From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Joe Perches <joe@perches.com>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Petr Mladek <pmladek@suse.cz>, Tejun Heo <tj@kernel.org>,
Calvin Owens <calvinowens@fb.com>,
Steven Rostedt <rostedt@goodmis.org>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: linux.git: printk() problem
Date: Tue, 25 Oct 2016 11:24:36 +0900 [thread overview]
Message-ID: <20161025022436.GB446@swordfish> (raw)
In-Reply-To: <20161025015554.GA495@swordfish>
On (10/25/16 10:55), Sergey Senozhatsky wrote:
> I think cont_flush() should grab the logbuf_lock lock, because
> it does log_store() and touches the cont.len. so something like
> this perhaps
>
> diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
> index c7f490f..47f887c 100644
> --- a/kernel/printk/printk.c
> +++ b/kernel/printk/printk.c
> @@ -1608,13 +1608,20 @@ static struct cont {
>
> static bool cont_flush(void)
> {
> + unsigned long flags;
> + bool flushed = false;
> +
> + raw_spin_lock_irqsave(&logbuf_lock, flags);
> if (!cont.len)
> - return false;
> + goto out;
>
> log_store(cont.facility, cont.level, cont.flags, cont.ts_nsec,
> NULL, 0, cont.buf, cont.len);
> cont.len = 0;
> - return true;
> + flushed = true;
> +out:
> + raw_spin_unlock_irqrestore(&logbuf_lock, flags);
> + return flushed;
> }
... clearly, wasn't tested at all! sorry about that.
what I meant was cont_flush() from deferred_cont_flush()->flush_timer().
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index c7f490f..bd7841c 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -1619,7 +1619,14 @@ static bool cont_flush(void)
static void flush_timer(unsigned long data)
{
- if (cont_flush())
+ unsigned long flags;
+ bool flushed;
+
+ raw_spin_lock_irqsave(&logbuf_lock, flags);
+ flushed = cont_flush();
+ raw_spin_unlock_irqrestore(&logbuf_lock, flags);
+
+ if (flushed)
wake_up_klogd();
}
-ss
next prev parent reply other threads:[~2016-10-25 2:24 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-12 13:30 linux.git: printk() problem Tetsuo Handa
2016-10-12 14:35 ` Michal Hocko
2016-10-12 16:08 ` Joe Perches
2016-10-13 6:26 ` Michal Hocko
2016-10-13 9:29 ` Joe Perches
2016-10-13 10:04 ` Michal Hocko
2016-10-13 10:20 ` Joe Perches
2016-10-13 11:06 ` Michal Hocko
2016-10-12 15:47 ` Linus Torvalds
2016-10-12 16:16 ` Joe Perches
2016-10-12 16:54 ` Linus Torvalds
2016-10-12 18:50 ` [PATCH] acpi_os_vprintf: Use printk_get_level() to avoid unnecessary KERN_CONT Joe Perches
2016-10-13 21:59 ` Rafael J. Wysocki
2016-10-23 9:22 ` linux.git: printk() problem Geert Uytterhoeven
2016-10-23 18:11 ` Linus Torvalds
2016-10-23 19:06 ` Joe Perches
2016-10-23 19:32 ` Linus Torvalds
2016-10-23 19:46 ` Linus Torvalds
2016-10-24 11:15 ` Geert Uytterhoeven
2016-10-24 14:08 ` Sergey Senozhatsky
2016-10-24 14:23 ` Sergey Senozhatsky
2016-10-24 17:54 ` Linus Torvalds
2016-10-24 17:55 ` Linus Torvalds
2016-10-25 1:55 ` Sergey Senozhatsky
2016-10-25 2:06 ` Linus Torvalds
2016-10-25 2:22 ` Linus Torvalds
2016-10-25 4:06 ` Sergey Senozhatsky
2016-10-25 4:13 ` Joe Perches
2016-10-25 4:15 ` Linus Torvalds
2016-10-25 4:44 ` Sergey Senozhatsky
2016-10-25 14:44 ` Petr Mladek
2016-11-09 15:47 ` Petr Mladek
2016-10-25 2:24 ` Sergey Senozhatsky [this message]
2016-10-23 20:33 ` Joe Perches
2016-10-23 21:13 ` Linus Torvalds
2016-10-25 14:42 ` Steven Rostedt
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