linux-kernel - [PATCH 0/4 v6] max

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Message-Id: <1426436018-5159-1-git-send-email-xypron.glpk@gmx.de>
Date:	Sun, 15 Mar 2015 17:13:34 +0100
From:	Heinrich Schuchardt <xypron.glpk@....de>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Aaron Tomlin <atomlin@...hat.com>,
	Andy Lutomirski <luto@...capital.net>,
	Davidlohr Bueso <dave@...olabs.net>,
	David Rientjes <rientjes@...gle.com>,
	"David S. Miller" <davem@...emloft.net>,
	Fabian Frederick <fabf@...net.be>,
	Guenter Roeck <linux@...ck-us.net>,
	"H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...nel.org>,
	Jens Axboe <axboe@...com>, Joe Perches <joe@...ches.com>,
	Johannes Weiner <hannes@...xchg.org>,
	Jonathan Corbet <corbet@....net>,
	Kees Cook <keescook@...omium.org>,
	Michael Marineau <mike@...ineau.org>,
	Oleg Nesterov <oleg@...hat.com>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Prarit Bhargava <prarit@...hat.com>,
	Rik van Riel <riel@...hat.com>,
	Rusty Russell <rusty@...tcorp.com.au>,
	Steven Rostedt <rostedt@...dmis.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Vladimir Davydov <vdavydov@...allels.com>,
	linux-kernel@...r.kernel.org, linux-doc@...r.kernel.org,
	Heinrich Schuchardt <xypron.glpk@....de>
Subject: [PATCH 0/4 v6] max_threadx handling

In fork_init a division by zero may occur.

In the first patch the calculation of max_threads is moved from fork_init
to a new separate function.

The incorrect calculation of max threads is addressed in the 
second patch.

Furthermore max_threads is checked against FUTEX_TID_MASK.

The third patch addresses max_threads being set by writing to
/proc/sys/kernel/threads-max. The same limits are applied as
in fork_init.

The fourth patch adds a description of threads-max to
Documentation/sysctl/kernel.txt.

New in version 6:
  Check against overflow of totalram_pages * PAGE_SIZE.
  Introduce argument of set_max_threads in 3rd patch where it is needed,
  not before.
  Update Documentation/sysctl/kernel.txt concerning threads-max.

New in version 5:
  Do not update limits of the init process
  Do not update max_threads on memory hotplug events
  Corrections to commit messages

New in version 4:
  Separation of refactoring and correction into separate patches
  (as requested by Ingo Molnar)
  Remove redundant argument of fork_init

New in version 3:
  Determination of max_threads moved to separate function.
  Handling of /proc/sys/kernel/threads-max
  Handling of memory hotplugging.

New in version 2:
  Use div64_u64 for 64-bit division.

Thank you for your helpful feedback:
  Andrew Morton <akpm@...ux-foundation.org>
  David Rientjes <rientjes@...gle.com>
  Guenter Roeck <linux@...ck-us.net>
  Ingo Molnar <mingo@...nel.org>
  Oleg Nesterov <oleg@...hat.com>
  Peter Zijlstra <peterz@...radead.org>
  Vladimir Davydov <vdavydov@...allels.com>

Heinrich Schuchardt (4):
  kernel/fork.c: new function for max_threads
  kernel/fork.c: avoid division by zero
  kernel/sysctl.c: threads-max observe limits
  Doc/sysctl/kernel.txt: document threads-max

 Documentation/sysctl/kernel.txt | 21 +++++++++++
 include/linux/sysctl.h          |  3 ++
 init/main.c                     |  4 +--
 kernel/fork.c                   | 78 ++++++++++++++++++++++++++++++++++-------
 kernel/sysctl.c                 |  6 ++--
 5 files changed, 93 insertions(+), 19 deletions(-)

-- 
2.1.4

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