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 --- tools/testing/vma/main.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 57 insertions(+) create mode 100644 tools/testing/vma/main.c (limited to 'tools/testing/vma/main.c') diff --git a/tools/testing/vma/main.c b/tools/testing/vma/main.c new file mode 100644 index 000000000..18338f5d2 --- /dev/null +++ b/tools/testing/vma/main.c @@ -0,0 +1,57 @@ +// SPDX-License-Identifier: GPL-2.0-or-later + +#include "shared.h" +/* + * Directly import the VMA implementation here. Our vma_internal.h wrapper + * provides userland-equivalent functionality for everything vma.c uses. + */ +#include "../../../mm/vma_init.c" +#include "../../../mm/vma_exec.c" +#include "../../../mm/vma.c" + +/* Tests are included directly so they can test static functions in mm/vma.c. */ +#include "tests/merge.c" +#include "tests/mmap.c" +#include "tests/vma.c" + +int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT; + +/* Helper functions which utilise static kernel functions. */ + +struct vm_area_struct *merge_existing(struct vma_merge_struct *vmg) +{ + struct vm_area_struct *vma; + + vma = vma_merge_existing_range(vmg); + if (vma) + vma_assert_attached(vma); + return vma; +} + +int attach_vma(struct mm_struct *mm, struct vm_area_struct *vma) +{ + int res; + + res = vma_link(mm, vma); + if (!res) + vma_assert_attached(vma); + return res; +} + +/* Main test running which invokes tests/ *.c runners. */ +int main(void) +{ + int num_tests = 0, num_fail = 0; + + maple_tree_init(); + vma_state_init(); + + run_merge_tests(&num_tests, &num_fail); + run_mmap_tests(&num_tests, &num_fail); + run_vma_tests(&num_tests, &num_fail); + + printf("%d tests run, %d passed, %d failed.\n", + num_tests, num_tests - num_fail, num_fail); + + return num_fail == 0 ? EXIT_SUCCESS : EXIT_FAILURE; +} -- cgit v1.3.1