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/riscv/mm/physaddr.c | 51 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 51 insertions(+) create mode 100644 arch/riscv/mm/physaddr.c (limited to 'arch/riscv/mm/physaddr.c') diff --git a/arch/riscv/mm/physaddr.c b/arch/riscv/mm/physaddr.c new file mode 100644 index 000000000..b1836e948 --- /dev/null +++ b/arch/riscv/mm/physaddr.c @@ -0,0 +1,51 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include +#include +#include +#include + +phys_addr_t __virt_to_phys(unsigned long x) +{ + /* + * Boundary checking against the kernel linear mapping space. + */ + WARN(!is_linear_mapping(x) && !is_kernel_mapping(x), + "virt_to_phys used for non-linear address: %p (%pS)\n", + (void *)x, (void *)x); + + return __va_to_pa_nodebug(x); +} +EXPORT_SYMBOL(__virt_to_phys); + +phys_addr_t __phys_addr_symbol(unsigned long x) +{ + unsigned long kernel_start = kernel_map.virt_addr; + unsigned long kernel_end = kernel_start + kernel_map.size; + + /* + * Boundary checking against the kernel image mapping. + * __pa_symbol should only be used on kernel symbol addresses. + */ + VIRTUAL_BUG_ON(x < kernel_start || x > kernel_end); + + return __va_to_pa_nodebug(x); +} +EXPORT_SYMBOL(__phys_addr_symbol); + +phys_addr_t linear_mapping_va_to_pa(unsigned long x) +{ + BUG_ON(!kernel_map.va_pa_offset); + + return ((unsigned long)(x) - kernel_map.va_pa_offset); +} +EXPORT_SYMBOL(linear_mapping_va_to_pa); + +void *linear_mapping_pa_to_va(unsigned long x) +{ + BUG_ON(!kernel_map.va_pa_offset); + + return ((void *)((unsigned long)(x) + kernel_map.va_pa_offset)); +} +EXPORT_SYMBOL(linear_mapping_pa_to_va); -- cgit v1.3.1