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From: Jiri Slaby <jslaby@suse.cz>
To: Arseny Maslennikov <ar@cs.msu.ru>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Rob Landley <rob@landley.net>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	Pavel Machek <pavel@ucw.cz>,
	linux-api@vger.kernel.org,
	"Vladimir D. Seleznev" <vseleznv@altlinux.org>
Subject: Re: [PATCH v3 4/7] linux/signal.h: Ignore SIGINFO by default in new tasks
Date: Thu, 30 Apr 2020 08:53:56 +0200	[thread overview]
Message-ID: <780cb05e-a749-77a0-dabc-bd09982aa028@suse.cz> (raw)
In-Reply-To: <20200430064301.1099452-5-ar@cs.msu.ru>

On 30. 04. 20, 8:42, Arseny Maslennikov wrote:
> This matches the behaviour of other Unix-like systems that have SIGINFO
> and causes less harm to processes that do not install handlers for this
> signal, making the keyboard status character non-fatal for them.
> 
> This is implemented with the assumption that SIGINFO is defined
> to be equivalent to SIGPWR; still, there is no reason for PWR to
> result in termination of the signal recipient anyway — it does not
> indicate there is a fatal problem with the recipient's execution
> context (like e.g. FPE/ILL do), and we have TERM/KILL for explicit
> termination requests.
> 
> To put it another way:
> The only scenario where system behaviour actually changes is when the
> signal recipient has default disposition for SIGPWR. If a process
> chose to interpret a SIGPWR as an incentive to cleanly terminate, it
> would supply its own handler — and this commit does not affect processes
> with non-default handlers.
> 
> Signed-off-by: Arseny Maslennikov <ar@cs.msu.ru>
> ---
>  include/linux/signal.h | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/include/linux/signal.h b/include/linux/signal.h
> index 05bacd2ab..dc31da8fc 100644
> --- a/include/linux/signal.h
> +++ b/include/linux/signal.h
> @@ -369,7 +369,7 @@ extern bool unhandled_signal(struct task_struct *tsk, int sig);
>   *	|  SIGSYS/SIGUNUSED  |	coredump 	|
>   *	|  SIGSTKFLT         |	terminate	|
>   *	|  SIGWINCH          |	ignore   	|
> - *	|  SIGPWR            |	terminate	|
> + *	|  SIGPWR            |	ignore   	|

You need to update signal.7 too:
https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/man7/signal.7#n285

thanks,
-- 
js
suse labs

  reply	other threads:[~2020-04-30  6:54 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-30  6:42 [PATCH v3 0/7] TTY Keyboard Status Request Arseny Maslennikov
2020-04-30  6:42 ` [PATCH v3 1/7] signal.h: Define SIGINFO on all architectures Arseny Maslennikov
2020-04-30  6:42 ` [PATCH v3 2/7] tty: termios: Reserve space for VSTATUS in .c_cc Arseny Maslennikov
2020-04-30  6:42 ` [PATCH v3 3/7] n_tty: Send SIGINFO to fg pgrp on status request character Arseny Maslennikov
2020-04-30  6:42 ` [PATCH v3 4/7] linux/signal.h: Ignore SIGINFO by default in new tasks Arseny Maslennikov
2020-04-30  6:53   ` Jiri Slaby [this message]
2020-04-30  7:14     ` Christian Brauner
2020-04-30  7:19       ` Greg Kroah-Hartman
2020-04-30  7:37       ` Aleksa Sarai
2020-04-30  8:00         ` Christian Brauner
2020-04-30  6:42 ` [PATCH v3 5/7] tty: Add NOKERNINFO lflag to termios Arseny Maslennikov
2020-04-30  6:55   ` Jiri Slaby
2020-04-30  7:20     ` Arseny Maslennikov
2020-04-30  6:43 ` [PATCH v3 6/7] n_tty: ->ops->write: Cut core logic out to a separate function Arseny Maslennikov
2020-04-30  6:43 ` [PATCH v3 7/7] n_tty: Provide an informational line on VSTATUS receipt Arseny Maslennikov
2020-04-30  7:29   ` Jiri Slaby
2020-04-30  9:08     ` Arseny Maslennikov

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