Messages in this thread | | | From | Xuewen Yan <> | Date | Wed, 19 Jul 2023 19:46:29 +0800 | Subject | Re: [PATCH] pid: Add the judgment of whether ns is NULL in the find_pid_ns |
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Dear all
Is there any comment about this patch?
Thanks!
On Thu, Jul 13, 2023 at 3:58 PM Xuewen Yan <xuewen.yan@unisoc.com> wrote: > > There is no the judgment of whether namspace is NULL in find_pid_ns. > But there is a corner case when ns is null, for example: if user > call find_get_pid when current is in exiting, the following stack would > set thread_id be null: > release_task > __exit_signal(p); > __unhash_process(tsk, group_dead); > detach_pid(p, PIDTYPE_PID); > __change_pid(task, type, NULL); > > If user call find_get_pid at now, in find_vpid function, the > task_active_pid_ns would return NULL. As a result, it would be > error when access the ns in find_pid_ns. > > So add the judgment of whether ns is NULL in the find_pid_ns to > prevent this case happen. > > Signed-off-by: Xuewen Yan <xuewen.yan@unisoc.com> > --- > kernel/pid.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/kernel/pid.c b/kernel/pid.c > index 6a1d23a11026..d4a9cb6f3eb9 100644 > --- a/kernel/pid.c > +++ b/kernel/pid.c > @@ -308,6 +308,9 @@ void disable_pid_allocation(struct pid_namespace *ns) > > struct pid *find_pid_ns(int nr, struct pid_namespace *ns) > { > + if (!ns) > + return NULL; > + > return idr_find(&ns->idr, nr); > } > EXPORT_SYMBOL_GPL(find_pid_ns); > -- > 2.25.1 >
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