Messages in this thread Patch in this message | | | Date | Mon, 07 Oct 2013 18:29:11 +0800 | From | Chen Gang <> | Subject | [PATCH] kernel/pid.c: check pid whether be NULL in __change_pid() |
| |
Within __change_pid(), 'new' may be NULL if it comes from detach_pid(), and 'link->pid' also may be NULL ("link->pid = new"), so theoretically,\ the original 'link->pid' may be NULL, too.
In real world, at least now, all callers which will call detach_pid() or change_pid() will not cause issue, but still recommend to check it in __change_pid() to let itself consistency.
After the modification, it passed a simpe test: "build -> boot up -> [s/g]et_[p/s/g]id() test by LTP tools".
Signed-off-by: Chen Gang <gang.chen@asianux.com> --- kernel/pid.c | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-)
diff --git a/kernel/pid.c b/kernel/pid.c index 9b9a266..15b1b3d 100644 --- a/kernel/pid.c +++ b/kernel/pid.c @@ -399,6 +399,9 @@ static void __change_pid(struct task_struct *task, enum pid_type type, hlist_del_rcu(&link->node); link->pid = new; + if (!pid) + return; + for (tmp = PIDTYPE_MAX; --tmp >= 0; ) if (!hlist_empty(&pid->tasks[tmp])) return; -- 1.7.7.6
| |