diff options
| author | Oleg Nesterov <oleg@redhat.com> | 2017-08-21 17:35:02 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-08-24 17:02:36 -0700 |
| commit | b4cf49024cf412a94121e61f8056636c557ead98 (patch) | |
| tree | 38a9cdf76224f841d41faff29b57a51a90e6c3c4 /include/linux/pid.h | |
| parent | 46d51a26efbc7cbaa2bc1f01628a00a604193856 (diff) | |
pids: make task_tgid_nr_ns() safe
commit dd1c1f2f2028a7b851f701fc6a8ebe39dcb95e7c upstream.
This was reported many times, and this was even mentioned in commit
52ee2dfdd4f5 ("pids: refactor vnr/nr_ns helpers to make them safe") but
somehow nobody bothered to fix the obvious problem: task_tgid_nr_ns() is
not safe because task->group_leader points to nowhere after the exiting
task passes exit_notify(), rcu_read_lock() can not help.
We really need to change __unhash_process() to nullify group_leader,
parent, and real_parent, but this needs some cleanups. Until then we
can turn task_tgid_nr_ns() into another user of __task_pid_nr_ns() and
fix the problem.
Reported-by: Troy Kensinger <tkensinger@google.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/linux/pid.h')
| -rw-r--r-- | include/linux/pid.h | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/include/linux/pid.h b/include/linux/pid.h index 23705a53abba..97b745ddece5 100644 --- a/include/linux/pid.h +++ b/include/linux/pid.h @@ -8,7 +8,9 @@ enum pid_type PIDTYPE_PID, PIDTYPE_PGID, PIDTYPE_SID, - PIDTYPE_MAX + PIDTYPE_MAX, + /* only valid to __task_pid_nr_ns() */ + __PIDTYPE_TGID }; /* |