Messages in this thread | | | Date | Thu, 30 Sep 2021 17:17:25 +0200 | From | Petr Mladek <> | Subject | Re: [PATCH 5/5] kernel/kthread: show a warning if kthread's comm is still trucated |
| |
On Wed 2021-09-29 11:50:36, 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> > --- > 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);
The warning makes sense. But the use of "namefmt" looks wrong. It is format and not the name. Also __func__ and __LINE__ is overkill. It will be always the same.
I would do something like:
len = vsnprintf(name, sizeof(name), namefmt, args); if (len >= KTHREAD_COMM_LEN) { pr_warn("truncated kthread comm:%s, pid:%d by %d characters\n", name, task->pid, len - KTHREAD_COMM_LEN + 1); }
Best Regards, Petr
| |