diff mbox series

[v7,bpf-next,4/5] selftests/bpf: Add tests for open-coded task_vma iter

Message ID 20231013204426.1074286-5-davemarchevsky@fb.com (mailing list archive)
State Accepted
Commit e0e1a7a5fc377d54bd792c6368a375d41fc316ef
Delegated to: BPF
Headers show
Series Open-coded task_vma iter | expand

Checks

Context Check Description
bpf/vmtest-bpf-next-VM_Test-0 success Logs for ShellCheck
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for bpf-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 9 this patch: 9
netdev/cc_maintainers warning 11 maintainers not CCed: song@kernel.org mykolal@fb.com yonghong.song@linux.dev jolsa@kernel.org kpsingh@kernel.org john.fastabend@gmail.com shuah@kernel.org linux-kselftest@vger.kernel.org sdf@google.com haoluo@google.com martin.lau@linux.dev
netdev/build_clang success Errors and warnings before: 9 this patch: 9
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 9 this patch: 9
netdev/checkpatch warning CHECK: extern prototypes should be avoided in .h files WARNING: added, moved or deleted file(s), does MAINTAINERS need updating? WARNING: line length of 90 exceeds 80 columns
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
bpf/vmtest-bpf-next-PR success PR summary
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bpf/vmtest-bpf-next-VM_Test-1 success Logs for build for aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-9 success Logs for test_maps on x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-7 success Logs for test_maps on s390x with gcc
bpf/vmtest-bpf-next-VM_Test-10 success Logs for test_progs on aarch64 with gcc
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bpf/vmtest-bpf-next-VM_Test-11 success Logs for test_progs on s390x with gcc
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bpf/vmtest-bpf-next-VM_Test-23 success Logs for test_progs_parallel on x86_64 with llvm-16
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Commit Message

Dave Marchevsky Oct. 13, 2023, 8:44 p.m. UTC
The open-coded task_vma iter added earlier in this series allows for
natural iteration over a task's vmas using existing open-coded iter
infrastructure, specifically bpf_for_each.

This patch adds a test demonstrating this pattern and validating
correctness. The vma->vm_start and vma->vm_end addresses of the first
1000 vmas are recorded and compared to /proc/PID/maps output. As
expected, both see the same vmas and addresses - with the exception of
the [vsyscall] vma - which is explained in a comment in the prog_tests
program.

Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
---
 .../testing/selftests/bpf/bpf_experimental.h  |  8 +++
 .../testing/selftests/bpf/prog_tests/iters.c  | 58 +++++++++++++++++++
 .../selftests/bpf/progs/iters_task_vma.c      | 43 ++++++++++++++
 3 files changed, 109 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/progs/iters_task_vma.c
diff mbox series

Patch

diff --git a/tools/testing/selftests/bpf/bpf_experimental.h b/tools/testing/selftests/bpf/bpf_experimental.h
index 9aa29564bd74..2c8cb3f61529 100644
--- a/tools/testing/selftests/bpf/bpf_experimental.h
+++ b/tools/testing/selftests/bpf/bpf_experimental.h
@@ -159,6 +159,14 @@  extern void *bpf_percpu_obj_new_impl(__u64 local_type_id, void *meta) __ksym;
  */
 extern void bpf_percpu_obj_drop_impl(void *kptr, void *meta) __ksym;
 
+struct bpf_iter_task_vma;
+
+extern int bpf_iter_task_vma_new(struct bpf_iter_task_vma *it,
+				 struct task_struct *task,
+				 unsigned long addr) __ksym;
+extern struct vm_area_struct *bpf_iter_task_vma_next(struct bpf_iter_task_vma *it) __ksym;
+extern void bpf_iter_task_vma_destroy(struct bpf_iter_task_vma *it) __ksym;
+
 /* Convenience macro to wrap over bpf_obj_drop_impl */
 #define bpf_percpu_obj_drop(kptr) bpf_percpu_obj_drop_impl(kptr, NULL)
 
diff --git a/tools/testing/selftests/bpf/prog_tests/iters.c b/tools/testing/selftests/bpf/prog_tests/iters.c
index 10804ae5ae97..b696873c5455 100644
--- a/tools/testing/selftests/bpf/prog_tests/iters.c
+++ b/tools/testing/selftests/bpf/prog_tests/iters.c
@@ -8,6 +8,7 @@ 
 #include "iters_looping.skel.h"
 #include "iters_num.skel.h"
 #include "iters_testmod_seq.skel.h"
+#include "iters_task_vma.skel.h"
 
 static void subtest_num_iters(void)
 {
@@ -90,6 +91,61 @@  static void subtest_testmod_seq_iters(void)
 	iters_testmod_seq__destroy(skel);
 }
 
+static void subtest_task_vma_iters(void)
+{
+	unsigned long start, end, bpf_iter_start, bpf_iter_end;
+	struct iters_task_vma *skel;
+	char rest_of_line[1000];
+	unsigned int seen;
+	FILE *f = NULL;
+	int err;
+
+	skel = iters_task_vma__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "skel_open_and_load"))
+		return;
+
+	skel->bss->target_pid = getpid();
+
+	err = iters_task_vma__attach(skel);
+	if (!ASSERT_OK(err, "skel_attach"))
+		goto cleanup;
+
+	getpgid(skel->bss->target_pid);
+	iters_task_vma__detach(skel);
+
+	if (!ASSERT_GT(skel->bss->vmas_seen, 0, "vmas_seen_gt_zero"))
+		goto cleanup;
+
+	f = fopen("/proc/self/maps", "r");
+	if (!ASSERT_OK_PTR(f, "proc_maps_fopen"))
+		goto cleanup;
+
+	seen = 0;
+	while (fscanf(f, "%lx-%lx %[^\n]\n", &start, &end, rest_of_line) == 3) {
+		/* [vsyscall] vma isn't _really_ part of task->mm vmas.
+		 * /proc/PID/maps returns it when out of vmas - see get_gate_vma
+		 * calls in fs/proc/task_mmu.c
+		 */
+		if (strstr(rest_of_line, "[vsyscall]"))
+			continue;
+
+		bpf_iter_start = skel->bss->vm_ranges[seen].vm_start;
+		bpf_iter_end = skel->bss->vm_ranges[seen].vm_end;
+
+		ASSERT_EQ(bpf_iter_start, start, "vma->vm_start match");
+		ASSERT_EQ(bpf_iter_end, end, "vma->vm_end match");
+		seen++;
+	}
+
+	if (!ASSERT_EQ(skel->bss->vmas_seen, seen, "vmas_seen_eq"))
+		goto cleanup;
+
+cleanup:
+	if (f)
+		fclose(f);
+	iters_task_vma__destroy(skel);
+}
+
 void test_iters(void)
 {
 	RUN_TESTS(iters_state_safety);
@@ -103,4 +159,6 @@  void test_iters(void)
 		subtest_num_iters();
 	if (test__start_subtest("testmod_seq"))
 		subtest_testmod_seq_iters();
+	if (test__start_subtest("task_vma"))
+		subtest_task_vma_iters();
 }
diff --git a/tools/testing/selftests/bpf/progs/iters_task_vma.c b/tools/testing/selftests/bpf/progs/iters_task_vma.c
new file mode 100644
index 000000000000..44edecfdfaee
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/iters_task_vma.c
@@ -0,0 +1,43 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
+
+#include "vmlinux.h"
+#include "bpf_experimental.h"
+#include <bpf/bpf_helpers.h>
+#include "bpf_misc.h"
+
+pid_t target_pid = 0;
+unsigned int vmas_seen = 0;
+
+struct {
+	__u64 vm_start;
+	__u64 vm_end;
+} vm_ranges[1000];
+
+SEC("raw_tp/sys_enter")
+int iter_task_vma_for_each(const void *ctx)
+{
+	struct task_struct *task = bpf_get_current_task_btf();
+	struct vm_area_struct *vma;
+	unsigned int seen = 0;
+
+	if (task->pid != target_pid)
+		return 0;
+
+	if (vmas_seen)
+		return 0;
+
+	bpf_for_each(task_vma, vma, task, 0) {
+		if (seen >= 1000)
+			break;
+
+		vm_ranges[seen].vm_start = vma->vm_start;
+		vm_ranges[seen].vm_end = vma->vm_end;
+		seen++;
+	}
+
+	vmas_seen = seen;
+	return 0;
+}
+
+char _license[] SEC("license") = "GPL";