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Merge branch 'Parameterize task iterators.'

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Kui-Feng Lee says:

====================

Allow creating an iterator that loops through resources of one task/thread.

People could only create iterators to loop through all resources of
files, vma, and tasks in the system, even though they were interested in only the
resources of a specific task or process.  Passing the additional
parameters, people can now create an iterator to go through all
resources or only the resources of a task.

Major Changes:

 - Add new parameters in bpf_iter_link_info to indicate to go through
   all tasks or to go through a specific task.

 - Change the implementations of BPF iterators of vma, files, and
   tasks to allow going through only the resources of a specific task.

 - Provide the arguments of parameterized task iterators in
   bpf_link_info.

Differences from v10:

 - Check pid_alive() to avoid potential errors.

Differences from v9:

  - Fix the boundary check of computing page_shift.

  - Rewording the reason of checking and returning the same task.

Differences from v8:

 - Fix uninitialized variable.

 - Avoid redundant work of getting task from pid.

 - Change format string to use %u instead of %d.

 - Use the value of page_shift to compute correct offset in
   bpf_iter_vm_offset.c.

Differences from v7:

 - Travel the tasks of a process through task_group linked list
   instead of traveling through the whole namespace.

Differences from v6:

 - Add part 5 to make bpftool show the value of parameters.

 - Change of wording of show_fdinfo() to show pid or tid instead of
   always pid.

 - Simplify error handling and naming of test cases.

Differences from v5:

 - Use user-space tid/pid terminologies in bpf_iter_link_info and
   bpf_link_info.

 - Fix reference count

 - Merge all variants to one 'u32 pid' in internal structs.
   (bpf_iter_aux_info and bpf_iter_seq_task_common)

 - Compare the result of get_uprobe_offset() with the implementation
   with the vma iterators.

 - Implement show_fdinfo.

Differences from v4:

 - Remove 'type' from bpf_iter_link_info and bpf_link_info.

v10: https://lore.kernel.org/all/20220831181039.2680134-1-kuifeng@fb.com/
v9: https://lore.kernel.org/bpf/20220829192317.486946-1-kuifeng@fb.com/
v8: https://lore.kernel.org/bpf/20220829192317.486946-1-kuifeng@fb.com/
v7: https://lore.kernel.org/bpf/20220826003712.2810158-1-kuifeng@fb.com/
v6: https://lore.kernel.org/bpf/20220819220927.3409575-1-kuifeng@fb.com/
v5: https://lore.kernel.org/bpf/20220811001654.1316689-1-kuifeng@fb.com/
v4: https://lore.kernel.org/bpf/20220809195429.1043220-1-kuifeng@fb.com/
v3: https://lore.kernel.org/bpf/20220809063501.667610-1-kuifeng@fb.com/
v2: https://lore.kernel.org/bpf/20220801232649.2306614-1-kuifeng@fb.com/
v1: https://lore.kernel.org/bpf/20220726051713.840431-1-kuifeng@fb.com/
====================

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
This commit is contained in:
Andrii Nakryiko 2022-09-28 16:27:55 -07:00
commit aa55dfd378
11 changed files with 588 additions and 46 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
include/linux/bpf.h
View File

@ -1796,6 +1796,27 @@ int bpf_obj_get_user(const char __user *pathname, int flags);
extern int bpf_iter_ ## target(args); \
int __init bpf_iter_ ## target(args) { return 0; }
/*
* The task type of iterators.
*
* For BPF task iterators, they can be parameterized with various
* parameters to visit only some of tasks.
*
* BPF_TASK_ITER_ALL (default)
* Iterate over resources of every task.
*
* BPF_TASK_ITER_TID
* Iterate over resources of a task/tid.
*
* BPF_TASK_ITER_TGID
* Iterate over resources of every task of a process / task group.
*/
enum bpf_iter_task_type {
BPF_TASK_ITER_ALL = 0,
BPF_TASK_ITER_TID,
BPF_TASK_ITER_TGID,
};
struct bpf_iter_aux_info {
/* for map_elem iter */
struct bpf_map *map;
@ -1805,6 +1826,10 @@ struct bpf_iter_aux_info {
struct cgroup *start; /* starting cgroup */
enum bpf_cgroup_iter_order order;
} cgroup;
struct {
enum bpf_iter_task_type type;
u32 pid;
} task;
};
typedef int (*bpf_iter_attach_target_t)(struct bpf_prog *prog,

10
include/uapi/linux/bpf.h
View File

@ -110,6 +110,12 @@ union bpf_iter_link_info {
__u32 cgroup_fd;
__u64 cgroup_id;
} cgroup;
/* Parameters of task iterators. */
struct {
__u32 tid;
__u32 pid;
__u32 pid_fd;
} task;
};
/* BPF syscall commands, see bpf(2) man-page for more details. */
@ -6259,6 +6265,10 @@ struct bpf_link_info {
__u64 cgroup_id;
__u32 order;
} cgroup;
struct {
__u32 tid;
__u32 pid;
} task;
};
} iter;
struct {

224
kernel/bpf/task_iter.c
View File

@ -10,8 +10,17 @@
#include <linux/btf_ids.h>
#include "mmap_unlock_work.h"
static const char * const iter_task_type_names[] = {
"ALL",
"TID",
"PID",
};
struct bpf_iter_seq_task_common {
struct pid_namespace *ns;
enum bpf_iter_task_type type;
u32 pid;
u32 pid_visiting;
};
struct bpf_iter_seq_task_info {
@ -22,18 +31,115 @@ struct bpf_iter_seq_task_info {
u32 tid;
};
static struct task_struct *task_seq_get_next(struct pid_namespace *ns,
static struct task_struct *task_group_seq_get_next(struct bpf_iter_seq_task_common *common,
u32 *tid,
bool skip_if_dup_files)
{
struct task_struct *task, *next_task;
struct pid *pid;
u32 saved_tid;
if (!*tid) {
/* The first time, the iterator calls this function. */
pid = find_pid_ns(common->pid, common->ns);
if (!pid)
return NULL;
task = get_pid_task(pid, PIDTYPE_TGID);
if (!task)
return NULL;
*tid = common->pid;
common->pid_visiting = common->pid;
return task;
}
/* If the control returns to user space and comes back to the
* kernel again, *tid and common->pid_visiting should be the
* same for task_seq_start() to pick up the correct task.
*/
if (*tid == common->pid_visiting) {
pid = find_pid_ns(common->pid_visiting, common->ns);
task = get_pid_task(pid, PIDTYPE_PID);
return task;
}
pid = find_pid_ns(common->pid_visiting, common->ns);
if (!pid)
return NULL;
task = get_pid_task(pid, PIDTYPE_PID);
if (!task)
return NULL;
retry:
if (!pid_alive(task)) {
put_task_struct(task);
return NULL;
}
next_task = next_thread(task);
put_task_struct(task);
if (!next_task)
return NULL;
saved_tid = *tid;
*tid = __task_pid_nr_ns(next_task, PIDTYPE_PID, common->ns);
if (!*tid || *tid == common->pid) {
/* Run out of tasks of a process. The tasks of a
* thread_group are linked as circular linked list.
*/
*tid = saved_tid;
return NULL;
}
get_task_struct(next_task);
common->pid_visiting = *tid;
if (skip_if_dup_files && task->files == task->group_leader->files) {
task = next_task;
goto retry;
}
return next_task;
}
static struct task_struct *task_seq_get_next(struct bpf_iter_seq_task_common *common,
u32 *tid,
bool skip_if_dup_files)
{
struct task_struct *task = NULL;
struct pid *pid;
if (common->type == BPF_TASK_ITER_TID) {
if (*tid && *tid != common->pid)
return NULL;
rcu_read_lock();
pid = find_pid_ns(common->pid, common->ns);
if (pid) {
task = get_pid_task(pid, PIDTYPE_TGID);
*tid = common->pid;
}
rcu_read_unlock();
return task;
}
if (common->type == BPF_TASK_ITER_TGID) {
rcu_read_lock();
task = task_group_seq_get_next(common, tid, skip_if_dup_files);
rcu_read_unlock();
return task;
}
rcu_read_lock();
retry:
pid = find_ge_pid(*tid, ns);
pid = find_ge_pid(*tid, common->ns);
if (pid) {
*tid = pid_nr_ns(pid, ns);
*tid = pid_nr_ns(pid, common->ns);
task = get_pid_task(pid, PIDTYPE_PID);
if (!task) {
++*tid;
@ -56,7 +162,7 @@ static void *task_seq_start(struct seq_file *seq, loff_t *pos)
struct bpf_iter_seq_task_info *info = seq->private;
struct task_struct *task;
task = task_seq_get_next(info->common.ns, &info->tid, false);
task = task_seq_get_next(&info->common, &info->tid, false);
if (!task)
return NULL;
@ -73,7 +179,7 @@ static void *task_seq_next(struct seq_file *seq, void *v, loff_t *pos)
++*pos;
++info->tid;
put_task_struct((struct task_struct *)v);
task = task_seq_get_next(info->common.ns, &info->tid, false);
task = task_seq_get_next(&info->common, &info->tid, false);
if (!task)
return NULL;
@ -117,6 +223,41 @@ static void task_seq_stop(struct seq_file *seq, void *v)
put_task_struct((struct task_struct *)v);
}
static int bpf_iter_attach_task(struct bpf_prog *prog,
union bpf_iter_link_info *linfo,
struct bpf_iter_aux_info *aux)
{
unsigned int flags;
struct pid *pid;
pid_t tgid;
if ((!!linfo->task.tid + !!linfo->task.pid + !!linfo->task.pid_fd) > 1)
return -EINVAL;
aux->task.type = BPF_TASK_ITER_ALL;
if (linfo->task.tid != 0) {
aux->task.type = BPF_TASK_ITER_TID;
aux->task.pid = linfo->task.tid;
}
if (linfo->task.pid != 0) {
aux->task.type = BPF_TASK_ITER_TGID;
aux->task.pid = linfo->task.pid;
}
if (linfo->task.pid_fd != 0) {
aux->task.type = BPF_TASK_ITER_TGID;
pid = pidfd_get_pid(linfo->task.pid_fd, &flags);
if (IS_ERR(pid))
return PTR_ERR(pid);
tgid = pid_nr_ns(pid, task_active_pid_ns(current));
aux->task.pid = tgid;
put_pid(pid);
}
return 0;
}
static const struct seq_operations task_seq_ops = {
.start = task_seq_start,
.next = task_seq_next,
@ -137,8 +278,7 @@ struct bpf_iter_seq_task_file_info {
static struct file *
task_file_seq_get_next(struct bpf_iter_seq_task_file_info *info)
{
struct pid_namespace *ns = info->common.ns;
u32 curr_tid = info->tid;
u32 saved_tid = info->tid;
struct task_struct *curr_task;
unsigned int curr_fd = info->fd;
@ -151,21 +291,18 @@ again:
curr_task = info->task;
curr_fd = info->fd;
} else {
curr_task = task_seq_get_next(ns, &curr_tid, true);
curr_task = task_seq_get_next(&info->common, &info->tid, true);
if (!curr_task) {
info->task = NULL;
info->tid = curr_tid;
return NULL;
}
/* set info->task and info->tid */
/* set info->task */
info->task = curr_task;
if (curr_tid == info->tid) {
if (saved_tid == info->tid)
curr_fd = info->fd;
} else {
info->tid = curr_tid;
else
curr_fd = 0;
}
}
rcu_read_lock();
@ -186,9 +323,15 @@ again:
/* the current task is done, go to the next task */
rcu_read_unlock();
put_task_struct(curr_task);
if (info->common.type == BPF_TASK_ITER_TID) {
info->task = NULL;
return NULL;
}
info->task = NULL;
info->fd = 0;
curr_tid = ++(info->tid);
saved_tid = ++(info->tid);
goto again;
}
@ -269,6 +412,9 @@ static int init_seq_pidns(void *priv_data, struct bpf_iter_aux_info *aux)
struct bpf_iter_seq_task_common *common = priv_data;
common->ns = get_pid_ns(task_active_pid_ns(current));
common->type = aux->task.type;
common->pid = aux->task.pid;
return 0;
}
@ -307,11 +453,10 @@ enum bpf_task_vma_iter_find_op {
static struct vm_area_struct *
task_vma_seq_get_next(struct bpf_iter_seq_task_vma_info *info)
{
struct pid_namespace *ns = info->common.ns;
enum bpf_task_vma_iter_find_op op;
struct vm_area_struct *curr_vma;
struct task_struct *curr_task;
u32 curr_tid = info->tid;
u32 saved_tid = info->tid;
/* If this function returns a non-NULL vma, it holds a reference to
* the task_struct, and holds read lock on vma->mm->mmap_lock.
@ -371,14 +516,13 @@ task_vma_seq_get_next(struct bpf_iter_seq_task_vma_info *info)
}
} else {
again:
curr_task = task_seq_get_next(ns, &curr_tid, true);
curr_task = task_seq_get_next(&info->common, &info->tid, true);
if (!curr_task) {
info->tid = curr_tid + 1;
info->tid++;
goto finish;
}
if (curr_tid != info->tid) {
info->tid = curr_tid;
if (saved_tid != info->tid) {
/* new task, process the first vma */
op = task_vma_iter_first_vma;
} else {
@ -430,9 +574,12 @@ again:
return curr_vma;
next_task:
if (info->common.type == BPF_TASK_ITER_TID)
goto finish;
put_task_struct(curr_task);
info->task = NULL;
curr_tid++;
info->tid++;
goto again;
finish:
@ -531,8 +678,33 @@ static const struct bpf_iter_seq_info task_seq_info = {
.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 = {
@ -540,6 +712,8 @@ static struct bpf_iter_reg task_reg_info = {
PTR_TO_BTF_ID_OR_NULL },
},
.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 = {
@ -551,6 +725,7 @@ static const struct bpf_iter_seq_info task_file_seq_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 = {
@ -560,6 +735,8 @@ static struct bpf_iter_reg task_file_reg_info = {
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 = {
@ -571,6 +748,7 @@ static const struct bpf_iter_seq_info task_vma_seq_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 = {
@ -580,6 +758,8 @@ static struct bpf_iter_reg task_vma_reg_info = {
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,

19
tools/bpf/bpftool/link.c
View File

@ -106,6 +106,13 @@ static const char *cgroup_order_string(__u32 order)
}
}
static bool is_iter_task_target(const char *target_name)
{
return strcmp(target_name, "task") == 0 ||
strcmp(target_name, "task_file") == 0 ||
strcmp(target_name, "task_vma") == 0;
}
static void show_iter_json(struct bpf_link_info *info, json_writer_t *wtr)
{
const char *target_name = u64_to_ptr(info->iter.target_name);
@ -114,6 +121,12 @@ static void show_iter_json(struct bpf_link_info *info, json_writer_t *wtr)
if (is_iter_map_target(target_name))
jsonw_uint_field(wtr, "map_id", info->iter.map.map_id);
else if (is_iter_task_target(target_name)) {
if (info->iter.task.tid)
jsonw_uint_field(wtr, "tid", info->iter.task.tid);
else if (info->iter.task.pid)
jsonw_uint_field(wtr, "pid", info->iter.task.pid);
}
if (is_iter_cgroup_target(target_name)) {
jsonw_lluint_field(wtr, "cgroup_id", info->iter.cgroup.cgroup_id);
@ -237,6 +250,12 @@ static void show_iter_plain(struct bpf_link_info *info)
if (is_iter_map_target(target_name))
printf("map_id %u ", info->iter.map.map_id);
else if (is_iter_task_target(target_name)) {
if (info->iter.task.tid)
printf("tid %u ", info->iter.task.tid);
else if (info->iter.task.pid)
printf("pid %u ", info->iter.task.pid);
}
if (is_iter_cgroup_target(target_name)) {
printf("cgroup_id %llu ", info->iter.cgroup.cgroup_id);

10
tools/include/uapi/linux/bpf.h
View File

@ -110,6 +110,12 @@ union bpf_iter_link_info {
__u32 cgroup_fd;
__u64 cgroup_id;
} cgroup;
/* Parameters of task iterators. */
struct {
__u32 tid;
__u32 pid;
__u32 pid_fd;
} task;
};
/* BPF syscall commands, see bpf(2) man-page for more details. */
@ -6259,6 +6265,10 @@ struct bpf_link_info {
__u64 cgroup_id;
__u32 order;
} cgroup;
struct {
__u32 tid;
__u32 pid;
} task;
};
} iter;
struct {

282
tools/testing/selftests/bpf/prog_tests/bpf_iter.c
View File

@ -1,6 +1,8 @@
// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2020 Facebook */
#include <test_progs.h>
#include <unistd.h>
#include <sys/syscall.h>
#include "bpf_iter_ipv6_route.skel.h"
#include "bpf_iter_netlink.skel.h"
#include "bpf_iter_bpf_map.skel.h"
@ -14,6 +16,7 @@
#include "bpf_iter_udp4.skel.h"
#include "bpf_iter_udp6.skel.h"
#include "bpf_iter_unix.skel.h"
#include "bpf_iter_vma_offset.skel.h"
#include "bpf_iter_test_kern1.skel.h"
#include "bpf_iter_test_kern2.skel.h"
#include "bpf_iter_test_kern3.skel.h"
@ -43,13 +46,13 @@ static void test_btf_id_or_null(void)
}
}
static void do_dummy_read(struct bpf_program *prog)
static void do_dummy_read_opts(struct bpf_program *prog, struct bpf_iter_attach_opts *opts)
{
struct bpf_link *link;
char buf[16] = {};
int iter_fd, len;
link = bpf_program__attach_iter(prog, NULL);
link = bpf_program__attach_iter(prog, opts);
if (!ASSERT_OK_PTR(link, "attach_iter"))
return;
@ -68,6 +71,11 @@ free_link:
bpf_link__destroy(link);
}
static void do_dummy_read(struct bpf_program *prog)
{
do_dummy_read_opts(prog, NULL);
}
static void do_read_map_iter_fd(struct bpf_object_skeleton **skel, struct bpf_program *prog,
struct bpf_map *map)
{
@ -167,19 +175,140 @@ static void test_bpf_map(void)
bpf_iter_bpf_map__destroy(skel);
}
static void test_task(void)
static int pidfd_open(pid_t pid, unsigned int flags)
{
return syscall(SYS_pidfd_open, pid, flags);
}
static void check_bpf_link_info(const struct bpf_program *prog)
{
LIBBPF_OPTS(bpf_iter_attach_opts, opts);
union bpf_iter_link_info linfo;
struct bpf_link_info info = {};
struct bpf_link *link;
__u32 info_len;
int err;
memset(&linfo, 0, sizeof(linfo));
linfo.task.tid = getpid();
opts.link_info = &linfo;
opts.link_info_len = sizeof(linfo);
link = bpf_program__attach_iter(prog, &opts);
if (!ASSERT_OK_PTR(link, "attach_iter"))
return;
info_len = sizeof(info);
err = bpf_obj_get_info_by_fd(bpf_link__fd(link), &info, &info_len);
ASSERT_OK(err, "bpf_obj_get_info_by_fd");
ASSERT_EQ(info.iter.task.tid, getpid(), "check_task_tid");
bpf_link__destroy(link);
}
static pthread_mutex_t do_nothing_mutex;
static void *do_nothing_wait(void *arg)
{
pthread_mutex_lock(&do_nothing_mutex);
pthread_mutex_unlock(&do_nothing_mutex);
pthread_exit(arg);
}
static void test_task_common_nocheck(struct bpf_iter_attach_opts *opts,
int *num_unknown, int *num_known)
{
struct bpf_iter_task *skel;
pthread_t thread_id;
void *ret;
skel = bpf_iter_task__open_and_load();
if (!ASSERT_OK_PTR(skel, "bpf_iter_task__open_and_load"))
return;
do_dummy_read(skel->progs.dump_task);
ASSERT_OK(pthread_mutex_lock(&do_nothing_mutex), "pthread_mutex_lock");
ASSERT_OK(pthread_create(&thread_id, NULL, &do_nothing_wait, NULL),
"pthread_create");
skel->bss->tid = getpid();
do_dummy_read_opts(skel->progs.dump_task, opts);
*num_unknown = skel->bss->num_unknown_tid;
*num_known = skel->bss->num_known_tid;
ASSERT_OK(pthread_mutex_unlock(&do_nothing_mutex), "pthread_mutex_unlock");
ASSERT_FALSE(pthread_join(thread_id, &ret) || ret != NULL,
"pthread_join");
bpf_iter_task__destroy(skel);
}
static void test_task_common(struct bpf_iter_attach_opts *opts, int num_unknown, int num_known)
{
int num_unknown_tid, num_known_tid;
test_task_common_nocheck(opts, &num_unknown_tid, &num_known_tid);
ASSERT_EQ(num_unknown_tid, num_unknown, "check_num_unknown_tid");
ASSERT_EQ(num_known_tid, num_known, "check_num_known_tid");
}
static void test_task_tid(void)
{
LIBBPF_OPTS(bpf_iter_attach_opts, opts);
union bpf_iter_link_info linfo;
int num_unknown_tid, num_known_tid;
memset(&linfo, 0, sizeof(linfo));
linfo.task.tid = getpid();
opts.link_info = &linfo;
opts.link_info_len = sizeof(linfo);
test_task_common(&opts, 0, 1);
linfo.task.tid = 0;
linfo.task.pid = getpid();
test_task_common(&opts, 1, 1);
test_task_common_nocheck(NULL, &num_unknown_tid, &num_known_tid);
ASSERT_GT(num_unknown_tid, 1, "check_num_unknown_tid");
ASSERT_EQ(num_known_tid, 1, "check_num_known_tid");
}
static void test_task_pid(void)
{
LIBBPF_OPTS(bpf_iter_attach_opts, opts);
union bpf_iter_link_info linfo;
memset(&linfo, 0, sizeof(linfo));
linfo.task.pid = getpid();
opts.link_info = &linfo;
opts.link_info_len = sizeof(linfo);
test_task_common(&opts, 1, 1);
}
static void test_task_pidfd(void)
{
LIBBPF_OPTS(bpf_iter_attach_opts, opts);
union bpf_iter_link_info linfo;
int pidfd;
pidfd = pidfd_open(getpid(), 0);
if (!ASSERT_GT(pidfd, 0, "pidfd_open"))
return;
memset(&linfo, 0, sizeof(linfo));
linfo.task.pid_fd = pidfd;
opts.link_info = &linfo;
opts.link_info_len = sizeof(linfo);
test_task_common(&opts, 1, 1);
close(pidfd);
}
static void test_task_sleepable(void)
{
struct bpf_iter_task *skel;
@ -212,14 +341,11 @@ static void test_task_stack(void)
bpf_iter_task_stack__destroy(skel);
}
static void *do_nothing(void *arg)
{
pthread_exit(arg);
}
static void test_task_file(void)
{
LIBBPF_OPTS(bpf_iter_attach_opts, opts);
struct bpf_iter_task_file *skel;
union bpf_iter_link_info linfo;
pthread_t thread_id;
void *ret;
@ -229,19 +355,36 @@ static void test_task_file(void)
skel->bss->tgid = getpid();
if (!ASSERT_OK(pthread_create(&thread_id, NULL, &do_nothing, NULL),
"pthread_create"))
goto done;
ASSERT_OK(pthread_mutex_lock(&do_nothing_mutex), "pthread_mutex_lock");
ASSERT_OK(pthread_create(&thread_id, NULL, &do_nothing_wait, NULL),
"pthread_create");
memset(&linfo, 0, sizeof(linfo));
linfo.task.tid = getpid();
opts.link_info = &linfo;
opts.link_info_len = sizeof(linfo);
do_dummy_read_opts(skel->progs.dump_task_file, &opts);
ASSERT_EQ(skel->bss->count, 0, "check_count");
ASSERT_EQ(skel->bss->unique_tgid_count, 1, "check_unique_tgid_count");
skel->bss->last_tgid = 0;
skel->bss->count = 0;
skel->bss->unique_tgid_count = 0;
do_dummy_read(skel->progs.dump_task_file);
if (!ASSERT_FALSE(pthread_join(thread_id, &ret) || ret != NULL,
"pthread_join"))
goto done;
ASSERT_EQ(skel->bss->count, 0, "check_count");
ASSERT_GT(skel->bss->unique_tgid_count, 1, "check_unique_tgid_count");
check_bpf_link_info(skel->progs.dump_task_file);
ASSERT_OK(pthread_mutex_unlock(&do_nothing_mutex), "pthread_mutex_unlock");
ASSERT_OK(pthread_join(thread_id, &ret), "pthread_join");
ASSERT_NULL(ret, "pthread_join");
done:
bpf_iter_task_file__destroy(skel);
}
@ -1249,7 +1392,7 @@ static void str_strip_first_line(char *str)
*dst = '\0';
}
static void test_task_vma(void)
static void test_task_vma_common(struct bpf_iter_attach_opts *opts)
{
int err, iter_fd = -1, proc_maps_fd = -1;
struct bpf_iter_task_vma *skel;
@ -1261,13 +1404,14 @@ static void test_task_vma(void)
return;
skel->bss->pid = getpid();
skel->bss->one_task = opts ? 1 : 0;
err = bpf_iter_task_vma__load(skel);
if (!ASSERT_OK(err, "bpf_iter_task_vma__load"))
goto out;
skel->links.proc_maps = bpf_program__attach_iter(
skel->progs.proc_maps, NULL);
skel->progs.proc_maps, opts);
if (!ASSERT_OK_PTR(skel->links.proc_maps, "bpf_program__attach_iter")) {
skel->links.proc_maps = NULL;
@ -1291,6 +1435,8 @@ static void test_task_vma(void)
goto out;
len += err;
}
if (opts)
ASSERT_EQ(skel->bss->one_task_error, 0, "unexpected task");
/* read CMP_BUFFER_SIZE (1kB) from /proc/pid/maps */
snprintf(maps_path, 64, "/proc/%u/maps", skel->bss->pid);
@ -1306,6 +1452,9 @@ static void test_task_vma(void)
str_strip_first_line(proc_maps_output);
ASSERT_STREQ(task_vma_output, proc_maps_output, "compare_output");
check_bpf_link_info(skel->progs.proc_maps);
out:
close(proc_maps_fd);
close(iter_fd);
@ -1325,8 +1474,93 @@ void test_bpf_sockmap_map_iter_fd(void)
bpf_iter_sockmap__destroy(skel);
}
static void test_task_vma(void)
{
LIBBPF_OPTS(bpf_iter_attach_opts, opts);
union bpf_iter_link_info linfo;
memset(&linfo, 0, sizeof(linfo));
linfo.task.tid = getpid();
opts.link_info = &linfo;
opts.link_info_len = sizeof(linfo);
test_task_vma_common(&opts);
test_task_vma_common(NULL);
}
/* uprobe attach point */
static noinline int trigger_func(int arg)
{
asm volatile ("");
return arg + 1;
}
static void test_task_vma_offset_common(struct bpf_iter_attach_opts *opts, bool one_proc)
{
struct bpf_iter_vma_offset *skel;
struct bpf_link *link;
char buf[16] = {};
int iter_fd, len;
int pgsz, shift;
skel = bpf_iter_vma_offset__open_and_load();
if (!ASSERT_OK_PTR(skel, "bpf_iter_vma_offset__open_and_load"))
return;
skel->bss->pid = getpid();
skel->bss->address = (uintptr_t)trigger_func;
for (pgsz = getpagesize(), shift = 0; pgsz > 1; pgsz >>= 1, shift++)
;
skel->bss->page_shift = shift;
link = bpf_program__attach_iter(skel->progs.get_vma_offset, opts);
if (!ASSERT_OK_PTR(link, "attach_iter"))
return;
iter_fd = bpf_iter_create(bpf_link__fd(link));
if (!ASSERT_GT(iter_fd, 0, "create_iter"))
goto exit;
while ((len = read(iter_fd, buf, sizeof(buf))) > 0)
;
buf[15] = 0;
ASSERT_EQ(strcmp(buf, "OK\n"), 0, "strcmp");
ASSERT_EQ(skel->bss->offset, get_uprobe_offset(trigger_func), "offset");
if (one_proc)
ASSERT_EQ(skel->bss->unique_tgid_cnt, 1, "unique_tgid_count");
else
ASSERT_GT(skel->bss->unique_tgid_cnt, 1, "unique_tgid_count");
close(iter_fd);
exit:
bpf_link__destroy(link);
}
static void test_task_vma_offset(void)
{
LIBBPF_OPTS(bpf_iter_attach_opts, opts);
union bpf_iter_link_info linfo;
memset(&linfo, 0, sizeof(linfo));
linfo.task.pid = getpid();
opts.link_info = &linfo;
opts.link_info_len = sizeof(linfo);
test_task_vma_offset_common(&opts, true);
linfo.task.pid = 0;
linfo.task.tid = getpid();
test_task_vma_offset_common(&opts, true);
test_task_vma_offset_common(NULL, false);
}
void test_bpf_iter(void)
{
ASSERT_OK(pthread_mutex_init(&do_nothing_mutex, NULL), "pthread_mutex_init");
if (test__start_subtest("btf_id_or_null"))
test_btf_id_or_null();
if (test__start_subtest("ipv6_route"))
@ -1335,8 +1569,12 @@ void test_bpf_iter(void)
test_netlink();
if (test__start_subtest("bpf_map"))
test_bpf_map();
if (test__start_subtest("task"))
test_task();
if (test__start_subtest("task_tid"))
test_task_tid();
if (test__start_subtest("task_pid"))
test_task_pid();
if (test__start_subtest("task_pidfd"))
test_task_pidfd();
if (test__start_subtest("task_sleepable"))
test_task_sleepable();
if (test__start_subtest("task_stack"))
@ -1397,4 +1635,6 @@ void test_bpf_iter(void)
test_ksym_iter();
if (test__start_subtest("bpf_sockmap_map_iter_fd"))
test_bpf_sockmap_map_iter_fd();
if (test__start_subtest("vma_offset"))
test_task_vma_offset();
}

2
tools/testing/selftests/bpf/prog_tests/btf_dump.c
View File

@ -764,7 +764,7 @@ static void test_btf_dump_struct_data(struct btf *btf, struct btf_dump *d,
/* union with nested struct */
TEST_BTF_DUMP_DATA(btf, d, "union", str, union bpf_iter_link_info, BTF_F_COMPACT,
"(union bpf_iter_link_info){.map = (struct){.map_fd = (__u32)1,},.cgroup = (struct){.order = (enum bpf_cgroup_iter_order)BPF_CGROUP_ITER_SELF_ONLY,.cgroup_fd = (__u32)1,},}",
"(union bpf_iter_link_info){.map = (struct){.map_fd = (__u32)1,},.cgroup = (struct){.order = (enum bpf_cgroup_iter_order)BPF_CGROUP_ITER_SELF_ONLY,.cgroup_fd = (__u32)1,},.task = (struct){.tid = (__u32)1,.pid = (__u32)1,},}",
{ .cgroup = { .order = 1, .cgroup_fd = 1, }});
/* struct skb with nested structs/unions; because type output is so

9
tools/testing/selftests/bpf/progs/bpf_iter_task.c
View File

@ -6,6 +6,10 @@
char _license[] SEC("license") = "GPL";
uint32_t tid = 0;
int num_unknown_tid = 0;
int num_known_tid = 0;
SEC("iter/task")
int dump_task(struct bpf_iter__task *ctx)
{
@ -18,6 +22,11 @@ int dump_task(struct bpf_iter__task *ctx)
return 0;
}
if (task->pid != tid)
num_unknown_tid++;
else
num_known_tid++;
if (ctx->meta->seq_num == 0)
BPF_SEQ_PRINTF(seq, " tgid gid\n");

9
tools/testing/selftests/bpf/progs/bpf_iter_task_file.c
View File

@ -7,14 +7,16 @@ char _license[] SEC("license") = "GPL";
int count = 0;
int tgid = 0;
int last_tgid = 0;
int unique_tgid_count = 0;
SEC("iter/task_file")
int dump_task_file(struct bpf_iter__task_file *ctx)
{
struct seq_file *seq = ctx->meta->seq;
struct task_struct *task = ctx->task;
__u32 fd = ctx->fd;
struct file *file = ctx->file;
__u32 fd = ctx->fd;
if (task == (void *)0 || file == (void *)0)
return 0;
@ -27,6 +29,11 @@ int dump_task_file(struct bpf_iter__task_file *ctx)
if (tgid == task->tgid && task->tgid != task->pid)
count++;
if (last_tgid != task->tgid) {
last_tgid = task->tgid;
unique_tgid_count++;
}
BPF_SEQ_PRINTF(seq, "%8d %8d %8d %lx\n", task->tgid, task->pid, fd,
(long)file->f_op);
return 0;

7
tools/testing/selftests/bpf/progs/bpf_iter_task_vma.c
View File

@ -20,6 +20,8 @@ char _license[] SEC("license") = "GPL";
#define D_PATH_BUF_SIZE 1024
char d_path_buf[D_PATH_BUF_SIZE] = {};
__u32 pid = 0;
__u32 one_task = 0;
__u32 one_task_error = 0;
SEC("iter/task_vma") int proc_maps(struct bpf_iter__task_vma *ctx)
{
@ -33,8 +35,11 @@ SEC("iter/task_vma") int proc_maps(struct bpf_iter__task_vma *ctx)
return 0;
file = vma->vm_file;
if (task->tgid != pid)
if (task->tgid != pid) {
if (one_task)
one_task_error = 1;
return 0;
}
perm_str[0] = (vma->vm_flags & VM_READ) ? 'r' : '-';
perm_str[1] = (vma->vm_flags & VM_WRITE) ? 'w' : '-';
perm_str[2] = (vma->vm_flags & VM_EXEC) ? 'x' : '-';

37
tools/testing/selftests/bpf/progs/bpf_iter_vma_offset.c Normal file
View File

@ -0,0 +1,37 @@
// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
#include "bpf_iter.h"
#include <bpf/bpf_helpers.h>
char _license[] SEC("license") = "GPL";
__u32 unique_tgid_cnt = 0;
uintptr_t address = 0;
uintptr_t offset = 0;
__u32 last_tgid = 0;
__u32 pid = 0;
__u32 page_shift = 0;
SEC("iter/task_vma")
int get_vma_offset(struct bpf_iter__task_vma *ctx)
{
struct vm_area_struct *vma = ctx->vma;
struct seq_file *seq = ctx->meta->seq;
struct task_struct *task = ctx->task;
if (task == NULL || vma == NULL)
return 0;
if (last_tgid != task->tgid)
unique_tgid_cnt++;
last_tgid = task->tgid;
if (task->tgid != pid)
return 0;
if (vma->vm_start <= address && vma->vm_end > address) {
offset = address - vma->vm_start + (vma->vm_pgoff << page_shift);
BPF_SEQ_PRINTF(seq, "OK\n");
}
return 0;
}