The patch titled
sysctl: use RCU protected sysctl for ocfs group add helper
has been added to the -mm tree. Its filename is
sysctl-use-rcu-protected-sysctl-for-ocfs-group-add-helper.patch
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See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: sysctl: use RCU protected sysctl for ocfs group add helper
From: Andi Kleen <andi@xxxxxxxxxxxxxx>
This avoids races with unlocked sysctl()
Also saves ~220 bytes in the data segment.
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxx>
Cc: Russell King <rmk+lkml@xxxxxxxxxxxxxxxx>
Cc: Sam Ravnborg <sam@xxxxxxxxxxxx>
Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Cc: Joel Becker <Joel.Becker@xxxxxxxxxx>
Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/ocfs2/stackglue.c | 17 +++++++++++++----
1 file changed, 13 insertions(+), 4 deletions(-)
diff -puN fs/ocfs2/stackglue.c~sysctl-use-rcu-protected-sysctl-for-ocfs-group-add-helper fs/ocfs2/stackglue.c
--- a/fs/ocfs2/stackglue.c~sysctl-use-rcu-protected-sysctl-for-ocfs-group-add-helper
+++ a/fs/ocfs2/stackglue.c
@@ -27,6 +27,7 @@
#include <linux/kobject.h>
#include <linux/sysfs.h>
#include <linux/sysctl.h>
+#include <linux/rcustring.h>
#include "ocfs2_fs.h"
@@ -40,7 +41,7 @@ static struct ocfs2_locking_protocol *lp
static DEFINE_SPINLOCK(ocfs2_stack_lock);
static LIST_HEAD(ocfs2_stack_list);
static char cluster_stack_name[OCFS2_STACK_LABEL_LEN + 1];
-static char ocfs2_hb_ctl_path[OCFS2_MAX_HB_CTL_PATH] = "/sbin/ocfs2_hb_ctl";
+static char *ocfs2_hb_ctl_path = "/sbin/ocfs2_hb_ctl";
/*
* The stack currently in use. If not null, active_stack->sp_count > 0,
@@ -395,8 +396,15 @@ static void ocfs2_leave_group(const char
{
int ret;
char *argv[5], *envp[3];
+ char *helper;
- argv[0] = ocfs2_hb_ctl_path;
+ helper = access_rcu_string(&ocfs2_hb_ctl_path, OCFS2_MAX_HB_CTL_PATH, GFP_KERNEL);
+ if (!helper) {
+ printk(KERN_ERR "ocfs2_leave_group: no memory\n");
+ return;
+ }
+
+ argv[0] = helper;
argv[1] = "-K";
argv[2] = "-u";
argv[3] = (char *)group;
@@ -414,6 +422,7 @@ static void ocfs2_leave_group(const char
"\"%s %s %s %s\"\n",
ret, argv[0], argv[1], argv[2], argv[3]);
}
+ kfree(helper);
}
/*
@@ -621,10 +630,10 @@ error:
static ctl_table ocfs2_nm_table[] = {
{
.procname = "hb_ctl_path",
- .data = ocfs2_hb_ctl_path,
+ .data = &ocfs2_hb_ctl_path,
.maxlen = OCFS2_MAX_HB_CTL_PATH,
.mode = 0644,
- .proc_handler = proc_dostring,
+ .proc_handler = proc_rcu_string,
},
{ }
};
_
Patches currently in -mm which might be from andi@xxxxxxxxxxxxxx are
kernel-signalc-fix-kernel-information-leak-with-print-fatal-signals=1.patch
proc-revert-procfs-provide-stack-information-for-threads.patch
kfifo-use-void-pointers-for-user-buffers.patch
kfifo-sanitize-_user-error-handling.patch
kfifo-add-kfifo_out_peek.patch
kfifo-add-kfifo_initialized.patch
kfifo-document-everywhere-that-size-has-to-be-power-of-two.patch
hardware-latency-detector-remove-default-m.patch
kbuild-move-fno-dwarf2-cfi-asm-to-powerpc-only.patch
mm-introduce-dump_page-and-print-symbolic-flag-names.patch
coredump-unify-dump_seek-implementations-for-each-binfmt_c.patch
coredump-move-dump_write-and-dump_seek-into-a-header-file.patch
elf-coredump-replace-elf_core_extra_-macros-by-functions.patch
elf-coredump-make-offset-calculation-process-and-writing-process-explicit.patch
elf-coredump-add-extended-numbering-support.patch
tracehooks-kill-some-pt_ptraced-checks.patch
tracehooks-check-pt_ptraced-before-reporting-the-single-step.patch
ptrace_signal-check-pt_ptraced-before-reporting-a-signal.patch
export-__ptrace_detach-and-do_notify_parent_cldstop.patch
reorder-the-code-in-kernel-ptracec.patch
implement-utrace-ptrace.patch
utrace-core.patch
rcu-add-rcustring-adt-for-rcu-protected-strings.patch
add-a-kernel_address-that-works-for-data-too.patch
sysctl-add-proc_rcu_string-to-manage-sysctls-using-rcu-strings.patch
sysctl-use-rcu-strings-for-core_pattern-sysctl.patch
sysctl-add-call_usermodehelper_cleanup.patch
sysctl-convert-modprobe_path-to-proc_rcu_string.patch
sysctl-convert-poweroff_command-to-proc_rcu_string.patch
sysctl-convert-hotplug-helper-string-to-proc_rcu_string.patch
sysctl-use-rcu-protected-sysctl-for-ocfs-group-add-helper.patch
--
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