From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
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>,
Mel Gorman <mgorman@techsingularity.net>,
Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Laura Abbott <labbott@redhat.com>,
Andy Lutomirski <luto@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Kees Cook <keescook@chromium.org>,
linux-kernel@vger.kernel.org,
Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Subject: Re: [RFC][PATCHv4 5/6] printk: use printk_safe buffers
Date: Thu, 1 Dec 2016 11:14:07 +0900 [thread overview]
Message-ID: <20161201021407.GF12039@jagdpanzerIV> (raw)
In-Reply-To: <20161125142855.GI24103@pathway.suse.cz>
On (11/25/16 15:28), Petr Mladek wrote:
[..]
> I really like this patch. The only small problem is that it enables
> lockdep and it does not explain why it is safe. The change itself
> looks fine but it took me some time to prove why. IMHO, it is
> worth a comment.
>
> One thing is printk() recursion caused by lockdep warning
> triggered from inside vprintk_emit(). It is safe because
> the critical sections are guarded by printk_safe_enter()/exit()
> now.
>
> Another thing is lockdep recursion caused by catching another lockdep
> issue when printing warning about the first one. This is safe
> because lockdep protects itself. First, it sets and checks
> current->lockdep_recursion around the critical sections.
> Second, further checks are disabled entirely once first
> lockdep issue is found.
>
> If you add some comments about lockdep, feel free to use:
ok, I'll try to.
-ss
next prev parent reply other threads:[~2016-12-01 2:14 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-27 15:49 [RFC][PATCHv4 0/6] printk: use printk_safe to handle printk() recursive calls Sergey Senozhatsky
2016-10-27 15:49 ` [RFC][PATCHv4 1/6] printk: use vprintk_func in vprintk() Sergey Senozhatsky
2016-11-24 16:28 ` Petr Mladek
2016-10-27 15:49 ` [RFC][PATCHv4 2/6] printk: rename nmi.c and exported api Sergey Senozhatsky
2016-11-24 16:35 ` Petr Mladek
2016-12-01 1:07 ` Sergey Senozhatsky
2016-12-01 12:12 ` Petr Mladek
2016-10-27 15:49 ` [RFC][PATCHv4 3/6] printk: introduce per-cpu safe_print seq buffer Sergey Senozhatsky
2016-11-24 16:58 ` Petr Mladek
2016-12-01 1:08 ` Sergey Senozhatsky
2016-12-01 5:32 ` Sergey Senozhatsky
2016-10-27 15:49 ` [RFC][PATCHv4 4/6] printk: report lost messages in printk safe/nmi contexts Sergey Senozhatsky
2016-11-25 11:07 ` Petr Mladek
2016-12-01 2:10 ` Sergey Senozhatsky
2016-12-01 12:50 ` Petr Mladek
2016-10-27 15:49 ` [RFC][PATCHv4 5/6] printk: use printk_safe buffers Sergey Senozhatsky
2016-11-25 14:28 ` Petr Mladek
2016-12-01 2:14 ` Sergey Senozhatsky [this message]
2016-10-27 15:49 ` [RFC][PATCHv4 6/6] printk: remove zap_locks() function Sergey Senozhatsky
2016-11-25 15:01 ` Petr Mladek
2016-11-25 15:17 ` Peter Zijlstra
2016-12-01 2:34 ` Sergey Senozhatsky
2016-12-01 5:42 ` Peter Zijlstra
2016-12-01 13:36 ` Petr Mladek
2016-12-02 1:11 ` Sergey Senozhatsky
2016-12-01 2:18 ` Sergey Senozhatsky
2016-12-01 12:50 ` Sergey Senozhatsky
2016-12-01 13:15 ` Petr Mladek
2016-10-28 3:30 ` [RFC][PATCHv4 0/6] printk: use printk_safe to handle printk() recursive calls Linus Torvalds
2016-10-28 4:05 ` 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=20161201021407.GF12039@jagdpanzerIV \
--to=sergey.senozhatsky.work@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=calvinowens@fb.com \
--cc=jack@suse.cz \
--cc=keescook@chromium.org \
--cc=labbott@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@kernel.org \
--cc=mgorman@techsingularity.net \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=pmladek@suse.com \
--cc=rostedt@goodmis.org \
--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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.