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.c...@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
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