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From: Oleg Nesterov <oleg@redhat.com>
To: Jann Horn <jann@thejh.net>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>,
	Roland McGrath <roland@hack.frob.com>,
	John Johansen <john.johansen@canonical.com>,
	James Morris <james.l.morris@oracle.com>,
	"Serge E. Hallyn" <serge@hallyn.com>,
	Paul Moore <aul@paul-moore.com>,
	Stephen Smalley <sds@tycho.nsa.gov>,
	Eric Paris <eparis@parisplace.org>,
	Casey Schaufler <casey@schaufler-ca.com>,
	Kees Cook <keescook@chromium.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Janis Danisevskis <jdanis@google.com>,
	Seth Forshee <seth.forshee@canonical.com>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Benjamin LaHaise <bcrl@kvack.org>,
	Ben Hutchings <ben@decadent.org.uk>,
	Andy Lutomirski <luto@amacapital.net>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Krister Johansen <kjlx@templeofstupid.com>,
	linux-fsdevel@vger.kernel.org,
	linux-security-module@vger.kernel.org, security@kernel.org
Subject: Re: [PATCH v3 1/8] exec: introduce cred_guard_light
Date: Wed, 2 Nov 2016 19:18:06 +0100
Message-ID: <20161102181806.GB1112@redhat.com> (raw)
In-Reply-To: <1477863998-3298-2-git-send-email-jann@thejh.net>

On 10/30, Jann Horn wrote:
>
> This is a new per-threadgroup lock that can often be taken instead of
> cred_guard_mutex and has less deadlock potential. I'm doing this because
> Oleg Nesterov mentioned the potential for deadlocks, in particular if a
> debugged task is stuck in execve, trying to get rid of a ptrace-stopped
> thread, and the debugger attempts to inspect procfs files of the debugged
> task.

Yes, but let me repeat that we need to fix this anyway. So I don't really
understand why should we add yet another mutex.

Oleg.


  reply index

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-10-30 21:46 [PATCH v3 0/8] Various fixes related to ptrace_may_access() Jann Horn
2016-10-30 21:46 ` [PATCH v3 1/8] exec: introduce cred_guard_light Jann Horn
2016-11-02 18:18   ` Oleg Nesterov [this message]
2016-11-02 20:50     ` Jann Horn
2016-11-02 21:38       ` Ben Hutchings
2016-11-02 21:54         ` Jann Horn
2016-11-03 18:12       ` Oleg Nesterov
2016-11-03 21:17         ` Jann Horn
2016-11-04 13:26         ` Eric W. Biederman
2016-11-04 15:00           ` Eric W. Biederman
2016-11-04 18:04             ` Oleg Nesterov
2016-11-04 18:45               ` Oleg Nesterov
2016-11-05 14:56                 ` Oleg Nesterov
2016-11-09  0:34                   ` Eric W. Biederman
2016-11-16 20:03                   ` Eric W. Biederman
2016-11-08 22:02                 ` Kees Cook
2016-11-08 22:46                   ` Eric W. Biederman
2016-11-08 22:56                     ` Benjamin LaHaise
2016-11-08 23:33                       ` Eric W. Biederman
2016-10-30 21:46 ` [PATCH v3 2/8] exec: add privunit to task_struct Jann Horn
2016-10-30 21:46 ` [PATCH v3 3/8] proc: use open()-time creds for ptrace checks Jann Horn
2016-10-30 21:46 ` [PATCH v3 4/8] futex: don't leak robust_list pointer Jann Horn
2016-10-30 21:46 ` [PATCH v3 5/8] proc: lock properly in ptrace_may_access callers Jann Horn
2016-10-30 21:46 ` [PATCH v3 6/8] fs/proc: fix attr access check Jann Horn
2016-10-30 21:46 ` [PATCH v3 7/8] proc: fix timerslack_ns handling Jann Horn
2016-10-30 21:46 ` [PATCH v3 8/8] Documentation: add security/ptrace_checks.txt Jann Horn
2016-11-01 23:57 ` [PATCH v3 0/8] Various fixes related to ptrace_may_access() Linus Torvalds
2016-11-02 18:38   ` Oleg Nesterov
2016-11-02 21:40     ` Jann Horn
2016-11-03 19:09   ` Andrew Morton
2016-11-03 20:01     ` Jann Horn
2016-11-04  0:57   ` James Morris

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