From: Petr Mladek <pmladek@suse.com>
To: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Jan Kara <jack@suse.cz>, Tejun Heo <tj@kernel.org>,
Calvin Owens <calvinowens@fb.com>,
Thomas Gleixner <tglx@linutronix.de>,
Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Andy Lutomirski <luto@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
linux-kernel@vger.kernel.org,
Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Subject: Re: [RFC][PATCHv5 6/7] printk: use printk_safe buffers in printk
Date: Mon, 12 Dec 2016 17:30:18 +0100 [thread overview]
Message-ID: <20161212163018.GE2441@pathway.suse.cz> (raw)
In-Reply-To: <20161201135546.15549-7-sergey.senozhatsky@gmail.com>
On Thu 2016-12-01 22:55:45, Sergey Senozhatsky wrote:
> Use printk_safe per-CPU buffers in printk recursion-prone blocks:
> -- around logbuf_lock protected sections in vprintk_emit() and
> console_unlock()
> -- around down_trylock_console_sem() and up_console_sem()
>
> Note that this solution addresses deadlocks caused by printk()
> recursive calls only. That is vprintk_emit() and console_unlock().
>
> Another thing to note is that we now keep lockdep enabled in printk,
> because we are protected against the printk recursion caused by lockdep
> in vprintk_emit() by the printk-safe mechanism - we first switch to
> per-CPU buffers and only then access the deadlock-prone locks.
>
> Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Looks fine and safe to me.
Reviewed-by: Petr Mladek <pmladek@suse.com>
Best Regards,
Petr
next prev parent reply other threads:[~2016-12-12 16:30 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-01 13:55 [RFC][PATCHv5 0/7] printk: use printk_safe to handle printk() recursive calls Sergey Senozhatsky
2016-12-01 13:55 ` [RFC][PATCHv5 1/7] printk: use vprintk_func in vprintk() Sergey Senozhatsky
2016-12-01 13:55 ` [RFC][PATCHv5 2/7] printk: rename nmi.c and exported api Sergey Senozhatsky
2016-12-01 13:55 ` [RFC][PATCHv5 3/7] printk: introduce per-cpu safe_print seq buffer Sergey Senozhatsky
2016-12-09 16:46 ` Petr Mladek
2016-12-10 3:10 ` Sergey Senozhatsky
2016-12-12 13:54 ` Petr Mladek
2016-12-12 14:12 ` Sergey Senozhatsky
2016-12-12 15:15 ` Petr Mladek
2016-12-12 15:28 ` Sergey Senozhatsky
2016-12-01 13:55 ` [RFC][PATCHv5 4/7] printk: always use deferred printk when flush printk_safe lines Sergey Senozhatsky
2016-12-12 15:20 ` Petr Mladek
2016-12-01 13:55 ` [RFC][PATCHv5 5/7] printk: report lost messages in printk safe/nmi contexts Sergey Senozhatsky
2016-12-12 15:58 ` Petr Mladek
2016-12-13 1:52 ` Sergey Senozhatsky
2016-12-14 10:51 ` Petr Mladek
2016-12-01 13:55 ` [RFC][PATCHv5 6/7] printk: use printk_safe buffers in printk Sergey Senozhatsky
2016-12-12 16:30 ` Petr Mladek [this message]
2016-12-13 1:27 ` Sergey Senozhatsky
2016-12-01 13:55 ` [RFC][PATCHv5 7/7] printk: remove zap_locks() function Sergey Senozhatsky
2016-12-12 16:37 ` Petr Mladek
2016-12-13 1:26 ` Sergey Senozhatsky
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20161212163018.GE2441@pathway.suse.cz \
--to=pmladek@suse.com \
--cc=akpm@linux-foundation.org \
--cc=calvinowens@fb.com \
--cc=jack@suse.cz \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@kernel.org \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=rostedt@goodmis.org \
--cc=sergey.senozhatsky.work@gmail.com \
--cc=sergey.senozhatsky@gmail.com \
--cc=tglx@linutronix.de \
--cc=tj@kernel.org \
--cc=torvalds@linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox