diff mbox series

[bpf-next,v7,1/5] bpf: Parameterize task iterators.

Message ID 20220826003712.2810158-2-kuifeng@fb.com (mailing list archive)
State Superseded
Delegated to: BPF
Headers show
Series Parameterize task iterators. | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for bpf-next, async
netdev/apply fail Patch does not apply to bpf-next
bpf/vmtest-bpf-next-PR success PR summary
bpf/vmtest-bpf-next-VM_Test-1 success Logs for build for s390x with gcc
bpf/vmtest-bpf-next-VM_Test-2 success Logs for build for x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-3 success Logs for build for x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-4 success Logs for llvm-toolchain
bpf/vmtest-bpf-next-VM_Test-5 success Logs for set-matrix
bpf/vmtest-bpf-next-VM_Test-6 success Logs for test_maps on s390x with gcc
bpf/vmtest-bpf-next-VM_Test-7 success Logs for test_maps on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-8 success Logs for test_maps on x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-9 success Logs for test_progs on s390x with gcc
bpf/vmtest-bpf-next-VM_Test-10 success Logs for test_progs on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-11 success Logs for test_progs on x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-12 success Logs for test_progs_no_alu32 on s390x with gcc
bpf/vmtest-bpf-next-VM_Test-13 success Logs for test_progs_no_alu32 on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-14 success Logs for test_progs_no_alu32 on x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-15 success Logs for test_verifier on s390x with gcc
bpf/vmtest-bpf-next-VM_Test-16 success Logs for test_verifier on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-17 success Logs for test_verifier on x86_64 with llvm-16

Commit Message

Kui-Feng Lee Aug. 26, 2022, 12:37 a.m. UTC 
Allow creating an iterator that loops through resources of one
thread/process.

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.

Signed-off-by: Kui-Feng Lee <kuifeng@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
---
 include/linux/bpf.h            |  25 +++++++
 include/uapi/linux/bpf.h       |   6 ++
 kernel/bpf/task_iter.c         | 128 ++++++++++++++++++++++++++-------
 tools/include/uapi/linux/bpf.h |   6 ++
 4 files changed, 141 insertions(+), 24 deletions(-)

Comments

Yonghong Song Aug. 26, 2022, 7:30 p.m. UTC | #1 
On 8/25/22 5:37 PM, Kui-Feng Lee wrote:
> Allow creating an iterator that loops through resources of one
> thread/process.
> 
> 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.
> 
> Signed-off-by: Kui-Feng Lee <kuifeng@fb.com>
> Acked-by: Yonghong Song <yhs@fb.com>
> ---
>   include/linux/bpf.h            |  25 +++++++
>   include/uapi/linux/bpf.h       |   6 ++
>   kernel/bpf/task_iter.c         | 128 ++++++++++++++++++++++++++-------
>   tools/include/uapi/linux/bpf.h |   6 ++
>   4 files changed, 141 insertions(+), 24 deletions(-)
> 
> diff --git a/include/linux/bpf.h b/include/linux/bpf.h
> index 9c1674973e03..31ac2c1181f5 100644
> --- a/include/linux/bpf.h
> +++ b/include/linux/bpf.h
> @@ -1730,6 +1730,27 @@ 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;
> @@ -1739,6 +1760,10 @@ 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,
> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index 0f61f09f467a..385deab984e1 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -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. */
> diff --git a/kernel/bpf/task_iter.c b/kernel/bpf/task_iter.c
> index 8c921799def4..1200cfde71e3 100644
> --- a/kernel/bpf/task_iter.c
> +++ b/kernel/bpf/task_iter.c
> @@ -12,6 +12,8 @@
>   
>   struct bpf_iter_seq_task_common {
>   	struct pid_namespace *ns;
> +	enum bpf_iter_task_type	type;
> +	u32 pid;
>   };
>   
>   struct bpf_iter_seq_task_info {
> @@ -22,24 +24,54 @@ struct bpf_iter_seq_task_info {
>   	u32 tid;
>   };
>   
> -static struct task_struct *task_seq_get_next(struct pid_namespace *ns,
> +static bool matched_task(struct task_struct *task,
> +			 struct bpf_iter_seq_task_common *common,
> +			 bool skip_if_dup_file)
> +{
> +	/* Should not have the same 'files' if skip_if_dup_file is true */
> +	bool diff_files_if =
> +		!skip_if_dup_file ||
> +		(thread_group_leader(task) &&
> +		 task->files != task->group_leader->files);

Should this be
	!skip_if_dup_file || thread_group_leader(task) ||
	task->files != task->group_leader->files
?

> +	/* Should have the given tgid if the type is BPF_TASK_ITER_TGI */

BPF_TASK_ITER_TGID?

> +	bool have_tgid_if =
> +		common->type != BPF_TASK_ITER_TGID ||
> +		__task_pid_nr_ns(task, PIDTYPE_TGID,
> +				 common->ns) == common->pid;
> +	return diff_files_if && have_tgid_if;
> +}
> +
> +
> +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_PID);
> +			*tid = common->pid;
> +		}
> +		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;
>   			goto retry;
> -		} else if (skip_if_dup_files && !thread_group_leader(task) &&
> -			   task->files == task->group_leader->files) {
> +		} else if (!matched_task(task, common, skip_if_dup_files)) {
>   			put_task_struct(task);
>   			task = NULL;
>   			++*tid;
> @@ -56,7 +88,7 @@ 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;
>   
[...]
Kui-Feng Lee Aug. 27, 2022, 6:29 p.m. UTC | #2 
On Fri, 2022-08-26 at 12:30 -0700, Yonghong Song wrote:
> 
> 
> On 8/25/22 5:37 PM, Kui-Feng Lee wrote:
> > Allow creating an iterator that loops through resources of one
> > thread/process.
> > 
> > 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.
> > 
> > Signed-off-by: Kui-Feng Lee <kuifeng@fb.com>
> > Acked-by: Yonghong Song <yhs@fb.com>
> > ---
> >   include/linux/bpf.h            |  25 +++++++
> >   include/uapi/linux/bpf.h       |   6 ++
> >   kernel/bpf/task_iter.c         | 128 ++++++++++++++++++++++++++--
> > -----
> >   tools/include/uapi/linux/bpf.h |   6 ++
> >   4 files changed, 141 insertions(+), 24 deletions(-)
> > 
> > diff --git a/include/linux/bpf.h b/include/linux/bpf.h
> > index 9c1674973e03..31ac2c1181f5 100644
> > --- a/include/linux/bpf.h
> > +++ b/include/linux/bpf.h
> > @@ -1730,6 +1730,27 @@ 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;
> > @@ -1739,6 +1760,10 @@ 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,
> > diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> > index 0f61f09f467a..385deab984e1 100644
> > --- a/include/uapi/linux/bpf.h
> > +++ b/include/uapi/linux/bpf.h
> > @@ -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. */
> > diff --git a/kernel/bpf/task_iter.c b/kernel/bpf/task_iter.c
> > index 8c921799def4..1200cfde71e3 100644
> > --- a/kernel/bpf/task_iter.c
> > +++ b/kernel/bpf/task_iter.c
> > @@ -12,6 +12,8 @@
> >   
> >   struct bpf_iter_seq_task_common {
> >         struct pid_namespace *ns;
> > +       enum bpf_iter_task_type type;
> > +       u32 pid;
> >   };
> >   
> >   struct bpf_iter_seq_task_info {
> > @@ -22,24 +24,54 @@ struct bpf_iter_seq_task_info {
> >         u32 tid;
> >   };
> >   
> > -static struct task_struct *task_seq_get_next(struct pid_namespace
> > *ns,
> > +static bool matched_task(struct task_struct *task,
> > +                        struct bpf_iter_seq_task_common *common,
> > +                        bool skip_if_dup_file)
> > +{
> > +       /* Should not have the same 'files' if skip_if_dup_file is
> > true */
> > +       bool diff_files_if =
> > +               !skip_if_dup_file ||
> > +               (thread_group_leader(task) &&
> > +                task->files != task->group_leader->files);
> 
> Should this be
>         !skip_if_dup_file || thread_group_leader(task) ||
>         task->files != task->group_leader->files
> ?

Good catch!
This change will be rollbacked by using next_thread().

> 
> > +       /* Should have the given tgid if the type is
> > BPF_TASK_ITER_TGI */
> 
> BPF_TASK_ITER_TGID?
> 
> > +       bool have_tgid_if =
> > +               common->type != BPF_TASK_ITER_TGID ||
> > +               __task_pid_nr_ns(task, PIDTYPE_TGID,
> > +                                common->ns) == common->pid;
> > +       return diff_files_if && have_tgid_if;
> > +}
> > +
> > +
> > +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_PID);
> > +                       *tid = common->pid;
> > +               }
> > +               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;
> >                         goto retry;
> > -               } else if (skip_if_dup_files &&
> > !thread_group_leader(task) &&
> > -                          task->files == task->group_leader-
> > >files) {
> > +               } else if (!matched_task(task, common,
> > skip_if_dup_files)) {
> >                         put_task_struct(task);
> >                         task = NULL;
> >                         ++*tid;
> > @@ -56,7 +88,7 @@ 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;
> >   
> [...]
diff mbox series

Patch

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 9c1674973e03..31ac2c1181f5 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1730,6 +1730,27 @@  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;
@@ -1739,6 +1760,10 @@  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,
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 0f61f09f467a..385deab984e1 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -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. */
diff --git a/kernel/bpf/task_iter.c b/kernel/bpf/task_iter.c
index 8c921799def4..1200cfde71e3 100644
--- a/kernel/bpf/task_iter.c
+++ b/kernel/bpf/task_iter.c
@@ -12,6 +12,8 @@ 
 
 struct bpf_iter_seq_task_common {
 	struct pid_namespace *ns;
+	enum bpf_iter_task_type	type;
+	u32 pid;
 };
 
 struct bpf_iter_seq_task_info {
@@ -22,24 +24,54 @@  struct bpf_iter_seq_task_info {
 	u32 tid;
 };
 
-static struct task_struct *task_seq_get_next(struct pid_namespace *ns,
+static bool matched_task(struct task_struct *task,
+			 struct bpf_iter_seq_task_common *common,
+			 bool skip_if_dup_file)
+{
+	/* Should not have the same 'files' if skip_if_dup_file is true */
+	bool diff_files_if =
+		!skip_if_dup_file ||
+		(thread_group_leader(task) &&
+		 task->files != task->group_leader->files);
+	/* Should have the given tgid if the type is BPF_TASK_ITER_TGI */
+	bool have_tgid_if =
+		common->type != BPF_TASK_ITER_TGID ||
+		__task_pid_nr_ns(task, PIDTYPE_TGID,
+				 common->ns) == common->pid;
+	return diff_files_if && have_tgid_if;
+}
+
+
+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_PID);
+			*tid = common->pid;
+		}
+		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;
 			goto retry;
-		} else if (skip_if_dup_files && !thread_group_leader(task) &&
-			   task->files == task->group_leader->files) {
+		} else if (!matched_task(task, common, skip_if_dup_files)) {
 			put_task_struct(task);
 			task = NULL;
 			++*tid;
@@ -56,7 +88,7 @@  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 +105,7 @@  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 +149,45 @@  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_namespace *ns;
+	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;
+		ns = task_active_pid_ns(current);
+		if (IS_ERR(ns))
+			return PTR_ERR(ns);
+
+		pid = pidfd_get_pid(linfo->task.pid_fd, &flags);
+		if (IS_ERR(pid))
+			return PTR_ERR(pid);
+
+		tgid = pid_nr_ns(pid, ns);
+		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 +208,7 @@  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 +221,18 @@  task_file_seq_get_next(struct bpf_iter_seq_task_file_info *info)
 		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 +253,15 @@  task_file_seq_get_next(struct bpf_iter_seq_task_file_info *info)
 	/* 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 +342,9 @@  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 +383,10 @@  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 +446,13 @@  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 +504,12 @@  task_vma_seq_get_next(struct bpf_iter_seq_task_vma_info *info)
 	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:
@@ -533,6 +610,7 @@  static const struct bpf_iter_seq_info task_seq_info = {
 
 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		= {
@@ -551,6 +629,7 @@  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		= {
@@ -571,6 +650,7 @@  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		= {
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 5056cef2112f..a54a1455333c 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -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. */