Messages in this thread | | | From | Yafang Shao <> | Date | Fri, 1 Oct 2021 19:59:54 +0800 | Subject | Re: [PATCH 5/5] kernel/kthread: show a warning if kthread's comm is still trucated |
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On Thu, Sep 30, 2021 at 11:17 PM Petr Mladek <pmladek@suse.com> wrote: > > 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); > } >
Thanks for the suggestion. I will change it.
-- Thanks Yafang
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