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https://gitee.com/bianbu-linux/linux-6.6
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f85671c6ef
In commit 22df776a9a ("tasks: Extract rcu_users out of union"), the
'refcount_t rcu_users' field was extracted out of a union with the
'struct rcu_head rcu' field. This allows us to safely perform a
refcount_inc_not_zero() on task->rcu_users when acquiring a reference on
a task struct. A prior patch leveraged this by making struct task_struct
an RCU-protected object in the verifier, and by bpf_task_acquire() to
use the task->rcu_users field for synchronization.
Now that we can use RCU to protect tasks, we no longer need
bpf_task_kptr_get(), or bpf_task_acquire_not_zero(). bpf_task_kptr_get()
is truly completely unnecessary, as we can just use RCU to get the
object. bpf_task_acquire_not_zero() is now equivalent to
bpf_task_acquire().
In addition to these changes, this patch also updates the associated
selftests to no longer use these kfuncs.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230331195733.699708-3-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
96 lines
2.1 KiB
C
96 lines
2.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
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#define _GNU_SOURCE
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#include <sys/wait.h>
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#include <test_progs.h>
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#include <unistd.h>
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#include "task_kfunc_failure.skel.h"
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#include "task_kfunc_success.skel.h"
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static struct task_kfunc_success *open_load_task_kfunc_skel(void)
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{
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struct task_kfunc_success *skel;
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int err;
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skel = task_kfunc_success__open();
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if (!ASSERT_OK_PTR(skel, "skel_open"))
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return NULL;
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skel->bss->pid = getpid();
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err = task_kfunc_success__load(skel);
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if (!ASSERT_OK(err, "skel_load"))
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goto cleanup;
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return skel;
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cleanup:
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task_kfunc_success__destroy(skel);
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return NULL;
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}
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static void run_success_test(const char *prog_name)
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{
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struct task_kfunc_success *skel;
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int status;
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pid_t child_pid;
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struct bpf_program *prog;
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struct bpf_link *link = NULL;
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skel = open_load_task_kfunc_skel();
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if (!ASSERT_OK_PTR(skel, "open_load_skel"))
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return;
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if (!ASSERT_OK(skel->bss->err, "pre_spawn_err"))
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goto cleanup;
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prog = bpf_object__find_program_by_name(skel->obj, prog_name);
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if (!ASSERT_OK_PTR(prog, "bpf_object__find_program_by_name"))
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goto cleanup;
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link = bpf_program__attach(prog);
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if (!ASSERT_OK_PTR(link, "attached_link"))
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goto cleanup;
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child_pid = fork();
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if (!ASSERT_GT(child_pid, -1, "child_pid"))
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goto cleanup;
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if (child_pid == 0)
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_exit(0);
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waitpid(child_pid, &status, 0);
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ASSERT_OK(skel->bss->err, "post_wait_err");
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cleanup:
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bpf_link__destroy(link);
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task_kfunc_success__destroy(skel);
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}
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static const char * const success_tests[] = {
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"test_task_acquire_release_argument",
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"test_task_acquire_release_current",
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"test_task_acquire_leave_in_map",
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"test_task_xchg_release",
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"test_task_map_acquire_release",
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"test_task_current_acquire_release",
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"test_task_from_pid_arg",
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"test_task_from_pid_current",
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"test_task_from_pid_invalid",
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"task_kfunc_acquire_trusted_walked",
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};
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void test_task_kfunc(void)
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{
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int i;
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for (i = 0; i < ARRAY_SIZE(success_tests); i++) {
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if (!test__start_subtest(success_tests[i]))
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continue;
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run_success_test(success_tests[i]);
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}
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RUN_TESTS(task_kfunc_failure);
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}
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