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bc239eb271
After commit 0ede61d858
("file: convert to SLAB_TYPESAFE_BY_RCU") this
loop always iterates exactly one time. Delete the for statement and pull
the code in a tab.
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/bpf/ZoWJF51D4zWb6f5t@stanley.mountain
1075 lines
26 KiB
C
1075 lines
26 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/* Copyright (c) 2020 Facebook */
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#include <linux/init.h>
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#include <linux/namei.h>
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#include <linux/pid_namespace.h>
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#include <linux/fs.h>
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#include <linux/fdtable.h>
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#include <linux/filter.h>
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#include <linux/bpf_mem_alloc.h>
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#include <linux/btf_ids.h>
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#include <linux/mm_types.h>
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#include "mmap_unlock_work.h"
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static const char * const iter_task_type_names[] = {
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"ALL",
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"TID",
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"PID",
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};
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struct bpf_iter_seq_task_common {
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struct pid_namespace *ns;
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enum bpf_iter_task_type type;
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u32 pid;
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u32 pid_visiting;
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};
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struct bpf_iter_seq_task_info {
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/* The first field must be struct bpf_iter_seq_task_common.
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* this is assumed by {init, fini}_seq_pidns() callback functions.
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*/
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struct bpf_iter_seq_task_common common;
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u32 tid;
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};
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static struct task_struct *task_group_seq_get_next(struct bpf_iter_seq_task_common *common,
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u32 *tid,
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bool skip_if_dup_files)
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{
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struct task_struct *task;
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struct pid *pid;
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u32 next_tid;
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if (!*tid) {
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/* The first time, the iterator calls this function. */
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pid = find_pid_ns(common->pid, common->ns);
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task = get_pid_task(pid, PIDTYPE_TGID);
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if (!task)
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return NULL;
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*tid = common->pid;
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common->pid_visiting = common->pid;
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return task;
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}
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/* If the control returns to user space and comes back to the
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* kernel again, *tid and common->pid_visiting should be the
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* same for task_seq_start() to pick up the correct task.
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*/
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if (*tid == common->pid_visiting) {
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pid = find_pid_ns(common->pid_visiting, common->ns);
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task = get_pid_task(pid, PIDTYPE_PID);
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return task;
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}
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task = find_task_by_pid_ns(common->pid_visiting, common->ns);
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if (!task)
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return NULL;
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retry:
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task = __next_thread(task);
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if (!task)
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return NULL;
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next_tid = __task_pid_nr_ns(task, PIDTYPE_PID, common->ns);
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if (!next_tid)
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goto retry;
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if (skip_if_dup_files && task->files == task->group_leader->files)
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goto retry;
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*tid = common->pid_visiting = next_tid;
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get_task_struct(task);
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return task;
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}
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static struct task_struct *task_seq_get_next(struct bpf_iter_seq_task_common *common,
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u32 *tid,
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bool skip_if_dup_files)
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{
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struct task_struct *task = NULL;
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struct pid *pid;
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if (common->type == BPF_TASK_ITER_TID) {
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if (*tid && *tid != common->pid)
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return NULL;
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rcu_read_lock();
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pid = find_pid_ns(common->pid, common->ns);
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if (pid) {
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task = get_pid_task(pid, PIDTYPE_TGID);
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*tid = common->pid;
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}
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rcu_read_unlock();
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return task;
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}
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if (common->type == BPF_TASK_ITER_TGID) {
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rcu_read_lock();
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task = task_group_seq_get_next(common, tid, skip_if_dup_files);
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rcu_read_unlock();
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return task;
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}
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rcu_read_lock();
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retry:
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pid = find_ge_pid(*tid, common->ns);
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if (pid) {
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*tid = pid_nr_ns(pid, common->ns);
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task = get_pid_task(pid, PIDTYPE_PID);
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if (!task) {
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++*tid;
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goto retry;
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} else if (skip_if_dup_files && !thread_group_leader(task) &&
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task->files == task->group_leader->files) {
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put_task_struct(task);
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task = NULL;
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++*tid;
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goto retry;
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}
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}
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rcu_read_unlock();
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return task;
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}
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static void *task_seq_start(struct seq_file *seq, loff_t *pos)
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{
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struct bpf_iter_seq_task_info *info = seq->private;
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struct task_struct *task;
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task = task_seq_get_next(&info->common, &info->tid, false);
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if (!task)
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return NULL;
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if (*pos == 0)
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++*pos;
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return task;
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}
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static void *task_seq_next(struct seq_file *seq, void *v, loff_t *pos)
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{
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struct bpf_iter_seq_task_info *info = seq->private;
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struct task_struct *task;
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++*pos;
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++info->tid;
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put_task_struct((struct task_struct *)v);
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task = task_seq_get_next(&info->common, &info->tid, false);
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if (!task)
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return NULL;
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return task;
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}
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struct bpf_iter__task {
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__bpf_md_ptr(struct bpf_iter_meta *, meta);
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__bpf_md_ptr(struct task_struct *, task);
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};
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DEFINE_BPF_ITER_FUNC(task, struct bpf_iter_meta *meta, struct task_struct *task)
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static int __task_seq_show(struct seq_file *seq, struct task_struct *task,
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bool in_stop)
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{
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struct bpf_iter_meta meta;
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struct bpf_iter__task ctx;
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struct bpf_prog *prog;
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meta.seq = seq;
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prog = bpf_iter_get_info(&meta, in_stop);
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if (!prog)
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return 0;
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ctx.meta = &meta;
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ctx.task = task;
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return bpf_iter_run_prog(prog, &ctx);
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}
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static int task_seq_show(struct seq_file *seq, void *v)
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{
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return __task_seq_show(seq, v, false);
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}
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static void task_seq_stop(struct seq_file *seq, void *v)
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{
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if (!v)
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(void)__task_seq_show(seq, v, true);
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else
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put_task_struct((struct task_struct *)v);
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}
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static int bpf_iter_attach_task(struct bpf_prog *prog,
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union bpf_iter_link_info *linfo,
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struct bpf_iter_aux_info *aux)
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{
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unsigned int flags;
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struct pid *pid;
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pid_t tgid;
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if ((!!linfo->task.tid + !!linfo->task.pid + !!linfo->task.pid_fd) > 1)
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return -EINVAL;
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aux->task.type = BPF_TASK_ITER_ALL;
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if (linfo->task.tid != 0) {
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aux->task.type = BPF_TASK_ITER_TID;
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aux->task.pid = linfo->task.tid;
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}
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if (linfo->task.pid != 0) {
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aux->task.type = BPF_TASK_ITER_TGID;
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aux->task.pid = linfo->task.pid;
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}
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if (linfo->task.pid_fd != 0) {
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aux->task.type = BPF_TASK_ITER_TGID;
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pid = pidfd_get_pid(linfo->task.pid_fd, &flags);
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if (IS_ERR(pid))
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return PTR_ERR(pid);
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tgid = pid_nr_ns(pid, task_active_pid_ns(current));
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aux->task.pid = tgid;
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put_pid(pid);
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}
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return 0;
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}
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static const struct seq_operations task_seq_ops = {
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.start = task_seq_start,
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.next = task_seq_next,
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.stop = task_seq_stop,
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.show = task_seq_show,
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};
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struct bpf_iter_seq_task_file_info {
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/* The first field must be struct bpf_iter_seq_task_common.
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* this is assumed by {init, fini}_seq_pidns() callback functions.
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*/
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struct bpf_iter_seq_task_common common;
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struct task_struct *task;
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u32 tid;
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u32 fd;
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};
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static struct file *
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task_file_seq_get_next(struct bpf_iter_seq_task_file_info *info)
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{
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u32 saved_tid = info->tid;
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struct task_struct *curr_task;
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unsigned int curr_fd = info->fd;
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struct file *f;
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/* If this function returns a non-NULL file object,
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* it held a reference to the task/file.
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* Otherwise, it does not hold any reference.
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*/
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again:
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if (info->task) {
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curr_task = info->task;
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curr_fd = info->fd;
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} else {
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curr_task = task_seq_get_next(&info->common, &info->tid, true);
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if (!curr_task) {
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info->task = NULL;
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return NULL;
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}
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/* set info->task */
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info->task = curr_task;
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if (saved_tid == info->tid)
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curr_fd = info->fd;
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else
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curr_fd = 0;
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}
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rcu_read_lock();
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f = task_lookup_next_fdget_rcu(curr_task, &curr_fd);
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if (f) {
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/* set info->fd */
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info->fd = curr_fd;
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rcu_read_unlock();
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return f;
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}
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/* the current task is done, go to the next task */
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rcu_read_unlock();
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put_task_struct(curr_task);
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if (info->common.type == BPF_TASK_ITER_TID) {
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info->task = NULL;
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return NULL;
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}
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info->task = NULL;
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info->fd = 0;
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saved_tid = ++(info->tid);
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goto again;
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}
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static void *task_file_seq_start(struct seq_file *seq, loff_t *pos)
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{
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struct bpf_iter_seq_task_file_info *info = seq->private;
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struct file *file;
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info->task = NULL;
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file = task_file_seq_get_next(info);
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if (file && *pos == 0)
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++*pos;
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return file;
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}
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static void *task_file_seq_next(struct seq_file *seq, void *v, loff_t *pos)
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{
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struct bpf_iter_seq_task_file_info *info = seq->private;
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++*pos;
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++info->fd;
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fput((struct file *)v);
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return task_file_seq_get_next(info);
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}
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struct bpf_iter__task_file {
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__bpf_md_ptr(struct bpf_iter_meta *, meta);
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__bpf_md_ptr(struct task_struct *, task);
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u32 fd __aligned(8);
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__bpf_md_ptr(struct file *, file);
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};
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DEFINE_BPF_ITER_FUNC(task_file, struct bpf_iter_meta *meta,
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struct task_struct *task, u32 fd,
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struct file *file)
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static int __task_file_seq_show(struct seq_file *seq, struct file *file,
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bool in_stop)
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{
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struct bpf_iter_seq_task_file_info *info = seq->private;
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struct bpf_iter__task_file ctx;
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struct bpf_iter_meta meta;
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struct bpf_prog *prog;
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meta.seq = seq;
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prog = bpf_iter_get_info(&meta, in_stop);
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if (!prog)
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return 0;
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ctx.meta = &meta;
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ctx.task = info->task;
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ctx.fd = info->fd;
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ctx.file = file;
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return bpf_iter_run_prog(prog, &ctx);
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}
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static int task_file_seq_show(struct seq_file *seq, void *v)
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{
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return __task_file_seq_show(seq, v, false);
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}
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static void task_file_seq_stop(struct seq_file *seq, void *v)
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{
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struct bpf_iter_seq_task_file_info *info = seq->private;
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if (!v) {
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(void)__task_file_seq_show(seq, v, true);
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} else {
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fput((struct file *)v);
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put_task_struct(info->task);
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info->task = NULL;
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}
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}
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static int init_seq_pidns(void *priv_data, struct bpf_iter_aux_info *aux)
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{
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struct bpf_iter_seq_task_common *common = priv_data;
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common->ns = get_pid_ns(task_active_pid_ns(current));
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common->type = aux->task.type;
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common->pid = aux->task.pid;
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return 0;
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}
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static void fini_seq_pidns(void *priv_data)
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{
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struct bpf_iter_seq_task_common *common = priv_data;
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put_pid_ns(common->ns);
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}
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static const struct seq_operations task_file_seq_ops = {
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.start = task_file_seq_start,
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.next = task_file_seq_next,
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.stop = task_file_seq_stop,
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.show = task_file_seq_show,
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};
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struct bpf_iter_seq_task_vma_info {
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/* The first field must be struct bpf_iter_seq_task_common.
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* this is assumed by {init, fini}_seq_pidns() callback functions.
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*/
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struct bpf_iter_seq_task_common common;
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struct task_struct *task;
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struct mm_struct *mm;
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struct vm_area_struct *vma;
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u32 tid;
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unsigned long prev_vm_start;
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unsigned long prev_vm_end;
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};
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enum bpf_task_vma_iter_find_op {
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task_vma_iter_first_vma, /* use find_vma() with addr 0 */
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task_vma_iter_next_vma, /* use vma_next() with curr_vma */
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task_vma_iter_find_vma, /* use find_vma() to find next vma */
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};
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static struct vm_area_struct *
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task_vma_seq_get_next(struct bpf_iter_seq_task_vma_info *info)
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{
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enum bpf_task_vma_iter_find_op op;
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struct vm_area_struct *curr_vma;
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struct task_struct *curr_task;
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struct mm_struct *curr_mm;
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u32 saved_tid = info->tid;
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/* If this function returns a non-NULL vma, it holds a reference to
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* the task_struct, holds a refcount on mm->mm_users, and holds
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* read lock on vma->mm->mmap_lock.
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* If this function returns NULL, it does not hold any reference or
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* lock.
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*/
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if (info->task) {
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curr_task = info->task;
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curr_vma = info->vma;
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curr_mm = info->mm;
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/* In case of lock contention, drop mmap_lock to unblock
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* the writer.
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*
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* After relock, call find(mm, prev_vm_end - 1) to find
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* new vma to process.
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*
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* +------+------+-----------+
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* | VMA1 | VMA2 | VMA3 |
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* +------+------+-----------+
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* | | | |
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* 4k 8k 16k 400k
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*
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* For example, curr_vma == VMA2. Before unlock, we set
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*
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* prev_vm_start = 8k
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* prev_vm_end = 16k
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*
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* There are a few cases:
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*
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* 1) VMA2 is freed, but VMA3 exists.
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*
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* find_vma() will return VMA3, just process VMA3.
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*
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* 2) VMA2 still exists.
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*
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* find_vma() will return VMA2, process VMA2->next.
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*
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* 3) no more vma in this mm.
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*
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* Process the next task.
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*
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* 4) find_vma() returns a different vma, VMA2'.
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*
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* 4.1) If VMA2 covers same range as VMA2', skip VMA2',
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* because we already covered the range;
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* 4.2) VMA2 and VMA2' covers different ranges, process
|
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* VMA2'.
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*/
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if (mmap_lock_is_contended(curr_mm)) {
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info->prev_vm_start = curr_vma->vm_start;
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info->prev_vm_end = curr_vma->vm_end;
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op = task_vma_iter_find_vma;
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mmap_read_unlock(curr_mm);
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|
if (mmap_read_lock_killable(curr_mm)) {
|
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mmput(curr_mm);
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goto finish;
|
|
}
|
|
} else {
|
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op = task_vma_iter_next_vma;
|
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}
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} else {
|
|
again:
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curr_task = task_seq_get_next(&info->common, &info->tid, true);
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|
if (!curr_task) {
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info->tid++;
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goto finish;
|
|
}
|
|
|
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if (saved_tid != info->tid) {
|
|
/* new task, process the first vma */
|
|
op = task_vma_iter_first_vma;
|
|
} else {
|
|
/* Found the same tid, which means the user space
|
|
* finished data in previous buffer and read more.
|
|
* We dropped mmap_lock before returning to user
|
|
* space, so it is necessary to use find_vma() to
|
|
* find the next vma to process.
|
|
*/
|
|
op = task_vma_iter_find_vma;
|
|
}
|
|
|
|
curr_mm = get_task_mm(curr_task);
|
|
if (!curr_mm)
|
|
goto next_task;
|
|
|
|
if (mmap_read_lock_killable(curr_mm)) {
|
|
mmput(curr_mm);
|
|
goto finish;
|
|
}
|
|
}
|
|
|
|
switch (op) {
|
|
case task_vma_iter_first_vma:
|
|
curr_vma = find_vma(curr_mm, 0);
|
|
break;
|
|
case task_vma_iter_next_vma:
|
|
curr_vma = find_vma(curr_mm, curr_vma->vm_end);
|
|
break;
|
|
case task_vma_iter_find_vma:
|
|
/* We dropped mmap_lock so it is necessary to use find_vma
|
|
* to find the next vma. This is similar to the mechanism
|
|
* in show_smaps_rollup().
|
|
*/
|
|
curr_vma = find_vma(curr_mm, info->prev_vm_end - 1);
|
|
/* case 1) and 4.2) above just use curr_vma */
|
|
|
|
/* check for case 2) or case 4.1) above */
|
|
if (curr_vma &&
|
|
curr_vma->vm_start == info->prev_vm_start &&
|
|
curr_vma->vm_end == info->prev_vm_end)
|
|
curr_vma = find_vma(curr_mm, curr_vma->vm_end);
|
|
break;
|
|
}
|
|
if (!curr_vma) {
|
|
/* case 3) above, or case 2) 4.1) with vma->next == NULL */
|
|
mmap_read_unlock(curr_mm);
|
|
mmput(curr_mm);
|
|
goto next_task;
|
|
}
|
|
info->task = curr_task;
|
|
info->vma = curr_vma;
|
|
info->mm = curr_mm;
|
|
return curr_vma;
|
|
|
|
next_task:
|
|
if (info->common.type == BPF_TASK_ITER_TID)
|
|
goto finish;
|
|
|
|
put_task_struct(curr_task);
|
|
info->task = NULL;
|
|
info->mm = NULL;
|
|
info->tid++;
|
|
goto again;
|
|
|
|
finish:
|
|
if (curr_task)
|
|
put_task_struct(curr_task);
|
|
info->task = NULL;
|
|
info->vma = NULL;
|
|
info->mm = NULL;
|
|
return NULL;
|
|
}
|
|
|
|
static void *task_vma_seq_start(struct seq_file *seq, loff_t *pos)
|
|
{
|
|
struct bpf_iter_seq_task_vma_info *info = seq->private;
|
|
struct vm_area_struct *vma;
|
|
|
|
vma = task_vma_seq_get_next(info);
|
|
if (vma && *pos == 0)
|
|
++*pos;
|
|
|
|
return vma;
|
|
}
|
|
|
|
static void *task_vma_seq_next(struct seq_file *seq, void *v, loff_t *pos)
|
|
{
|
|
struct bpf_iter_seq_task_vma_info *info = seq->private;
|
|
|
|
++*pos;
|
|
return task_vma_seq_get_next(info);
|
|
}
|
|
|
|
struct bpf_iter__task_vma {
|
|
__bpf_md_ptr(struct bpf_iter_meta *, meta);
|
|
__bpf_md_ptr(struct task_struct *, task);
|
|
__bpf_md_ptr(struct vm_area_struct *, vma);
|
|
};
|
|
|
|
DEFINE_BPF_ITER_FUNC(task_vma, struct bpf_iter_meta *meta,
|
|
struct task_struct *task, struct vm_area_struct *vma)
|
|
|
|
static int __task_vma_seq_show(struct seq_file *seq, bool in_stop)
|
|
{
|
|
struct bpf_iter_seq_task_vma_info *info = seq->private;
|
|
struct bpf_iter__task_vma ctx;
|
|
struct bpf_iter_meta meta;
|
|
struct bpf_prog *prog;
|
|
|
|
meta.seq = seq;
|
|
prog = bpf_iter_get_info(&meta, in_stop);
|
|
if (!prog)
|
|
return 0;
|
|
|
|
ctx.meta = &meta;
|
|
ctx.task = info->task;
|
|
ctx.vma = info->vma;
|
|
return bpf_iter_run_prog(prog, &ctx);
|
|
}
|
|
|
|
static int task_vma_seq_show(struct seq_file *seq, void *v)
|
|
{
|
|
return __task_vma_seq_show(seq, false);
|
|
}
|
|
|
|
static void task_vma_seq_stop(struct seq_file *seq, void *v)
|
|
{
|
|
struct bpf_iter_seq_task_vma_info *info = seq->private;
|
|
|
|
if (!v) {
|
|
(void)__task_vma_seq_show(seq, true);
|
|
} else {
|
|
/* info->vma has not been seen by the BPF program. If the
|
|
* user space reads more, task_vma_seq_get_next should
|
|
* return this vma again. Set prev_vm_start to ~0UL,
|
|
* so that we don't skip the vma returned by the next
|
|
* find_vma() (case task_vma_iter_find_vma in
|
|
* task_vma_seq_get_next()).
|
|
*/
|
|
info->prev_vm_start = ~0UL;
|
|
info->prev_vm_end = info->vma->vm_end;
|
|
mmap_read_unlock(info->mm);
|
|
mmput(info->mm);
|
|
info->mm = NULL;
|
|
put_task_struct(info->task);
|
|
info->task = NULL;
|
|
}
|
|
}
|
|
|
|
static const struct seq_operations task_vma_seq_ops = {
|
|
.start = task_vma_seq_start,
|
|
.next = task_vma_seq_next,
|
|
.stop = task_vma_seq_stop,
|
|
.show = task_vma_seq_show,
|
|
};
|
|
|
|
static const struct bpf_iter_seq_info task_seq_info = {
|
|
.seq_ops = &task_seq_ops,
|
|
.init_seq_private = init_seq_pidns,
|
|
.fini_seq_private = fini_seq_pidns,
|
|
.seq_priv_size = sizeof(struct bpf_iter_seq_task_info),
|
|
};
|
|
|
|
static int bpf_iter_fill_link_info(const struct bpf_iter_aux_info *aux, struct bpf_link_info *info)
|
|
{
|
|
switch (aux->task.type) {
|
|
case BPF_TASK_ITER_TID:
|
|
info->iter.task.tid = aux->task.pid;
|
|
break;
|
|
case BPF_TASK_ITER_TGID:
|
|
info->iter.task.pid = aux->task.pid;
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static void bpf_iter_task_show_fdinfo(const struct bpf_iter_aux_info *aux, struct seq_file *seq)
|
|
{
|
|
seq_printf(seq, "task_type:\t%s\n", iter_task_type_names[aux->task.type]);
|
|
if (aux->task.type == BPF_TASK_ITER_TID)
|
|
seq_printf(seq, "tid:\t%u\n", aux->task.pid);
|
|
else if (aux->task.type == BPF_TASK_ITER_TGID)
|
|
seq_printf(seq, "pid:\t%u\n", aux->task.pid);
|
|
}
|
|
|
|
static struct bpf_iter_reg task_reg_info = {
|
|
.target = "task",
|
|
.attach_target = bpf_iter_attach_task,
|
|
.feature = BPF_ITER_RESCHED,
|
|
.ctx_arg_info_size = 1,
|
|
.ctx_arg_info = {
|
|
{ offsetof(struct bpf_iter__task, task),
|
|
PTR_TO_BTF_ID_OR_NULL | PTR_TRUSTED },
|
|
},
|
|
.seq_info = &task_seq_info,
|
|
.fill_link_info = bpf_iter_fill_link_info,
|
|
.show_fdinfo = bpf_iter_task_show_fdinfo,
|
|
};
|
|
|
|
static const struct bpf_iter_seq_info task_file_seq_info = {
|
|
.seq_ops = &task_file_seq_ops,
|
|
.init_seq_private = init_seq_pidns,
|
|
.fini_seq_private = fini_seq_pidns,
|
|
.seq_priv_size = sizeof(struct bpf_iter_seq_task_file_info),
|
|
};
|
|
|
|
static struct bpf_iter_reg task_file_reg_info = {
|
|
.target = "task_file",
|
|
.attach_target = bpf_iter_attach_task,
|
|
.feature = BPF_ITER_RESCHED,
|
|
.ctx_arg_info_size = 2,
|
|
.ctx_arg_info = {
|
|
{ offsetof(struct bpf_iter__task_file, task),
|
|
PTR_TO_BTF_ID_OR_NULL },
|
|
{ offsetof(struct bpf_iter__task_file, file),
|
|
PTR_TO_BTF_ID_OR_NULL },
|
|
},
|
|
.seq_info = &task_file_seq_info,
|
|
.fill_link_info = bpf_iter_fill_link_info,
|
|
.show_fdinfo = bpf_iter_task_show_fdinfo,
|
|
};
|
|
|
|
static const struct bpf_iter_seq_info task_vma_seq_info = {
|
|
.seq_ops = &task_vma_seq_ops,
|
|
.init_seq_private = init_seq_pidns,
|
|
.fini_seq_private = fini_seq_pidns,
|
|
.seq_priv_size = sizeof(struct bpf_iter_seq_task_vma_info),
|
|
};
|
|
|
|
static struct bpf_iter_reg task_vma_reg_info = {
|
|
.target = "task_vma",
|
|
.attach_target = bpf_iter_attach_task,
|
|
.feature = BPF_ITER_RESCHED,
|
|
.ctx_arg_info_size = 2,
|
|
.ctx_arg_info = {
|
|
{ offsetof(struct bpf_iter__task_vma, task),
|
|
PTR_TO_BTF_ID_OR_NULL },
|
|
{ offsetof(struct bpf_iter__task_vma, vma),
|
|
PTR_TO_BTF_ID_OR_NULL },
|
|
},
|
|
.seq_info = &task_vma_seq_info,
|
|
.fill_link_info = bpf_iter_fill_link_info,
|
|
.show_fdinfo = bpf_iter_task_show_fdinfo,
|
|
};
|
|
|
|
BPF_CALL_5(bpf_find_vma, struct task_struct *, task, u64, start,
|
|
bpf_callback_t, callback_fn, void *, callback_ctx, u64, flags)
|
|
{
|
|
struct mmap_unlock_irq_work *work = NULL;
|
|
struct vm_area_struct *vma;
|
|
bool irq_work_busy = false;
|
|
struct mm_struct *mm;
|
|
int ret = -ENOENT;
|
|
|
|
if (flags)
|
|
return -EINVAL;
|
|
|
|
if (!task)
|
|
return -ENOENT;
|
|
|
|
mm = task->mm;
|
|
if (!mm)
|
|
return -ENOENT;
|
|
|
|
irq_work_busy = bpf_mmap_unlock_get_irq_work(&work);
|
|
|
|
if (irq_work_busy || !mmap_read_trylock(mm))
|
|
return -EBUSY;
|
|
|
|
vma = find_vma(mm, start);
|
|
|
|
if (vma && vma->vm_start <= start && vma->vm_end > start) {
|
|
callback_fn((u64)(long)task, (u64)(long)vma,
|
|
(u64)(long)callback_ctx, 0, 0);
|
|
ret = 0;
|
|
}
|
|
bpf_mmap_unlock_mm(work, mm);
|
|
return ret;
|
|
}
|
|
|
|
const struct bpf_func_proto bpf_find_vma_proto = {
|
|
.func = bpf_find_vma,
|
|
.ret_type = RET_INTEGER,
|
|
.arg1_type = ARG_PTR_TO_BTF_ID,
|
|
.arg1_btf_id = &btf_tracing_ids[BTF_TRACING_TYPE_TASK],
|
|
.arg2_type = ARG_ANYTHING,
|
|
.arg3_type = ARG_PTR_TO_FUNC,
|
|
.arg4_type = ARG_PTR_TO_STACK_OR_NULL,
|
|
.arg5_type = ARG_ANYTHING,
|
|
};
|
|
|
|
struct bpf_iter_task_vma_kern_data {
|
|
struct task_struct *task;
|
|
struct mm_struct *mm;
|
|
struct mmap_unlock_irq_work *work;
|
|
struct vma_iterator vmi;
|
|
};
|
|
|
|
struct bpf_iter_task_vma {
|
|
/* opaque iterator state; having __u64 here allows to preserve correct
|
|
* alignment requirements in vmlinux.h, generated from BTF
|
|
*/
|
|
__u64 __opaque[1];
|
|
} __attribute__((aligned(8)));
|
|
|
|
/* Non-opaque version of bpf_iter_task_vma */
|
|
struct bpf_iter_task_vma_kern {
|
|
struct bpf_iter_task_vma_kern_data *data;
|
|
} __attribute__((aligned(8)));
|
|
|
|
__bpf_kfunc_start_defs();
|
|
|
|
__bpf_kfunc int bpf_iter_task_vma_new(struct bpf_iter_task_vma *it,
|
|
struct task_struct *task, u64 addr)
|
|
{
|
|
struct bpf_iter_task_vma_kern *kit = (void *)it;
|
|
bool irq_work_busy = false;
|
|
int err;
|
|
|
|
BUILD_BUG_ON(sizeof(struct bpf_iter_task_vma_kern) != sizeof(struct bpf_iter_task_vma));
|
|
BUILD_BUG_ON(__alignof__(struct bpf_iter_task_vma_kern) != __alignof__(struct bpf_iter_task_vma));
|
|
|
|
/* is_iter_reg_valid_uninit guarantees that kit hasn't been initialized
|
|
* before, so non-NULL kit->data doesn't point to previously
|
|
* bpf_mem_alloc'd bpf_iter_task_vma_kern_data
|
|
*/
|
|
kit->data = bpf_mem_alloc(&bpf_global_ma, sizeof(struct bpf_iter_task_vma_kern_data));
|
|
if (!kit->data)
|
|
return -ENOMEM;
|
|
|
|
kit->data->task = get_task_struct(task);
|
|
kit->data->mm = task->mm;
|
|
if (!kit->data->mm) {
|
|
err = -ENOENT;
|
|
goto err_cleanup_iter;
|
|
}
|
|
|
|
/* kit->data->work == NULL is valid after bpf_mmap_unlock_get_irq_work */
|
|
irq_work_busy = bpf_mmap_unlock_get_irq_work(&kit->data->work);
|
|
if (irq_work_busy || !mmap_read_trylock(kit->data->mm)) {
|
|
err = -EBUSY;
|
|
goto err_cleanup_iter;
|
|
}
|
|
|
|
vma_iter_init(&kit->data->vmi, kit->data->mm, addr);
|
|
return 0;
|
|
|
|
err_cleanup_iter:
|
|
if (kit->data->task)
|
|
put_task_struct(kit->data->task);
|
|
bpf_mem_free(&bpf_global_ma, kit->data);
|
|
/* NULL kit->data signals failed bpf_iter_task_vma initialization */
|
|
kit->data = NULL;
|
|
return err;
|
|
}
|
|
|
|
__bpf_kfunc struct vm_area_struct *bpf_iter_task_vma_next(struct bpf_iter_task_vma *it)
|
|
{
|
|
struct bpf_iter_task_vma_kern *kit = (void *)it;
|
|
|
|
if (!kit->data) /* bpf_iter_task_vma_new failed */
|
|
return NULL;
|
|
return vma_next(&kit->data->vmi);
|
|
}
|
|
|
|
__bpf_kfunc void bpf_iter_task_vma_destroy(struct bpf_iter_task_vma *it)
|
|
{
|
|
struct bpf_iter_task_vma_kern *kit = (void *)it;
|
|
|
|
if (kit->data) {
|
|
bpf_mmap_unlock_mm(kit->data->work, kit->data->mm);
|
|
put_task_struct(kit->data->task);
|
|
bpf_mem_free(&bpf_global_ma, kit->data);
|
|
}
|
|
}
|
|
|
|
__bpf_kfunc_end_defs();
|
|
|
|
#ifdef CONFIG_CGROUPS
|
|
|
|
struct bpf_iter_css_task {
|
|
__u64 __opaque[1];
|
|
} __attribute__((aligned(8)));
|
|
|
|
struct bpf_iter_css_task_kern {
|
|
struct css_task_iter *css_it;
|
|
} __attribute__((aligned(8)));
|
|
|
|
__bpf_kfunc_start_defs();
|
|
|
|
__bpf_kfunc int bpf_iter_css_task_new(struct bpf_iter_css_task *it,
|
|
struct cgroup_subsys_state *css, unsigned int flags)
|
|
{
|
|
struct bpf_iter_css_task_kern *kit = (void *)it;
|
|
|
|
BUILD_BUG_ON(sizeof(struct bpf_iter_css_task_kern) != sizeof(struct bpf_iter_css_task));
|
|
BUILD_BUG_ON(__alignof__(struct bpf_iter_css_task_kern) !=
|
|
__alignof__(struct bpf_iter_css_task));
|
|
kit->css_it = NULL;
|
|
switch (flags) {
|
|
case CSS_TASK_ITER_PROCS | CSS_TASK_ITER_THREADED:
|
|
case CSS_TASK_ITER_PROCS:
|
|
case 0:
|
|
break;
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
|
|
kit->css_it = bpf_mem_alloc(&bpf_global_ma, sizeof(struct css_task_iter));
|
|
if (!kit->css_it)
|
|
return -ENOMEM;
|
|
css_task_iter_start(css, flags, kit->css_it);
|
|
return 0;
|
|
}
|
|
|
|
__bpf_kfunc struct task_struct *bpf_iter_css_task_next(struct bpf_iter_css_task *it)
|
|
{
|
|
struct bpf_iter_css_task_kern *kit = (void *)it;
|
|
|
|
if (!kit->css_it)
|
|
return NULL;
|
|
return css_task_iter_next(kit->css_it);
|
|
}
|
|
|
|
__bpf_kfunc void bpf_iter_css_task_destroy(struct bpf_iter_css_task *it)
|
|
{
|
|
struct bpf_iter_css_task_kern *kit = (void *)it;
|
|
|
|
if (!kit->css_it)
|
|
return;
|
|
css_task_iter_end(kit->css_it);
|
|
bpf_mem_free(&bpf_global_ma, kit->css_it);
|
|
}
|
|
|
|
__bpf_kfunc_end_defs();
|
|
|
|
#endif /* CONFIG_CGROUPS */
|
|
|
|
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 {
|
|
/* all process in the system */
|
|
BPF_TASK_ITER_ALL_PROCS,
|
|
/* all threads in the system */
|
|
BPF_TASK_ITER_ALL_THREADS,
|
|
/* all threads of a specific process */
|
|
BPF_TASK_ITER_PROC_THREADS
|
|
};
|
|
|
|
__bpf_kfunc_start_defs();
|
|
|
|
__bpf_kfunc int bpf_iter_task_new(struct bpf_iter_task *it,
|
|
struct task_struct *task__nullable, 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->pos = NULL;
|
|
|
|
switch (flags) {
|
|
case BPF_TASK_ITER_ALL_THREADS:
|
|
case BPF_TASK_ITER_ALL_PROCS:
|
|
break;
|
|
case BPF_TASK_ITER_PROC_THREADS:
|
|
if (!task__nullable)
|
|
return -EINVAL;
|
|
break;
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (flags == BPF_TASK_ITER_PROC_THREADS)
|
|
kit->task = task__nullable;
|
|
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)
|
|
return pos;
|
|
|
|
if (flags == BPF_TASK_ITER_ALL_PROCS)
|
|
goto get_next_task;
|
|
|
|
kit->pos = __next_thread(kit->pos);
|
|
if (kit->pos || flags == BPF_TASK_ITER_PROC_THREADS)
|
|
return pos;
|
|
|
|
get_next_task:
|
|
kit->task = next_task(kit->task);
|
|
if (kit->task == &init_task)
|
|
kit->pos = NULL;
|
|
else
|
|
kit->pos = kit->task;
|
|
|
|
return pos;
|
|
}
|
|
|
|
__bpf_kfunc void bpf_iter_task_destroy(struct bpf_iter_task *it)
|
|
{
|
|
}
|
|
|
|
__bpf_kfunc_end_defs();
|
|
|
|
DEFINE_PER_CPU(struct mmap_unlock_irq_work, mmap_unlock_work);
|
|
|
|
static void do_mmap_read_unlock(struct irq_work *entry)
|
|
{
|
|
struct mmap_unlock_irq_work *work;
|
|
|
|
if (WARN_ON_ONCE(IS_ENABLED(CONFIG_PREEMPT_RT)))
|
|
return;
|
|
|
|
work = container_of(entry, struct mmap_unlock_irq_work, irq_work);
|
|
mmap_read_unlock_non_owner(work->mm);
|
|
}
|
|
|
|
static int __init task_iter_init(void)
|
|
{
|
|
struct mmap_unlock_irq_work *work;
|
|
int ret, cpu;
|
|
|
|
for_each_possible_cpu(cpu) {
|
|
work = per_cpu_ptr(&mmap_unlock_work, cpu);
|
|
init_irq_work(&work->irq_work, do_mmap_read_unlock);
|
|
}
|
|
|
|
task_reg_info.ctx_arg_info[0].btf_id = btf_tracing_ids[BTF_TRACING_TYPE_TASK];
|
|
ret = bpf_iter_reg_target(&task_reg_info);
|
|
if (ret)
|
|
return ret;
|
|
|
|
task_file_reg_info.ctx_arg_info[0].btf_id = btf_tracing_ids[BTF_TRACING_TYPE_TASK];
|
|
task_file_reg_info.ctx_arg_info[1].btf_id = btf_tracing_ids[BTF_TRACING_TYPE_FILE];
|
|
ret = bpf_iter_reg_target(&task_file_reg_info);
|
|
if (ret)
|
|
return ret;
|
|
|
|
task_vma_reg_info.ctx_arg_info[0].btf_id = btf_tracing_ids[BTF_TRACING_TYPE_TASK];
|
|
task_vma_reg_info.ctx_arg_info[1].btf_id = btf_tracing_ids[BTF_TRACING_TYPE_VMA];
|
|
return bpf_iter_reg_target(&task_vma_reg_info);
|
|
}
|
|
late_initcall(task_iter_init);
|