[PATCH] procfs: Fix hardlink counts for /proc/<PID>/task

The current logic assumes that a /proc/<PID>/task directory should have a
hardlink count of 3, probably counting ".", "..", and a directory for a
single child task.

It's fairly obvious that this doesn't work out correctly when a PID has
more than one child task, which is quite often the case.

Signed-off-by: Daniel Drake <dsd@gentoo.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 6 insertions, 2 deletions

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 4718173af2c8..2eac86d46c51 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1419,6 +1419,8 @@ static struct file_operations proc_tgid_attr_operations;
 static struct inode_operations proc_tgid_attr_inode_operations;
 #endif
 
+static int get_tid_list(int index, unsigned int *tids, struct inode *dir);
+
 /* SMP-safe */
 static struct dentry *proc_pident_lookup(struct inode *dir, 
                                          struct dentry *dentry,
@@ -1458,7 +1460,7 @@ static struct dentry *proc_pident_lookup(struct inode *dir,
          */
         switch(p->type) {
                 case PROC_TGID_TASK:
-                        inode->i_nlink = 3;
+                        inode->i_nlink = 2 + get_tid_list(2, NULL, dir);
                         inode->i_op = &proc_task_inode_operations;
                         inode->i_fop = &proc_task_operations;
                         break;
@@ -1943,7 +1945,8 @@ static int get_tid_list(int index, unsigned int *tids, struct inode *dir)
 
                 if (--index >= 0)
                         continue;
-                tids[nr_tids] = tid;
+                if (tids != NULL)
+                        tids[nr_tids] = tid;
                 nr_tids++;
                 if (nr_tids >= PROC_MAXPIDS)
                         break;
@@ -2043,6 +2046,7 @@ static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldi
         }
 
         nr_tids = get_tid_list(pos, tid_array, inode);
+        inode->i_nlink = pos + nr_tids;
 
         for (i = 0; i < nr_tids; i++) {
                 unsigned long j = PROC_NUMBUF;