From: John Ogness <john.ogness@linutronix.de>
To: Petr Mladek <pmladek@suse.com>
Cc: "Sergey Senozhatsky" <sergey.senozhatsky.work@gmail.com>,
"Sergey Senozhatsky" <sergey.senozhatsky@gmail.com>,
"Steven Rostedt" <rostedt@goodmis.org>,
"Thomas Gleixner" <tglx@linutronix.de>,
linux-kernel@vger.kernel.org,
"Michael Ellerman" <mpe@ellerman.id.au>,
"Benjamin Herrenschmidt" <benh@kernel.crashing.org>,
"Paul Mackerras" <paulus@samba.org>,
"Eric Biederman" <ebiederm@xmission.com>,
"Nicholas Piggin" <npiggin@gmail.com>,
"Christophe Leroy" <christophe.leroy@csgroup.eu>,
"Alistair Popple" <alistair@popple.id.au>,
"Jordan Niethe" <jniethe5@gmail.com>,
"Peter Zijlstra" <peterz@infradead.org>,
"Cédric Le Goater" <clg@kaod.org>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Kees Cook" <keescook@chromium.org>, "Yue Hu" <huyue2@yulong.com>,
"Alexey Kardashevskiy" <aik@ozlabs.ru>,
"Rafael Aquini" <aquini@redhat.com>,
"Tiezhu Yang" <yangtiezhu@loongson.cn>,
"Guilherme G. Piccoli" <gpiccoli@canonical.com>,
"Paul E. McKenney" <paulmck@kernel.org>,
linuxppc-dev@lists.ozlabs.org, kexec@lists.infradead.org
Subject: Re: [PATCH next v1 2/3] printk: remove safe buffers
Date: Mon, 29 Mar 2021 17:10:02 +0200 [thread overview]
Message-ID: <87sg4e6lo5.fsf@jogness.linutronix.de> (raw)
In-Reply-To: <YGGmNu5ilDnSKH3g@alley>
On 2021-03-29, Petr Mladek <pmladek@suse.com> wrote:
> I wonder if some console drivers rely on the fact that the write()
> callback is called with interrupts disabled.
>
> IMHO, it would be a bug when any write() callback expects that
> callers disabled the interrupts.
Agreed.
> Do you plan to remove the console-spinning stuff after offloading
> consoles to the kthreads?
Yes. Although a similar concept will be introduced to allow the threaded
printers and the atomic consoles to compete.
> Will you call console write() callback with irq enabled from the
> kthread?
No. That defeats the fundamental purpose of this entire rework
excercise. ;-)
> Anyway, we should at least add a comment why the interrupts are
> disabled.
I decided to move the local_irq_save/restore inside the console-spinning
functions and added a comment for v2.
John Ogness
WARNING: multiple messages have this Message-ID (diff)
From: John Ogness <john.ogness@linutronix.de>
To: Petr Mladek <pmladek@suse.com>
Cc: "Sergey Senozhatsky" <sergey.senozhatsky.work@gmail.com>,
"Peter Zijlstra" <peterz@infradead.org>,
"Paul Mackerras" <paulus@samba.org>,
"Tiezhu Yang" <yangtiezhu@loongson.cn>,
"Rafael Aquini" <aquini@redhat.com>,
"Alexey Kardashevskiy" <aik@ozlabs.ru>,
"Yue Hu" <huyue2@yulong.com>,
"Jordan Niethe" <jniethe5@gmail.com>,
"Kees Cook" <keescook@chromium.org>,
"Paul E. McKenney" <paulmck@kernel.org>,
"Alistair Popple" <alistair@popple.id.au>,
"Guilherme G. Piccoli" <gpiccoli@canonical.com>,
"Nicholas Piggin" <npiggin@gmail.com>,
"Steven Rostedt" <rostedt@goodmis.org>,
"Thomas Gleixner" <tglx@linutronix.de>,
kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
"Sergey Senozhatsky" <sergey.senozhatsky@gmail.com>,
"Eric Biederman" <ebiederm@xmission.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
linuxppc-dev@lists.ozlabs.org, "Cédric Le Goater" <clg@kaod.org>
Subject: Re: [PATCH next v1 2/3] printk: remove safe buffers
Date: Mon, 29 Mar 2021 17:10:02 +0200 [thread overview]
Message-ID: <87sg4e6lo5.fsf@jogness.linutronix.de> (raw)
In-Reply-To: <YGGmNu5ilDnSKH3g@alley>
On 2021-03-29, Petr Mladek <pmladek@suse.com> wrote:
> I wonder if some console drivers rely on the fact that the write()
> callback is called with interrupts disabled.
>
> IMHO, it would be a bug when any write() callback expects that
> callers disabled the interrupts.
Agreed.
> Do you plan to remove the console-spinning stuff after offloading
> consoles to the kthreads?
Yes. Although a similar concept will be introduced to allow the threaded
printers and the atomic consoles to compete.
> Will you call console write() callback with irq enabled from the
> kthread?
No. That defeats the fundamental purpose of this entire rework
excercise. ;-)
> Anyway, we should at least add a comment why the interrupts are
> disabled.
I decided to move the local_irq_save/restore inside the console-spinning
functions and added a comment for v2.
John Ogness
WARNING: multiple messages have this Message-ID (diff)
From: John Ogness <john.ogness@linutronix.de>
To: Petr Mladek <pmladek@suse.com>
Cc: "Sergey Senozhatsky" <sergey.senozhatsky.work@gmail.com>,
"Sergey Senozhatsky" <sergey.senozhatsky@gmail.com>,
"Steven Rostedt" <rostedt@goodmis.org>,
"Thomas Gleixner" <tglx@linutronix.de>,
linux-kernel@vger.kernel.org,
"Michael Ellerman" <mpe@ellerman.id.au>,
"Benjamin Herrenschmidt" <benh@kernel.crashing.org>,
"Paul Mackerras" <paulus@samba.org>,
"Eric Biederman" <ebiederm@xmission.com>,
"Nicholas Piggin" <npiggin@gmail.com>,
"Christophe Leroy" <christophe.leroy@csgroup.eu>,
"Alistair Popple" <alistair@popple.id.au>,
"Jordan Niethe" <jniethe5@gmail.com>,
"Peter Zijlstra" <peterz@infradead.org>,
"Cédric Le Goater" <clg@kaod.org>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Kees Cook" <keescook@chromium.org>, "Yue Hu" <huyue2@yulong.com>,
"Alexey Kardashevskiy" <aik@ozlabs.ru>,
"Rafael Aquini" <aquini@redhat.com>,
"Tiezhu Yang" <yangtiezhu@loongson.cn>,
"Guilherme G. Piccoli" <gpiccoli@canonical.com>,
"Paul E. McKenney" <paulmck@kernel.org>,
linuxppc-dev@lists.ozlabs.org, kexec@lists.infradead.org
Subject: Re: [PATCH next v1 2/3] printk: remove safe buffers
Date: Mon, 29 Mar 2021 17:10:02 +0200 [thread overview]
Message-ID: <87sg4e6lo5.fsf@jogness.linutronix.de> (raw)
In-Reply-To: <YGGmNu5ilDnSKH3g@alley>
On 2021-03-29, Petr Mladek <pmladek@suse.com> wrote:
> I wonder if some console drivers rely on the fact that the write()
> callback is called with interrupts disabled.
>
> IMHO, it would be a bug when any write() callback expects that
> callers disabled the interrupts.
Agreed.
> Do you plan to remove the console-spinning stuff after offloading
> consoles to the kthreads?
Yes. Although a similar concept will be introduced to allow the threaded
printers and the atomic consoles to compete.
> Will you call console write() callback with irq enabled from the
> kthread?
No. That defeats the fundamental purpose of this entire rework
excercise. ;-)
> Anyway, we should at least add a comment why the interrupts are
> disabled.
I decided to move the local_irq_save/restore inside the console-spinning
functions and added a comment for v2.
John Ogness
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kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
next prev parent reply other threads:[~2021-03-29 15:10 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-16 23:33 [PATCH next v1 0/3] printk: remove safe buffers John Ogness
2021-03-16 23:33 ` John Ogness
2021-03-16 23:33 ` John Ogness
2021-03-16 23:33 ` [PATCH next v1 1/3] printk: track/limit recursion John Ogness
2021-03-21 5:34 ` Sergey Senozhatsky
2021-03-22 10:53 ` John Ogness
2021-03-22 11:13 ` Sergey Senozhatsky
2021-03-22 15:07 ` Petr Mladek
2021-03-22 14:49 ` Petr Mladek
2021-03-23 21:32 ` John Ogness
2021-03-24 8:41 ` Petr Mladek
2021-03-16 23:33 ` [PATCH next v1 2/3] printk: remove safe buffers John Ogness
2021-03-16 23:33 ` John Ogness
2021-03-16 23:33 ` John Ogness
2021-03-21 5:26 ` Sergey Senozhatsky
2021-03-21 5:26 ` Sergey Senozhatsky
2021-03-21 5:26 ` Sergey Senozhatsky
2021-03-22 11:16 ` John Ogness
2021-03-22 11:16 ` John Ogness
2021-03-22 11:16 ` John Ogness
2021-03-22 18:02 ` Petr Mladek
2021-03-22 18:02 ` Petr Mladek
2021-03-22 18:02 ` Petr Mladek
2021-03-22 21:58 ` John Ogness
2021-03-22 21:58 ` John Ogness
2021-03-22 21:58 ` John Ogness
2021-03-23 9:46 ` Petr Mladek
2021-03-23 9:46 ` Petr Mladek
2021-03-23 9:46 ` Petr Mladek
2021-03-23 10:47 ` Petr Mladek
2021-03-23 10:47 ` Petr Mladek
2021-03-23 10:47 ` Petr Mladek
2021-03-26 11:12 ` John Ogness
2021-03-26 11:12 ` John Ogness
2021-03-26 11:12 ` John Ogness
2021-03-29 10:04 ` Petr Mladek
2021-03-29 10:04 ` Petr Mladek
2021-03-29 10:04 ` Petr Mladek
2021-03-29 15:10 ` John Ogness [this message]
2021-03-29 15:10 ` John Ogness
2021-03-29 15:10 ` John Ogness
2021-03-29 15:13 ` John Ogness
2021-03-29 15:13 ` John Ogness
2021-03-29 15:13 ` John Ogness
2021-03-16 23:33 ` [PATCH next v1 3/3] printk: convert @syslog_lock to spin_lock John Ogness
2021-03-23 12:01 ` Petr Mladek
2021-03-26 11:23 ` John Ogness
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