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From: Oleg Nesterov <oleg@redhat.com>
To: Mandeep Singh Baines <msb@chromium.org>
Cc: linux-kernel@vger.kernel.org, Tejun Heo <tj@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	"Rafael J. Wysocki" <rjw@sisk.pl>, Ingo Molnar <mingo@redhat.com>
Subject: Re: [PATCH 2/5] lockdep: check that no locks held at freeze time
Date: Fri, 15 Feb 2013 16:44:49 +0100	[thread overview]
Message-ID: <20130215154449.GD30829@redhat.com> (raw)
In-Reply-To: <1360885096-21207-2-git-send-email-msb@chromium.org>

On 02/14, Mandeep Singh Baines wrote:
>
> We shouldn't try_to_freeze if locks are held. Verified that
> I get no lockdep warnings after applying this patch and
> "vfork: don't freezer_count() for in-kernel users of CLONE_VFORK".

Ah. Now I understand why you did 1/5. Beacuse you call
debug_check_no_locks_held() right at the start of try_to_freeze(),
even if the caller can't be frozen.

>  static inline bool try_to_freeze(void)
>  {
> +	debug_check_no_locks_held(current);
>  	might_sleep();
>  	if (likely(!freezing(current)))
>  		return false;

Up to maintainers, but perhaps you should check !PF_NOFREEZE at least?

Oleg.


  parent reply	other threads:[~2013-02-15 15:46 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-02-14 23:38 [PATCH 1/5] vfork: don't freezer_count() for in-kernel users of CLONE_VFORK Mandeep Singh Baines
2013-02-14 23:38 ` [PATCH 2/5] lockdep: check that no locks held at freeze time Mandeep Singh Baines
2013-02-15 11:16   ` Ingo Molnar
2013-02-15 15:44   ` Oleg Nesterov [this message]
2013-02-14 23:38 ` [PATCH 3/5] coredump: cleanup the waiting for coredump_finish code Mandeep Singh Baines
2013-02-15 14:53   ` Oleg Nesterov
2013-02-15 23:30   ` Andrew Morton
2013-02-14 23:38 ` [PATCH 4/5] coredump: use a freezable_schedule for the coredump_finish wait Mandeep Singh Baines
2013-02-14 23:38 ` [PATCH 5/5] coredump: abort core dump piping only due to a fatal signal Mandeep Singh Baines
2013-02-15 15:01   ` Oleg Nesterov
2013-02-16  1:20     ` Mandeep Singh Baines
2013-02-16 17:05       ` Oleg Nesterov
2013-02-15 23:25   ` Andrew Morton
2013-02-16  0:09   ` [PATCH v3] coredump: ignore non-fatal signals when core dumping to a pipe Mandeep Singh Baines
2013-02-16  0:57     ` [PATCH v4] " Mandeep Singh Baines
2013-02-15 15:28 ` [PATCH 1/5] vfork: don't freezer_count() for in-kernel users of CLONE_VFORK Oleg Nesterov
  -- strict thread matches above, loose matches on Subject: below --
2013-02-16  9:53 Mandeep Singh Baines
2013-02-16  9:53 ` [PATCH 2/5] lockdep: check that no locks held at freeze time Mandeep Singh Baines
2013-02-16 17:06   ` Oleg Nesterov

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