From: Peter Hurley <peter@hurleysoftware.com>
To: Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Jiri Slaby <jslaby@suse.cz>,
One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>,
linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH 13/26] locking: Add non-fatal spin lock assert
Date: Wed, 10 Sep 2014 10:45:33 -0400 [thread overview]
Message-ID: <5410640D.8010903@hurleysoftware.com> (raw)
In-Reply-To: <20140910130832.GY4783@worktop.ger.corp.intel.com>
On 09/10/2014 09:08 AM, Peter Zijlstra wrote:
> On Wed, Sep 10, 2014 at 07:02:10AM -0400, Peter Hurley wrote:
>> On 09/04/2014 01:14 AM, Ingo Molnar wrote:
>>>
>>> * Peter Zijlstra <peterz@infradead.org> wrote:
>>>
>>>> On Wed, Sep 03, 2014 at 10:50:01AM -0400, Peter Hurley wrote:
>>>>> So a lockdep-only assert is unlikely to draw attention to existing bugs,
>>>>> especially in established drivers.
>>>>
>>>> By the same logic lockdep will not find locking errors in established
>>>> drivers.
>>>
>>> Indeed, this patch is ill-advised in several ways:
>>>
>>> - it extends an API variant that we want to phase
>>>
>>> - emits a warning even if say lockdep has already emitted a
>>> warning and locking state is not guaranteed to be consistent.
>>>
>>> - makes the kernel more expensive once fully debugged, in that
>>> non-fatal checks are unconditional.
>>
>> Ok.
>>
>> One thing: I'm not seeing how lockdep_assert_held() switches off once
>> the warning has been emitted? Is the caller expected to construct their
>> own _ONCE tags?
>
> Indeed, it does not do that. I suppose you can add
> lockdep_assert_held_once() or somesuch if you think the once thing is
> important.
Ok, will do.
On 09/04/2014 01:14 AM, Ingo Molnar wrote:
> Also please submit locking related patches as standalone series
> to the locking subsystem, not embedded in an unrelated series.
Ok, but how will Greg know when to take the series that depends on
this change, if the locking change is submitted separately?
Regards,
Peter Hurley
next prev parent reply other threads:[~2014-09-10 14:45 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-02 21:39 [PATCH 00/26] tty/serial flow control fixes Peter Hurley
2014-09-02 21:39 ` [PATCH 01/26] Revert "serial: uart: add hw flow control support configuration" Peter Hurley
2014-09-02 21:50 ` Murali Karicheri
2014-09-02 21:58 ` Peter Hurley
2014-09-02 22:17 ` Murali Karicheri
2014-09-02 21:39 ` [PATCH 02/26] serial: Style fix Peter Hurley
2014-09-02 21:39 ` [PATCH 03/26] serial: imx: Fix x_char handling and tx flow control Peter Hurley
2014-09-02 21:39 ` [PATCH 04/26] serial: core: Fix x_char race Peter Hurley
2014-09-02 21:39 ` [PATCH 05/26] serial: core: Remove unsafe x_char optimization Peter Hurley
2014-09-02 21:39 ` [PATCH 06/26] serial: Fix send_xchar() handlers Peter Hurley
2014-09-02 21:39 ` [PATCH 07/26] serial: mpc52xx: Use default serial core x_char handler Peter Hurley
2014-09-02 21:39 ` [PATCH 08/26] serial: sunsab: Don't enable tx if tx stopped Peter Hurley
2014-09-02 21:39 ` [PATCH 09/26] serial: blackfin: Fix missing gpio.h Peter Hurley
2014-09-02 21:39 ` [PATCH 10/26] serial: core: Document lock requirement for UPF_* flags updates Peter Hurley
2014-09-02 21:39 ` [PATCH 11/26] serial: 8250: Document serial8250_modem_status() locking Peter Hurley
2014-09-02 21:39 ` [PATCH 12/26] serial: core: Unwrap tertiary assignment in uart_handle_dcd_change() Peter Hurley
2014-09-02 21:39 ` [PATCH 13/26] locking: Add non-fatal spin lock assert Peter Hurley
2014-09-03 9:27 ` Peter Zijlstra
2014-09-03 11:20 ` Peter Hurley
2014-09-03 14:40 ` Peter Zijlstra
2014-09-03 14:50 ` Peter Hurley
2014-09-03 15:07 ` Peter Zijlstra
2014-09-04 5:14 ` Ingo Molnar
2014-09-10 11:02 ` Peter Hurley
2014-09-10 13:08 ` Peter Zijlstra
2014-09-10 14:45 ` Peter Hurley [this message]
2014-09-10 18:34 ` Greg Kroah-Hartman
2014-09-02 21:39 ` [PATCH 14/26] serial: core: Document and assert lock requirements for irq helpers Peter Hurley
2014-09-02 21:39 ` [PATCH 15/26] serial: core: Privatize modem status enable flags Peter Hurley
2014-09-02 21:39 ` [PATCH 16/26] isdn: i4l: Remove ASYNC_CTS_FLOW Peter Hurley
2014-09-02 21:39 ` [PATCH 17/26] serial: core: Privatize tty->hw_stopped Peter Hurley
2014-09-09 0:29 ` Peter Hurley
2014-09-02 21:39 ` [PATCH 18/26] usb: serial: Remove unused tty->hw_stopped Peter Hurley
2014-09-02 21:39 ` [PATCH 19/26] serial: bfin-uart: Fix auto CTS Peter Hurley
2014-09-02 21:39 ` [PATCH 20/26] serial: core: Use spin_lock_irq() in uart_set_termios() Peter Hurley
2014-09-02 21:39 ` [PATCH 21/26] tty: Convert tty_struct bitfield to bools Peter Hurley
2014-09-03 10:58 ` One Thousand Gnomes
2014-09-03 12:14 ` Peter Hurley
2014-09-03 12:19 ` One Thousand Gnomes
2014-09-03 15:10 ` Peter Hurley
2014-09-03 17:56 ` Greg Kroah-Hartman
2014-09-04 16:08 ` Peter Hurley
2014-09-02 21:39 ` [PATCH 22/26] tty: Serialize tty flow control changes with flow_lock Peter Hurley
2014-09-02 21:39 ` [PATCH 23/26] tty: Move packet mode flow control notifications to pty driver Peter Hurley
2014-09-02 21:39 ` [PATCH 24/26] tty: Serialize tcflow() with other tty flow control changes Peter Hurley
2014-09-02 21:39 ` [PATCH 25/26] tty: Move and rename send_prio_char() as tty_send_xchar() Peter Hurley
2014-09-02 21:39 ` [PATCH 26/26] tty: Hold termios_rwsem for tcflow(TCIxxx) Peter Hurley
2014-09-08 23:24 ` [PATCH 00/26] tty/serial flow control fixes Greg Kroah-Hartman
2014-09-08 23:33 ` Peter Hurley
2014-09-08 23:43 ` Greg Kroah-Hartman
2014-09-08 23:46 ` Peter Hurley
2014-09-09 0:01 ` Greg Kroah-Hartman
2014-09-10 19:06 ` [PATCH v2 00/14] " Peter Hurley
2014-09-10 19:06 ` [PATCH v2 01/14] serial: core: Document and assert lock requirements for irq helpers Peter Hurley
2014-09-10 19:06 ` [PATCH v2 02/14] serial: core: Privatize modem status enable flags Peter Hurley
2014-09-10 19:06 ` [PATCH v2 03/14] isdn: i4l: Remove ASYNC_CTS_FLOW Peter Hurley
2014-09-10 19:06 ` [PATCH v2 04/14] serial: core: Privatize tty->hw_stopped Peter Hurley
2014-09-10 19:06 ` [PATCH v2 05/14] usb: serial: Remove unused tty->hw_stopped Peter Hurley
2014-09-23 15:33 ` Johan Hovold
2014-09-10 19:06 ` [PATCH v2 06/14] serial: bfin-uart: Fix auto CTS Peter Hurley
2014-09-10 19:06 ` [PATCH v2 07/14] serial: core: Use spin_lock_irq() in uart_set_termios() Peter Hurley
2014-09-10 19:06 ` [PATCH v2 08/14] tty: Convert tty_struct bitfield to ints Peter Hurley
2014-09-10 19:06 ` [PATCH v2 09/14] tty: Serialize tty flow control changes with flow_lock Peter Hurley
2014-09-10 19:06 ` [PATCH v2 10/14] tty: Move packet mode flow control notifications to pty driver Peter Hurley
2014-09-10 19:06 ` [PATCH v2 11/14] tty: Serialize tcflow() with other tty flow control changes Peter Hurley
2014-09-10 19:06 ` [PATCH v2 12/14] tty: Move and rename send_prio_char() as tty_send_xchar() Peter Hurley
2014-09-10 19:06 ` [PATCH v2 13/14] tty: Hold termios_rwsem for tcflow(TCIxxx) Peter Hurley
2014-09-10 19:06 ` [PATCH v2 14/14] tty: Workaround Alpha non-atomic byte storage in tty_struct Peter Hurley
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