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From: Heinrich Schuchardt <xypron.glpk@gmx.de>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Aaron Tomlin <atomlin@redhat.com>,
	Andy Lutomirski <luto@amacapital.net>,
	Davidlohr Bueso <dave@stgolabs.net>,
	David Rientjes <rientjes@google.com>,
	"David S. Miller" <davem@davemloft.net>,
	Fabian Frederick <fabf@skynet.be>,
	Guenter Roeck <linux@roeck-us.net>,
	"H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@kernel.org>,
	Jens Axboe <axboe@fb.com>, Joe Perches <joe@perches.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Jonathan Corbet <corbet@lwn.net>,
	Kees Cook <keescook@chromium.org>,
	Michael Marineau <mike@marineau.org>,
	Oleg Nesterov <oleg@redhat.com>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Prarit Bhargava <prarit@redhat.com>,
	Rik van Riel <riel@redhat.com>,
	Rusty Russell <rusty@rustcorp.com.au>,
	Steven Rostedt <rostedt@goodmis.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Vladimir Davydov <vdavydov@parallels.com>,
	linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
	Heinrich Schuchardt <xypron.glpk@gmx.de>
Subject: [PATCH 0/4 v6] max_threadx handling
Date: Sun, 15 Mar 2015 17:13:34 +0100	[thread overview]
Message-ID: <1426436018-5159-1-git-send-email-xypron.glpk@gmx.de> (raw)

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@linux-foundation.org>
  David Rientjes <rientjes@google.com>
  Guenter Roeck <linux@roeck-us.net>
  Ingo Molnar <mingo@kernel.org>
  Oleg Nesterov <oleg@redhat.com>
  Peter Zijlstra <peterz@infradead.org>
  Vladimir Davydov <vdavydov@parallels.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


             reply	other threads:[~2015-03-15 16:16 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-15 16:13 Heinrich Schuchardt [this message]
2015-03-15 16:13 ` [PATCH 1/4 v6] kernel/fork.c: new function for max_threads Heinrich Schuchardt
2015-03-15 16:13 ` [PATCH 2/4 v6] kernel/fork.c: avoid division by zero Heinrich Schuchardt
2015-03-16  7:41   ` Ingo Molnar
2015-03-17 19:19     ` Heinrich Schuchardt
2015-03-18 16:49       ` Ingo Molnar
2015-03-18 17:06         ` Oleg Nesterov
2015-03-25 12:25           ` Ingo Molnar
2015-03-15 16:13 ` [PATCH 3/4 v6] kernel/sysctl.c: threads-max observe limits Heinrich Schuchardt
2015-03-15 16:13 ` [PATCH 4/4 v6] Doc/sysctl/kernel.txt: document threads-max Heinrich Schuchardt
2015-03-15 16:30   ` Guenter Roeck
2015-03-25 18:59 ` [PATCH 0/4 v6] max_threadx handling Heinrich Schuchardt

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