All of lore.kernel.org
 help / color / mirror / Atom feed
From: ebiederm@xmission.com (Eric W. Biederman)
To: <linux-kernel@vger.kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>, Will Deacon <will@kernel.org>,
	Jann Horn <jannh@google.com>,
	Vasiliy Kulikov <segoon@openwall.com>,
	Al Viro <viro@zeniv.linux.org.uk>,
	Bernd Edlinger <bernd.edlinger@hotmail.de>,
	Oleg Nesterov <oleg@redhat.com>,
	Christopher Yeoh <cyeoh@au1.ibm.com>,
	Cyrill Gorcunov <gorcunov@gmail.com>,
	Sargun Dhillon <sargun@sargun.me>,
	Christian Brauner <christian.brauner@ubuntu.com>,
	Arnd Bergmann <arnd@arndb.de>,
	Arnaldo Carvalho de Melo <acme@kernel.org>
Subject: [PATCH 0/3] exec: Transform exec_update_mutex into a rw_semaphore
Date: Thu, 03 Dec 2020 14:09:39 -0600	[thread overview]
Message-ID: <87tut2bqik.fsf@x220.int.ebiederm.org> (raw)


Recently syzbot reported[0] that there is a deadlock amongst the users
of exec_update_mutex.

The simplest and most robust solution appears to be making
exec_update_mutex a read/write lock and having everything execept for
exec take the lock for read.

This set of changes upgrades rwsem so it has the functionality needed
and uses a rw_semaphore to replace the current mutex.

Eric W. Biederman (3):
      rwsem: Implement down_read_killable_nested
      rwsem: Implement down_read_interruptible
      exec: Transform exec_update_mutex into a rw_semaphore

 fs/exec.c                    | 12 ++++++------
 fs/proc/base.c               | 10 +++++-----
 include/linux/rwsem.h        |  3 +++
 include/linux/sched/signal.h | 11 ++++++-----
 init/init_task.c             |  2 +-
 kernel/events/core.c         | 12 ++++++------
 kernel/fork.c                |  6 +++---
 kernel/kcmp.c                | 30 +++++++++++++++---------------
 kernel/locking/rwsem.c       | 40 ++++++++++++++++++++++++++++++++++++++++
 kernel/pid.c                 |  4 ++--
 10 files changed, 87 insertions(+), 43 deletions(-)

[0] https://lkml.kernel.org/r/00000000000063640c05ade8e3de@google.com

Eric

             reply	other threads:[~2020-12-03 20:11 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-03 20:09 Eric W. Biederman [this message]
2020-12-03 20:10 ` [PATCH 1/3] rwsem: Implement down_read_killable_nested Eric W. Biederman
2020-12-04  1:58   ` Waiman Long
2020-12-09 18:38   ` [tip: locking/core] " tip-bot2 for Eric W. Biederman
2020-12-03 20:11 ` [PATCH 2/3] rwsem: Implement down_read_interruptible Eric W. Biederman
2020-12-04  1:59   ` Waiman Long
2020-12-07  9:02     ` Peter Zijlstra
2020-12-07 15:33       ` Waiman Long
2020-12-07 16:58         ` David Laight
2020-12-07 19:02           ` Waiman Long
2020-12-08  9:12             ` David Laight
2020-12-08 12:32               ` Peter Zijlstra
2020-12-08 13:13                 ` David Laight
2020-12-08 15:34               ` Waiman Long
2020-12-08 16:23                 ` David Laight
2020-12-07 15:56       ` Eric W. Biederman
2020-12-08 14:52         ` Peter Zijlstra
2020-12-08 18:27           ` Eric W. Biederman
2020-12-09 18:36             ` Peter Zijlstra
2020-12-10 19:33               ` Eric W. Biederman
2020-12-11  8:16                 ` Peter Zijlstra
2020-12-09 18:38       ` [tip: locking/core] locking/rwsem: Introduce rwsem_write_trylock() tip-bot2 for Peter Zijlstra
2020-12-09 18:38       ` [tip: locking/core] locking/rwsem: Fold __down_{read,write}*() tip-bot2 for Peter Zijlstra
2020-12-09 18:38       ` [tip: locking/core] locking/rwsem: Better collate rwsem_read_trylock() tip-bot2 for Peter Zijlstra
2020-12-09 18:38   ` [tip: locking/core] rwsem: Implement down_read_interruptible tip-bot2 for Eric W. Biederman
2020-12-03 20:12 ` [PATCH 3/3] exec: Transform exec_update_mutex into a rw_semaphore Eric W. Biederman
2020-12-04 16:08   ` Bernd Edlinger
2020-12-04 17:21     ` Linus Torvalds
2020-12-04 19:34       ` Eric W. Biederman
2020-12-04 20:10         ` Linus Torvalds
2020-12-04 20:30           ` Bernd Edlinger
2020-12-04 20:48             ` Linus Torvalds
2020-12-04 21:48               ` Davidlohr Bueso
2020-12-05 18:05                 ` Eric W. Biederman
2020-12-07  9:15                   ` Peter Zijlstra
2020-12-07  9:09               ` Peter Zijlstra
2020-12-07 18:40                 ` Linus Torvalds
2020-12-08  8:34                   ` [PATCH] perf: Break deadlock involving exec_update_mutex Peter Zijlstra
2020-12-08 18:37                     ` Linus Torvalds
2020-12-10 18:38                     ` Davidlohr Bueso
2020-12-10 19:40                       ` Eric W. Biederman
2020-12-05 17:43           ` [PATCH 3/3] exec: Transform exec_update_mutex into a rw_semaphore Eric W. Biederman
2020-12-04 17:39     ` Eric W. Biederman
2020-12-03 22:42 ` [PATCH 0/3] " Linus Torvalds
2020-12-04  1:56   ` Waiman Long
2020-12-04  4:54   ` Davidlohr Bueso

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=87tut2bqik.fsf@x220.int.ebiederm.org \
    --to=ebiederm@xmission.com \
    --cc=acme@kernel.org \
    --cc=arnd@arndb.de \
    --cc=bernd.edlinger@hotmail.de \
    --cc=christian.brauner@ubuntu.com \
    --cc=cyeoh@au1.ibm.com \
    --cc=gorcunov@gmail.com \
    --cc=jannh@google.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mingo@redhat.com \
    --cc=oleg@redhat.com \
    --cc=peterz@infradead.org \
    --cc=sargun@sargun.me \
    --cc=segoon@openwall.com \
    --cc=torvalds@linux-foundation.org \
    --cc=viro@zeniv.linux.org.uk \
    --cc=will@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.