From mboxrd@z Thu Jan 1 00:00:00 1970 From: akpm@linux-foundation.org Subject: + sysctl-convert-poweroff_command-to-proc_rcu_string.patch added to -mm tree Date: Fri, 08 Jan 2010 15:54:15 -0800 Message-ID: <201001082354.o08NsFD4021880@imap1.linux-foundation.org> Reply-To: linux-kernel@vger.kernel.org Return-path: Received: from smtp1.linux-foundation.org ([140.211.169.13]:50409 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754434Ab0AHXya (ORCPT ); Fri, 8 Jan 2010 18:54:30 -0500 Sender: mm-commits-owner@vger.kernel.org List-Id: mm-commits@vger.kernel.org To: mm-commits@vger.kernel.org Cc: andi@firstfloor.org, ak@linux.intel.com, ebiederm@xmission.com, paulmck@us.ibm.com, rmk+lkml@arm.linux.org.uk, rusty@rustcorp.com.au, sam@ravnborg.org The patch titled sysctl: convert poweroff_command to proc_rcu_string has been added to the -mm tree. Its filename is sysctl-convert-poweroff_command-to-proc_rcu_string.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** 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: convert poweroff_command to proc_rcu_string From: Andi Kleen Avoids races with lockless sysctl. Also saves ~220 bytes in the data segment for default kernels. Signed-off-by: Andi Kleen Cc: "Paul E. McKenney" Cc: Russell King Cc: Sam Ravnborg Cc: "Eric W. Biederman" Cc: Rusty Russell Signed-off-by: Andrew Morton --- include/linux/reboot.h | 2 +- kernel/sys.c | 8 ++++++-- kernel/sysctl.c | 2 +- 3 files changed, 8 insertions(+), 4 deletions(-) diff -puN include/linux/reboot.h~sysctl-convert-poweroff_command-to-proc_rcu_string include/linux/reboot.h --- a/include/linux/reboot.h~sysctl-convert-poweroff_command-to-proc_rcu_string +++ a/include/linux/reboot.h @@ -67,7 +67,7 @@ extern void kernel_power_off(void); void ctrl_alt_del(void); #define POWEROFF_CMD_PATH_LEN 256 -extern char poweroff_cmd[POWEROFF_CMD_PATH_LEN]; +extern char *poweroff_cmd; extern int orderly_poweroff(bool force); diff -puN kernel/sys.c~sysctl-convert-poweroff_command-to-proc_rcu_string kernel/sys.c --- a/kernel/sys.c~sysctl-convert-poweroff_command-to-proc_rcu_string +++ a/kernel/sys.c @@ -1726,7 +1726,7 @@ SYSCALL_DEFINE3(getcpu, unsigned __user return err ? -EFAULT : 0; } -char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff"; +char *poweroff_cmd = "/sbin/poweroff"; static void argv_cleanup(char **argv, char **envp) { @@ -1743,7 +1743,7 @@ static void argv_cleanup(char **argv, ch int orderly_poweroff(bool force) { int argc; - char **argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc); + char **argv; static char *envp[] = { "HOME=/", "PATH=/sbin:/bin:/usr/sbin:/usr/bin", @@ -1752,6 +1752,10 @@ int orderly_poweroff(bool force) int ret = -ENOMEM; struct subprocess_info *info; + /* RCU protection for poweroff_cmd */ + rcu_read_lock(); + argv = argv_split(GFP_ATOMIC, rcu_dereference(poweroff_cmd), &argc); + rcu_read_unlock(); if (argv == NULL) { printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n", __func__, poweroff_cmd); diff -puN kernel/sysctl.c~sysctl-convert-poweroff_command-to-proc_rcu_string kernel/sysctl.c --- a/kernel/sysctl.c~sysctl-convert-poweroff_command-to-proc_rcu_string +++ a/kernel/sysctl.c @@ -871,7 +871,7 @@ static struct ctl_table kern_table[] = { .data = &poweroff_cmd, .maxlen = POWEROFF_CMD_PATH_LEN, .mode = 0644, - .proc_handler = proc_dostring, + .proc_handler = proc_rcu_string, }, #ifdef CONFIG_KEYS { _ Patches currently in -mm which might be from andi@firstfloor.org 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