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From: Andi Kleen <andi@firstfloor.org>
To: linux-kernel@vger.kernel.org, paulmck@linux.vnet.ibm.com,
	ebiederm@xmission.com
Subject: [PATCH] [4/11] SYSCTL: Use RCU strings for core_pattern sysctl
Date: Mon, 21 Dec 2009 02:20:25 +0100 (CET)	[thread overview]
Message-ID: <20091221012025.A2FA2B158A@basil.firstfloor.org> (raw)
In-Reply-To: <20091221220.243954235@firstfloor.org>


As a bonus this removes one use of the BKL.

Signed-off-by: Andi Kleen <ak@linux.intel.com>

---
 fs/exec.c       |    9 ++++-----
 kernel/sysctl.c |    6 +++---
 2 files changed, 7 insertions(+), 8 deletions(-)

Index: linux-2.6.33-rc1-ak/fs/exec.c
===================================================================
--- linux-2.6.33-rc1-ak.orig/fs/exec.c
+++ linux-2.6.33-rc1-ak/fs/exec.c
@@ -62,7 +62,7 @@
 #include "internal.h"
 
 int core_uses_pid;
-char core_pattern[CORENAME_MAX_SIZE] = "core";
+char *core_pattern = "core";
 unsigned int core_pipe_limit;
 int suid_dumpable = 0;
 
@@ -1825,12 +1825,11 @@ void do_coredump(long signr, int exit_co
 	clear_thread_flag(TIF_SIGPENDING);
 
 	/*
-	 * lock_kernel() because format_corename() is controlled by sysctl, which
-	 * uses lock_kernel()
+	 * Protect corename by RCU vs proc_rcu_string()
 	 */
- 	lock_kernel();
+	rcu_read_lock();
 	ispipe = format_corename(corename, signr);
-	unlock_kernel();
+	rcu_read_unlock();
 
 	if ((!ispipe) && (cprm.limit < binfmt->min_coredump))
 		goto fail_unlock;
Index: linux-2.6.33-rc1-ak/kernel/sysctl.c
===================================================================
--- linux-2.6.33-rc1-ak.orig/kernel/sysctl.c
+++ linux-2.6.33-rc1-ak/kernel/sysctl.c
@@ -75,7 +75,7 @@ extern int sysctl_oom_dump_tasks;
 extern int max_threads;
 extern int core_uses_pid;
 extern int suid_dumpable;
-extern char core_pattern[];
+extern char *core_pattern;
 extern unsigned int core_pipe_limit;
 extern int pid_max;
 extern int min_free_kbytes;
@@ -399,10 +399,10 @@ static struct ctl_table kern_table[] = {
 	},
 	{
 		.procname	= "core_pattern",
-		.data		= core_pattern,
+		.data		= &core_pattern,
 		.maxlen		= CORENAME_MAX_SIZE,
 		.mode		= 0644,
-		.proc_handler	= proc_dostring,
+		.proc_handler	= proc_rcu_string,
 	},
 	{
 		.procname	= "core_pipe_limit",

  parent reply	other threads:[~2009-12-21  1:20 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-12-21  1:20 [PATCH] [0/11] SYSCTL: Use RCU to avoid races with string sysctls Andi Kleen
2009-12-21  1:20 ` [PATCH] [1/11] Add rcustring ADT for RCU protected strings Andi Kleen
2009-12-22  2:46   ` Paul E. McKenney
2009-12-22 10:05     ` Andi Kleen
2009-12-22 20:59       ` Paul E. McKenney
2009-12-21  1:20 ` [PATCH] [2/11] Add a kernel_address() that works for data too Andi Kleen
2009-12-21  1:20 ` [PATCH] [3/11] SYSCTL: Add proc_rcu_string to manage sysctls using rcu strings Andi Kleen
2009-12-22  2:51   ` Paul E. McKenney
2009-12-22  3:00     ` Eric W. Biederman
2009-12-22  7:44       ` Paul E. McKenney
2009-12-21  1:20 ` Andi Kleen [this message]
2009-12-21  1:20 ` [PATCH] [5/11] SYSCTL: Add call_usermodehelper_cleanup() Andi Kleen
2009-12-21  1:20 ` [PATCH] [6/11] SYSCTL: Convert modprobe_path to proc_rcu_string() Andi Kleen
2009-12-21  1:20 ` [PATCH] [7/11] SYSCTL: Convert poweroff_command to proc_rcu_string Andi Kleen
2009-12-21  1:20 ` [PATCH] [8/11] SYSCTL: Convert hotplug helper string to proc_rcu_string() Andi Kleen
2009-12-22 19:03   ` Greg KH
2009-12-21  1:20 ` [PATCH] [9/11] SYSCTL: Add a mutex to the page_alloc zone order sysctl Andi Kleen
2009-12-21  1:20 ` [PATCH] [10/11] SYSCTL: Use RCU protected sysctl for ocfs group add helper Andi Kleen
2009-12-21  1:20 ` [PATCH] [11/11] SYSCTL: Convert IRDA text sysctl to RCU Andi Kleen
2009-12-21  1:59 ` [PATCH] [0/11] SYSCTL: Use RCU to avoid races with string sysctls Eric W. Biederman
2009-12-21  2:04   ` Andi Kleen
2009-12-21  2:31     ` Eric W. Biederman
2009-12-21  3:21       ` Andi Kleen

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