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References: <cover.1629454773.git.rickyman7@gmail.com> <9dee672538967a3cf7e82ef194ebccc709b1af41.1629454773.git.rickyman7@gmail.com>
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From:   Namhyung Kim <namhyung@kernel.org>
Date:   Tue, 24 Aug 2021 12:27:13 -0700
Message-ID: <CAM9d7cjJuLdBtN_2it88v4VAmVZ5sSzcpDX-eU9A+hiyO3izaA@mail.gmail.com>
Subject: Re: [RFC PATCH v3 06/15] perf workqueue: introduce workqueue struct
To:     Riccardo Mancini <rickyman7@gmail.com>
Cc:     Arnaldo Carvalho de Melo <acme@kernel.org>,
        Ian Rogers <irogers@google.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Jiri Olsa <jolsa@redhat.com>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        linux-perf-users <linux-perf-users@vger.kernel.org>,
        Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com>
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Hi Riccardo,

On Fri, Aug 20, 2021 at 3:54 AM Riccardo Mancini <rickyman7@gmail.com> wrote:
> +/**
> + * workqueue_strerror - print message regarding lastest error in @wq
> + *
> + * Buffer size should be at least WORKQUEUE_STRERR_BUFSIZE bytes.
> + */
> +int workqueue_strerror(struct workqueue_struct *wq, int err, char *buf, size_t size)
> +{
> +       int ret;
> +       char sbuf[THREADPOOL_STRERR_BUFSIZE], *emsg;
> +       const char *errno_str;
> +
> +       errno_str = workqueue_errno_str[-err-WORKQUEUE_ERROR__OFFSET];

It seems easy to crash with an invalid err argument.

> +
> +       switch (err) {
> +       case -WORKQUEUE_ERROR__POOLNEW:
> +       case -WORKQUEUE_ERROR__POOLEXE:
> +       case -WORKQUEUE_ERROR__POOLSTOP:
> +       case -WORKQUEUE_ERROR__POOLSTARTTHREAD:
> +               if (IS_ERR_OR_NULL(wq))
> +                       return scnprintf(buf, size, "%s: unknown.\n",
> +                               errno_str);
> +
> +               ret = threadpool__strerror(wq->pool, wq->pool_errno, sbuf, sizeof(sbuf));
> +               if (ret < 0)
> +                       return ret;
> +               return scnprintf(buf, size, "%s: %s.\n", errno_str, sbuf);
> +       case -WORKQUEUE_ERROR__WRITEPIPE:
> +       case -WORKQUEUE_ERROR__READPIPE:
> +               emsg = str_error_r(errno, sbuf, sizeof(sbuf));

This means the errno should be kept before calling this, right?

> +               return scnprintf(buf, size, "%s: %s.\n", errno_str, emsg);
> +       case -WORKQUEUE_ERROR__INVALIDMSG:
> +               return scnprintf(buf, size, "%s.\n", errno_str);
> +       default:
> +               emsg = str_error_r(err, sbuf, sizeof(sbuf));
> +               return scnprintf(buf, size, "Error: %s", emsg);

Newline at the end?

Thanks,
Namhyung


> +       }
> +}
> +