From: Kees Cook <keescook@chromium.org>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>,
Oleg Nesterov <oleg@redhat.com>,
Al Viro <viro@zeniv.linux.org.uk>,
Heiko Carstens <hca@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
linux-s390@vger.kernel.org
Subject: Re: [PATCH 11/20] signal/s390: Use force_sigsegv in default_trap_handler
Date: Thu, 21 Oct 2021 09:17:41 -0700 [thread overview]
Message-ID: <202110210917.FEED0F8@keescook> (raw)
In-Reply-To: <20211020174406.17889-11-ebiederm@xmission.com>
On Wed, Oct 20, 2021 at 12:43:57PM -0500, Eric W. Biederman wrote:
> Reading the history it is unclear why default_trap_handler calls
> do_exit. It is not even menthioned in the commit where the change
> happened. My best guess is that because it is unknown why the
> exception happened it was desired to guarantee the process never
> returned to userspace.
>
> Using do_exit(SIGSEGV) has the problem that it will only terminate one
> thread of a process, leaving the process in an undefined state.
>
> Use force_sigsegv(SIGSEGV) instead which effectively has the same
> behavior except that is uses the ordinary signal mechanism and
> terminates all threads of a process and is generally well defined.
>
> Cc: Heiko Carstens <hca@linux.ibm.com>
> Cc: Vasily Gorbik <gor@linux.ibm.com>
> Cc: Christian Borntraeger <borntraeger@de.ibm.com>
> Cc: linux-s390@vger.kernel.org
> Fixes: ca2ab03237ec ("[PATCH] s390: core changes")
> History Tree: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git
> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
--
Kees Cook
next prev parent reply other threads:[~2021-10-21 16:17 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-20 17:32 [PATCH 00/20] exit cleanups Eric W. Biederman
2021-10-20 17:43 ` [PATCH 02/20] exit: Remove calls of do_exit after noreturn versions of die Eric W. Biederman
2021-10-21 16:02 ` Kees Cook
2021-10-21 16:25 ` Eric W. Biederman
2021-10-20 17:43 ` [PATCH 11/20] signal/s390: Use force_sigsegv in default_trap_handler Eric W. Biederman
2021-10-21 16:17 ` Kees Cook [this message]
2021-10-26 9:38 ` Christian Borntraeger
2021-10-28 15:56 ` Eric W. Biederman
2021-10-29 19:32 ` Eric W. Biederman
2021-10-20 21:51 ` [PATCH 21/20] signal: Replace force_sigsegv(SIGSEGV) with force_fatal_sig(SIGSEGV) Eric W. Biederman
2021-10-21 8:09 ` Geert Uytterhoeven
2021-10-21 13:33 ` Eric W. Biederman
2021-10-21 8:32 ` Philippe Mathieu-Daudé
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