[PATCH] procfs: Fix listing of /proc/NOT_A_TGID/task
Listing /proc/PID/task were PID is not a TGID should not result in
duplicated entries.
[g ~]$ pidof thunderbird-bin
2751
[g ~]$ ls /proc/2751/task
2751 2770 2771 2824 2826 2834 2835 2851 2853
[g ~]$ ls /proc/2770/task
2751 2770 2771 2824 2826 2834 2835 2851 2853
2770 2771 2824 2826 2834 2835 2851 2853
[g ~]$
Signed-off-by: Guillaume Chazarain <guichaz@yahoo.fr>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/proc/base.c b/fs/proc/base.c
index ff7a668..1a979ea 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2328,13 +2328,23 @@
{
struct dentry *dentry = filp->f_path.dentry;
struct inode *inode = dentry->d_inode;
- struct task_struct *leader = get_proc_task(inode);
+ struct task_struct *leader = NULL;
struct task_struct *task;
int retval = -ENOENT;
ino_t ino;
int tid;
unsigned long pos = filp->f_pos; /* avoiding "long long" filp->f_pos */
+ task = get_proc_task(inode);
+ if (!task)
+ goto out_no_task;
+ rcu_read_lock();
+ if (pid_alive(task)) {
+ leader = task->group_leader;
+ get_task_struct(leader);
+ }
+ rcu_read_unlock();
+ put_task_struct(task);
if (!leader)
goto out_no_task;
retval = 0;