Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752713AbbBXTk5 (ORCPT ); Tue, 24 Feb 2015 14:40:57 -0500 Received: from mout.gmx.net ([212.227.17.21]:51819 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752387AbbBXTkz (ORCPT ); Tue, 24 Feb 2015 14:40:55 -0500 From: Heinrich Schuchardt To: Andrew Morton Cc: Aaron Tomlin , Andy Lutomirski , Davidlohr Bueso , David Rientjes , "David S. Miller" , Fabian Frederick , Guenter Roeck , "H. Peter Anvin" , Ingo Molnar , Jens Axboe , Joe Perches , Johannes Weiner , Kees Cook , Michael Marineau , Oleg Nesterov , "Paul E. McKenney" , Peter Zijlstra , Prarit Bhargava , Rik van Riel , Rusty Russell , Steven Rostedt , Thomas Gleixner , Vladimir Davydov , linux-kernel@vger.kernel.org, Heinrich Schuchardt Subject: [PATCH 3/3] kernel/sysctl.c: threads-max observe limits Date: Tue, 24 Feb 2015 20:38:21 +0100 Message-Id: <1424806701-30099-4-git-send-email-xypron.glpk@gmx.de> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1424806701-30099-1-git-send-email-xypron.glpk@gmx.de> References: <1424722477-23758-1-git-send-email-xypron.glpk@gmx.de> <1424806701-30099-1-git-send-email-xypron.glpk@gmx.de> X-Provags-ID: V03:K0:rQk4GylF9i1XCdcHYz70y17rrNBFUWdBPQeohSe6lz8+khU86cj w3ZE31obm00m1TxHImwlxCj6uhnWgL7eZN1CpcxBAGekF5Qq76GfcP0HXpBR3kflra/3Tza lsD4ZKC/QSYZjWE7PiIvubWopvloKKYNUjj7XQU0wkZ6RnN2Aa06G76Y2eFRaOnQ7qIwGM3 1NpgiUjqqzrGL20j84nPw== X-UI-Out-Filterresults: notjunk:1; Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2621 Lines: 101 Users can change the maximum number of threads by writing to /proc/sys/kernel/threads-max. With the patch the value entered is checked against the same limits that apply when fork_init is called. Signed-off-by: Heinrich Schuchardt --- include/linux/sysctl.h | 3 +++ kernel/fork.c | 24 ++++++++++++++++++++++++ kernel/sysctl.c | 6 ++---- 3 files changed, 29 insertions(+), 4 deletions(-) diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h index b7361f8..795d5fe 100644 --- a/include/linux/sysctl.h +++ b/include/linux/sysctl.h @@ -212,4 +212,7 @@ static inline void setup_sysctl_set(struct ctl_table_set *p, #endif /* CONFIG_SYSCTL */ +int sysctl_max_threads(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, loff_t *ppos); + #endif /* _LINUX_SYSCTL_H */ diff --git a/kernel/fork.c b/kernel/fork.c index 880c78d..52a07c7 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -74,6 +74,7 @@ #include #include #include +#include #include #include @@ -2024,3 +2025,26 @@ int unshare_files(struct files_struct **displaced) task_unlock(task); return 0; } + +int sysctl_max_threads(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, loff_t *ppos) +{ + struct ctl_table t; + int ret; + int threads = max_threads; + int min = MIN_THREADS; + int max = MAX_THREADS; + + t = *table; + t.data = &threads; + t.extra1 = &min; + t.extra2 = &max; + + ret = proc_dointvec_minmax(&t, write, buffer, lenp, ppos); + if (ret || !write) + return ret; + + set_max_threads(threads); + + return 0; +} diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 137c7f6..2e195ae 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -92,11 +92,9 @@ #include #endif - #if defined(CONFIG_SYSCTL) /* External variables not in a header file. */ -extern int max_threads; extern int suid_dumpable; #ifdef CONFIG_COREDUMP extern int core_uses_pid; @@ -709,10 +707,10 @@ static struct ctl_table kern_table[] = { #endif { .procname = "threads-max", - .data = &max_threads, + .data = NULL, .maxlen = sizeof(int), .mode = 0644, - .proc_handler = proc_dointvec, + .proc_handler = sysctl_max_threads, }, { .procname = "random", -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/