_u_time_data(void) +{ + return &vdso_u_time_data; +} +#endif + +#ifndef __arch_get_vdso_u_rng_data +static __always_inline const struct vdso_rng_data *__arch_get_vdso_u_rng_data(void) +{ + return &vdso_u_rng_data; +} +#endif + +#ifndef __arch_update_vdso_clock +static __always_inline void __arch_update_vdso_clock(struct vdso_clock *vc) +{ +} +#endif /* __arch_update_vdso_clock */ + +#ifndef __arch_sync_vdso_time_data +static __always_inline void __arch_sync_vdso_time_data(struct vdso_time_data *vdata) +{ +} +#endif /* __arch_sync_vdso_time_data */ + +#endif /* !__ASSEMBLER__ */ + +#endif /* __ASM_GENERIC_VSYSCALL_H */ -- cgit v1.3.1