From: Chuyi Zhou <zhouchuyi@bytedance.com>
To: bpf@vger.kernel.org
Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org,
martin.lau@kernel.org, tj@kernel.org,
linux-kernel@vger.kernel.org,
Chuyi Zhou <zhouchuyi@bytedance.com>
Subject: [PATCH bpf-next v4 3/8] bpf: Introduce task open coded iterator kfuncs
Date: Sat, 7 Oct 2023 20:45:17 +0800 [thread overview]
Message-ID: <20231007124522.34834-4-zhouchuyi@bytedance.com> (raw)
In-Reply-To: <20231007124522.34834-1-zhouchuyi@bytedance.com>
This patch adds kfuncs bpf_iter_task_{new,next,destroy} which allow
creation and manipulation of struct bpf_iter_task in open-coded iterator
style. BPF programs can use these kfuncs or through bpf_for_each macro to
iterate all processes in the system.
The API design keep consistent with SEC("iter/task"). bpf_iter_task_new()
accepts a specific task and iterating type which allows:
1. iterating all process in the system(BPF_TASK_ITER_ALL_PROCS)
2. iterating all threads in the system(BPF_TASK_ITER_ALL_THREADS)
3. iterating all threads of a specific task(BPF_TASK_ITER_PROC_THREADS)
Signed-off-by: Chuyi Zhou <zhouchuyi@bytedance.com>
---
kernel/bpf/helpers.c | 3 +
kernel/bpf/task_iter.c | 82 +++++++++++++++++++
.../testing/selftests/bpf/bpf_experimental.h | 5 ++
3 files changed, 90 insertions(+)
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index 8699cabb52b2..8111437a999e 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -2552,6 +2552,9 @@ BTF_ID_FLAGS(func, bpf_iter_num_destroy, KF_ITER_DESTROY)
BTF_ID_FLAGS(func, bpf_iter_css_task_new, KF_ITER_NEW | KF_TRUSTED_ARGS)
BTF_ID_FLAGS(func, bpf_iter_css_task_next, KF_ITER_NEXT | KF_RET_NULL)
BTF_ID_FLAGS(func, bpf_iter_css_task_destroy, KF_ITER_DESTROY)
+BTF_ID_FLAGS(func, bpf_iter_task_new, KF_ITER_NEW | KF_TRUSTED_ARGS)
+BTF_ID_FLAGS(func, bpf_iter_task_next, KF_ITER_NEXT | KF_RET_NULL)
+BTF_ID_FLAGS(func, bpf_iter_task_destroy, KF_ITER_DESTROY)
BTF_ID_FLAGS(func, bpf_dynptr_adjust)
BTF_ID_FLAGS(func, bpf_dynptr_is_null)
BTF_ID_FLAGS(func, bpf_dynptr_is_rdonly)
diff --git a/kernel/bpf/task_iter.c b/kernel/bpf/task_iter.c
index 2cfcb4dd8a37..c2e1c3cbffea 100644
--- a/kernel/bpf/task_iter.c
+++ b/kernel/bpf/task_iter.c
@@ -856,6 +856,88 @@ __bpf_kfunc void bpf_iter_css_task_destroy(struct bpf_iter_css_task *it)
bpf_mem_free(&bpf_global_ma, kit->css_it);
}
+struct bpf_iter_task {
+ __u64 __opaque[3];
+} __attribute__((aligned(8)));
+
+struct bpf_iter_task_kern {
+ struct task_struct *task;
+ struct task_struct *pos;
+ unsigned int flags;
+} __attribute__((aligned(8)));
+
+enum {
+ BPF_TASK_ITER_ALL_PROCS,
+ BPF_TASK_ITER_ALL_THREADS,
+ BPF_TASK_ITER_PROC_THREADS
+};
+
+__bpf_kfunc int bpf_iter_task_new(struct bpf_iter_task *it,
+ struct task_struct *task, unsigned int flags)
+{
+ struct bpf_iter_task_kern *kit = (void *)it;
+
+ BUILD_BUG_ON(sizeof(struct bpf_iter_task_kern) != sizeof(struct bpf_iter_task));
+ BUILD_BUG_ON(__alignof__(struct bpf_iter_task_kern) !=
+ __alignof__(struct bpf_iter_task));
+
+ kit->task = kit->pos = NULL;
+ switch (flags) {
+ case BPF_TASK_ITER_ALL_THREADS:
+ case BPF_TASK_ITER_ALL_PROCS:
+ case BPF_TASK_ITER_PROC_THREADS:
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ if (flags == BPF_TASK_ITER_PROC_THREADS)
+ kit->task = task;
+ else
+ kit->task = &init_task;
+ kit->pos = kit->task;
+ kit->flags = flags;
+ return 0;
+}
+
+__bpf_kfunc struct task_struct *bpf_iter_task_next(struct bpf_iter_task *it)
+{
+ struct bpf_iter_task_kern *kit = (void *)it;
+ struct task_struct *pos;
+ unsigned int flags;
+
+ flags = kit->flags;
+ pos = kit->pos;
+
+ if (!pos)
+ goto out;
+
+ if (flags == BPF_TASK_ITER_ALL_PROCS)
+ goto get_next_task;
+
+ kit->pos = next_thread(kit->pos);
+ if (kit->pos == kit->task) {
+ if (flags == BPF_TASK_ITER_PROC_THREADS) {
+ kit->pos = NULL;
+ goto out;
+ }
+ } else
+ goto out;
+
+get_next_task:
+ kit->pos = next_task(kit->pos);
+ kit->task = kit->pos;
+ if (kit->pos == &init_task)
+ kit->pos = NULL;
+
+out:
+ return pos;
+}
+
+__bpf_kfunc void bpf_iter_task_destroy(struct bpf_iter_task *it)
+{
+}
+
DEFINE_PER_CPU(struct mmap_unlock_irq_work, mmap_unlock_work);
static void do_mmap_read_unlock(struct irq_work *entry)
diff --git a/tools/testing/selftests/bpf/bpf_experimental.h b/tools/testing/selftests/bpf/bpf_experimental.h
index 8b53537e0f27..1ec82997cce7 100644
--- a/tools/testing/selftests/bpf/bpf_experimental.h
+++ b/tools/testing/selftests/bpf/bpf_experimental.h
@@ -457,5 +457,10 @@ extern int bpf_iter_css_task_new(struct bpf_iter_css_task *it,
extern struct task_struct *bpf_iter_css_task_next(struct bpf_iter_css_task *it) __weak __ksym;
extern void bpf_iter_css_task_destroy(struct bpf_iter_css_task *it) __weak __ksym;
+struct bpf_iter_task;
+extern int bpf_iter_task_new(struct bpf_iter_task *it,
+ struct task_struct *task, unsigned int flags) __weak __ksym;
+extern struct task_struct *bpf_iter_task_next(struct bpf_iter_task *it) __weak __ksym;
+extern void bpf_iter_task_destroy(struct bpf_iter_task *it) __weak __ksym;
#endif
--
2.20.1
next prev parent reply other threads:[~2023-10-07 12:45 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-07 12:45 [PATCH bpf-next v4 0/8] Add Open-coded task, css_task and css iters Chuyi Zhou
2023-10-07 12:45 ` [PATCH bpf-next v4 1/8] cgroup: Prepare for using css_task_iter_*() in BPF Chuyi Zhou
2023-10-07 12:45 ` [PATCH bpf-next v4 2/8] bpf: Introduce css_task open-coded iterator kfuncs Chuyi Zhou
2023-10-07 14:40 ` kernel test robot
2023-10-07 12:45 ` Chuyi Zhou [this message]
2023-10-07 15:22 ` [PATCH bpf-next v4 3/8] bpf: Introduce task open coded " kernel test robot
2023-10-07 12:45 ` [PATCH bpf-next v4 4/8] bpf: Introduce css open-coded " Chuyi Zhou
2023-10-07 16:05 ` kernel test robot
2023-10-11 4:44 ` Chuyi Zhou
2023-10-11 5:32 ` Chuyi Zhou
2023-10-07 12:45 ` [PATCH bpf-next v4 5/8] bpf: teach the verifier to enforce css_iter and task_iter in RCU CS Chuyi Zhou
2023-10-07 12:45 ` [PATCH bpf-next v4 6/8] bpf: Let bpf_iter_task_new accept null task ptr Chuyi Zhou
2023-10-07 12:45 ` [PATCH bpf-next v4 7/8] selftests/bpf: rename bpf_iter_task.c to bpf_iter_tasks.c Chuyi Zhou
2023-10-07 12:45 ` [PATCH bpf-next v4 8/8] selftests/bpf: Add tests for open-coded task and css iter Chuyi Zhou
2023-10-10 8:01 ` [PATCH bpf-next v4 0/8] Add Open-coded task, css_task and css iters Daniel Borkmann
2023-10-10 8:14 ` Chuyi Zhou
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