From: John Ogness <john.ogness@linutronix.de>
To: Sergey Senozhatsky <senozhatsky@chromium.org>,
Stephen Brennan <stephen.s.brennan@oracle.com>
Cc: Petr Mladek <pmladek@suse.com>,
Sergey Senozhatsky <senozhatsky@chromium.org>,
Steven Rostedt <rostedt@goodmis.org>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/4] printk: disable optimistic spin during panic
Date: Wed, 26 Jan 2022 10:51:22 +0106 [thread overview]
Message-ID: <87r18un83x.fsf@jogness.linutronix.de> (raw)
In-Reply-To: <YfER7tlXZZpX94c9@google.com>
> Is there something that prevents panic CPU from NMI hlt CPU which is
> in console_trylock() under raw_spin_lock_irqsave()?
>
> CPU0 CPU1
> console_trylock_spinnning()
> console_trylock()
> down_trylock()
> raw_spin_lock_irqsave(&sem->lock)
>
> panic()
> crash_smp_send_stop()
> NMI -> HALT
This is a good point. I wonder if console_flush_on_panic() should
perform a sema_init() before it does console_trylock().
John
next prev parent reply other threads:[~2022-01-26 9:45 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-21 19:02 [PATCH 0/4] printk: reduce deadlocks during panic Stephen Brennan
2022-01-21 19:02 ` [PATCH 1/4] panic: Add panic_in_progress helper Stephen Brennan
2022-01-25 11:48 ` Petr Mladek
2022-01-26 17:37 ` Stephen Brennan
2022-01-21 19:02 ` [PATCH 2/4] printk: disable optimistic spin during panic Stephen Brennan
2022-01-25 12:42 ` Petr Mladek
2022-01-26 9:18 ` Sergey Senozhatsky
2022-01-26 9:45 ` John Ogness [this message]
2022-01-26 10:06 ` Sergey Senozhatsky
2022-01-26 18:15 ` Stephen Brennan
2022-01-27 7:11 ` Sergey Senozhatsky
2022-01-27 9:09 ` John Ogness
2022-01-27 11:38 ` Petr Mladek
2022-01-27 12:43 ` John Ogness
2022-01-27 14:25 ` Petr Mladek
2022-01-21 19:02 ` [PATCH 3/4] printk: Avoid livelock with heavy printk " Stephen Brennan
2022-01-25 14:25 ` Petr Mladek
2022-01-21 19:02 ` [PATCH 4/4] printk: Drop console_sem " Stephen Brennan
2022-01-24 16:12 ` John Ogness
2022-01-24 16:26 ` John Ogness
2022-01-25 15:04 ` Petr Mladek
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