Messages in this thread | | | From | Yafang Shao <> | Date | Thu, 30 Sep 2021 20:54:10 +0800 | Subject | Re: [PATCH 5/5] kernel/kthread: show a warning if kthread's comm is still trucated |
| |
On Thu, Sep 30, 2021 at 2:20 AM Kees Cook <keescook@chromium.org> wrote: > > On Wed, Sep 29, 2021 at 11:50:36AM +0000, Yafang Shao wrote: > > Show a warning if the ktrhead's comm is still trucated. Below is the > > result of my test case - > > > > __kthread_create_on_node:410: comm of pid 14 is truncated from "I-am-a-kthread-with-long-name" to "I-am-a-kthread-with-lon" > > > > Signed-off-by: Yafang Shao <laoar.shao@gmail.com> > > I like this check as a reasonable way to make kthread authors aware of > the TASK_COMM_LEN limitation. >
Thanks for the review.
> > --- > > kernel/kthread.c | 6 +++++- > > 1 file changed, 5 insertions(+), 1 deletion(-) > > > > diff --git a/kernel/kthread.c b/kernel/kthread.c > > index 6def951c605a..aa093f1f423a 100644 > > --- a/kernel/kthread.c > > +++ b/kernel/kthread.c > > @@ -404,7 +404,11 @@ struct task_struct *__kthread_create_on_node(int (*threadfn)(void *data), > > * task is already visible to other tasks, so updating > > * COMM must be protected. > > */ > > - vsnprintf(name, sizeof(name), namefmt, args); > > + if (vsnprintf(name, KTHREAD_COMM_LEN, namefmt, args) >= > > + KTHREAD_COMM_LEN) > > + pr_warn("%s:%d: comm of pid %d is truncated from \"%s\" to \"%s\"\n", > > + __func__, __LINE__, task->pid, namefmt, name); > > + > > set_task_comm(task, name); > > /* > > * root may have changed our (kthreadd's) priority or CPU mask. > > -- > > 2.17.1 > > > > -- > Kees Cook
-- Thanks Yafang
| |