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authorOleg Nesterov <oleg@redhat.com>2014-01-24 00:55:38 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2014-01-24 01:37:01 +0100
commitc986c14a6a88427946dc77d7018a81b95b3d41b6 (patch)
treeaf9183f50ca1b002745a491f5d9bc1f2d4b84c78 /fs
parentproc: fix the potential use-after-free in first_tid() (diff)
downloadlinux-c986c14a6a88427946dc77d7018a81b95b3d41b6.tar.xz
linux-c986c14a6a88427946dc77d7018a81b95b3d41b6.zip
proc: change first_tid() to use while_each_thread() rather than next_thread()
Rerwrite the main loop to use while_each_thread() instead of next_thread(). We are going to fix or replace while_each_thread(), next_thread() should be avoided whenever possible. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Sameer Nanda <snanda@chromium.org> Cc: Sergey Dyasly <dserrg@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/proc/base.c20
1 files changed, 10 insertions, 10 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c
index f223a56e613c..be8e17cabfc7 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -3106,23 +3106,23 @@ static struct task_struct *first_tid(struct task_struct *leader,
}
/* If nr exceeds the number of threads there is nothing todo */
- pos = NULL;
if (nr && nr >= get_nr_threads(leader))
- goto out;
+ goto fail;
/* It could be unhashed before we take rcu lock */
if (!pid_alive(leader))
- goto out;
+ goto fail;
/* If we haven't found our starting place yet start
* with the leader and walk nr threads forward.
*/
- for (pos = leader; nr > 0; --nr) {
- pos = next_thread(pos);
- if (pos == leader) {
- pos = NULL;
- goto out;
- }
- }
+ pos = leader;
+ do {
+ if (nr-- <= 0)
+ goto found;
+ } while_each_thread(leader, pos);
+fail:
+ pos = NULL;
+ goto out;
found:
get_task_struct(pos);
out: