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Commit 9cc8cbc7 authored by Eric W. Biederman's avatar Eric W. Biederman Committed by Linus Torvalds
Browse files

[PATCH] simply fix first_tgid 



Like the bug Oleg spotted in first_tid there was also a small off by one
error in first_tgid, when a seek was done on the /proc directory.  This
fixes that and changes the code structure to make it a little more obvious
what is going on.

Signed-off-by: default avatarEric W. Biederman <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent de758734

fs/proc/base.c

+13 −15
Original line number Diff line number Diff line
@@ -2040,34 +2040,32 @@ out: 
 * In the case of a seek we start with &init_task and walk nr

 * threads past it.

 */

static struct task_struct *first_tgid(int tgid, int nr)

static struct task_struct *first_tgid(int tgid, unsigned int nr)

{

	struct task_struct *pos = NULL;

	struct task_struct *pos;

	rcu_read_lock();

	if (tgid && nr) {

		pos = find_task_by_pid(tgid);

		if (pos && !thread_group_leader(pos))

			pos = NULL;

		if (pos)

			nr = 0;

		if (pos && thread_group_leader(pos))

			goto found;

	}

	/* If nr exceeds the number of processes get out quickly */

	pos = NULL;

	if (nr && nr >= nr_processes())

		goto done;



	/* If we haven't found our starting place yet start with

	 * the init_task and walk nr tasks forward.

	 */

	if (!pos && (nr >= 0))

		pos = next_task(&init_task);



	for (; pos && pid_alive(pos); pos = next_task(pos)) {

		if (--nr > 0)

			continue;

		get_task_struct(pos);

	for (pos = next_task(&init_task); nr > 0; --nr) {

		pos = next_task(pos);

		if (pos == &init_task) {

			pos = NULL;

			goto done;

		}

	pos = NULL;

	}

found:

	get_task_struct(pos);

done:

	rcu_read_unlock();

	return pos;