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From: "Jason A. Donenfeld" <Jason@zx2c4.com>
To: Dmitry Vyukov <dvyukov@google.com>
Cc: John Ogness <john.ogness@linutronix.de>,
	Geert Uytterhoeven <geert@linux-m68k.org>,
	Marek Szyprowski <m.szyprowski@samsung.com>,
	Petr Mladek <pmladek@suse.com>,
	Sergey Senozhatsky <senozhatsky@chromium.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"open list:ARM/Amlogic Meson..."
	<linux-amlogic@lists.infradead.org>,
	Theodore Ts'o <tytso@mit.edu>,
	Alexander Potapenko <glider@google.com>,
	Marco Elver <elver@google.com>,
	kasan-dev@googlegroups.com, bigeasy@linutronix.de
Subject: Re: [PATCH printk v5 1/1] printk: extend console_lock for per-console locking
Date: Thu, 9 Jun 2022 14:27:11 +0200	[thread overview]
Message-ID: <YqHnH+Yc4TCOXa9X@zx2c4.com> (raw)
In-Reply-To: <CACT4Y+ajfVUkqAjAin73ftqAz=HmLX=p=S=HRV1qe-8_y36J+A@mail.gmail.com>

Hi Dmitry,

On Thu, Jun 09, 2022 at 02:18:19PM +0200, Dmitry Vyukov wrote:
> > AFAIK, CONFIG_PROVE_RAW_LOCK_NESTING is useful for teasing out cases
> > where RT's raw spinlocks will nest wrong with RT's sleeping spinlocks.
> > But nobody who wants an RT kernel will be using KFENCE. So this seems
> > like a non-issue? Maybe just add a `depends on !KFENCE` to
> > PROVE_RAW_LOCK_NESTING?
> 
> Don't know if there are other good solutions (of similar simplicity).

Fortunately, I found one that solves things without needing to
compromise on anything:
https://lore.kernel.org/lkml/20220609121709.12939-1-Jason@zx2c4.com/

> Btw, should this new CONFIG_PROVE_RAW_LOCK_NESTING be generally
> enabled on testing systems? We don't have it enabled on syzbot.

Last time I spoke with RT people about this, the goal was eventually to
*always* enable it when lock proving is enabled, but there are too many
bugs and cases now to do that, so it's an opt-in. I might be
misremembering, though, so CC'ing Sebastian in case he wants to chime
in.

Jason

  reply	other threads:[~2022-06-09 12:27 UTC|newest]

Thread overview: 63+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-21 21:22 [PATCH printk v4 00/15] implement threaded console printing John Ogness
2022-04-21 21:22 ` [PATCH printk v4 01/15] printk: rename cpulock functions John Ogness
2022-04-21 21:22 ` [PATCH printk v4 02/15] printk: cpu sync always disable interrupts John Ogness
2022-04-21 21:22 ` [PATCH printk v4 03/15] printk: add missing memory barrier to wake_up_klogd() John Ogness
2022-04-21 21:22 ` [PATCH printk v4 04/15] printk: wake up all waiters John Ogness
2022-04-21 21:22 ` [PATCH printk v4 05/15] printk: wake waiters for safe and NMI contexts John Ogness
2022-04-21 21:22 ` [PATCH printk v4 06/15] printk: get caller_id/timestamp after migration disable John Ogness
2022-04-21 21:22 ` [PATCH printk v4 07/15] printk: call boot_delay_msec() in printk_delay() John Ogness
2022-04-21 21:22 ` [PATCH printk v4 08/15] printk: add con_printk() macro for console details John Ogness
2022-04-21 21:22 ` [PATCH printk v4 09/15] printk: refactor and rework printing logic John Ogness
2022-04-21 21:22 ` [PATCH printk v4 10/15] printk: move buffer definitions into console_emit_next_record() caller John Ogness
2022-04-21 21:22 ` [PATCH printk v4 11/15] printk: add pr_flush() John Ogness
2022-04-21 21:22 ` [PATCH printk v4 12/15] printk: add functions to prefer direct printing John Ogness
2022-04-21 21:22 ` [PATCH printk v4 13/15] printk: add kthread console printers John Ogness
2022-04-22  7:48   ` Petr Mladek
2022-04-21 21:22 ` [PATCH printk v4 14/15] printk: extend console_lock for proper kthread support John Ogness
2022-04-21 21:40   ` John Ogness
2022-04-22  9:21   ` Petr Mladek
2022-04-25 20:58   ` [PATCH printk v5 1/1] printk: extend console_lock for per-console locking John Ogness
2022-04-26 12:07     ` Petr Mladek
2022-04-26 13:16       ` Petr Mladek
2022-04-27  7:08         ` Marek Szyprowski
2022-04-27  7:38           ` Petr Mladek
2022-04-27 11:44             ` Marek Szyprowski
2022-04-27 16:15               ` John Ogness
2022-04-27 16:48                 ` Petr Mladek
2022-04-28 14:54                 ` Petr Mladek
2022-04-29 13:53                 ` Marek Szyprowski
2022-04-30 16:00                   ` John Ogness
2022-05-02  9:19                     ` Marek Szyprowski
2022-05-02 13:11                       ` John Ogness
2022-05-02 22:29                         ` Marek Szyprowski
2022-05-04  5:56                           ` John Ogness
2022-05-04  6:52                             ` Marek Szyprowski
2022-06-08 15:10                         ` Geert Uytterhoeven
2022-06-09 11:19                           ` John Ogness
2022-06-09 11:58                             ` Jason A. Donenfeld
2022-06-09 12:18                               ` Dmitry Vyukov
2022-06-09 12:27                                 ` Jason A. Donenfeld [this message]
2022-06-09 12:32                                   ` Dmitry Vyukov
2022-06-17 16:51                                   ` Sebastian Andrzej Siewior
2022-06-09 12:18                               ` Jason A. Donenfeld
2022-05-02 13:17                       ` Petr Mladek
2022-05-02 23:13                         ` Marek Szyprowski
2022-05-03  6:49                           ` Petr Mladek
2022-05-04  6:05                             ` Marek Szyprowski
2022-05-04 21:11                           ` John Ogness
2022-05-04 22:42                             ` John Ogness
2022-05-05 22:33                               ` John Ogness
2022-05-06  6:43                                 ` Marek Szyprowski
2022-05-06  7:55                                   ` Neil Armstrong
2022-05-08 11:02                                     ` John Ogness
2022-05-06  8:16                                   ` Petr Mladek
2022-05-06  9:20                                   ` John Ogness
2022-05-06 11:25           ` Marek Szyprowski
2022-05-06 12:41             ` John Ogness
2022-05-06 13:04               ` Marek Szyprowski
2022-06-22  9:03     ` Geert Uytterhoeven
2022-06-22 22:37       ` John Ogness
2022-06-23 10:10         ` Geert Uytterhoeven
2022-04-21 21:22 ` [PATCH printk v4 15/15] printk: remove @console_locked John Ogness
2022-04-22  9:39 ` [PATCH printk v4 00/15] implement threaded console printing Petr Mladek
2022-04-22 20:29   ` Petr Mladek

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