Revision d26d45253b78ec0a67003eea25bd08fceaa5b78c authored by Linus Torvalds on 22 January 2013, 18:30:49 UTC, committed by Linus Torvalds on 22 January 2013, 18:30:49 UTC
Pull ftrace fix from Steven Rostedt: "Kprobes now uses the function tracer if it can. That is, if a probe is placed on a function mcount/nop location, and the arch supports it, instead of adding a breakpoint, kprobes will register a function callback as that is much more efficient. The function tracer requires to update modules before they run, and uses the module notifier to do so. But if something else in the module notifiers registers a kprobe at one of these locations, before ftrace can get to it, then the system could fail. The function tracer must be initialized early, otherwise module notifiers that probe will only work by chance." * tag 'trace-3.8-rc4-fix' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: ftrace: Be first to run code modification on modules
do_mounts_initrd.c
/*
* Many of the syscalls used in this file expect some of the arguments
* to be __user pointers not __kernel pointers. To limit the sparse
* noise, turn off sparse checking for this file.
*/
#ifdef __CHECKER__
#undef __CHECKER__
#warning "Sparse checking disabled for this file"
#endif
#include <linux/unistd.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/minix_fs.h>
#include <linux/romfs_fs.h>
#include <linux/initrd.h>
#include <linux/sched.h>
#include <linux/freezer.h>
#include <linux/kmod.h>
#include "do_mounts.h"
unsigned long initrd_start, initrd_end;
int initrd_below_start_ok;
unsigned int real_root_dev; /* do_proc_dointvec cannot handle kdev_t */
static int __initdata mount_initrd = 1;
static int __init no_initrd(char *str)
{
mount_initrd = 0;
return 1;
}
__setup("noinitrd", no_initrd);
static int init_linuxrc(struct subprocess_info *info, struct cred *new)
{
sys_unshare(CLONE_FS | CLONE_FILES);
/* stdin/stdout/stderr for /linuxrc */
sys_open("/dev/console", O_RDWR, 0);
sys_dup(0);
sys_dup(0);
/* move initrd over / and chdir/chroot in initrd root */
sys_chdir("/root");
sys_mount(".", "/", NULL, MS_MOVE, NULL);
sys_chroot(".");
sys_setsid();
return 0;
}
static void __init handle_initrd(void)
{
static char *argv[] = { "linuxrc", NULL, };
extern char *envp_init[];
int error;
real_root_dev = new_encode_dev(ROOT_DEV);
create_dev("/dev/root.old", Root_RAM0);
/* mount initrd on rootfs' /root */
mount_block_root("/dev/root.old", root_mountflags & ~MS_RDONLY);
sys_mkdir("/old", 0700);
sys_chdir("/old");
/*
* In case that a resume from disk is carried out by linuxrc or one of
* its children, we need to tell the freezer not to wait for us.
*/
current->flags |= PF_FREEZER_SKIP;
call_usermodehelper_fns("/linuxrc", argv, envp_init, UMH_WAIT_PROC,
init_linuxrc, NULL, NULL);
current->flags &= ~PF_FREEZER_SKIP;
/* move initrd to rootfs' /old */
sys_mount("..", ".", NULL, MS_MOVE, NULL);
/* switch root and cwd back to / of rootfs */
sys_chroot("..");
if (new_decode_dev(real_root_dev) == Root_RAM0) {
sys_chdir("/old");
return;
}
sys_chdir("/");
ROOT_DEV = new_decode_dev(real_root_dev);
mount_root();
printk(KERN_NOTICE "Trying to move old root to /initrd ... ");
error = sys_mount("/old", "/root/initrd", NULL, MS_MOVE, NULL);
if (!error)
printk("okay\n");
else {
int fd = sys_open("/dev/root.old", O_RDWR, 0);
if (error == -ENOENT)
printk("/initrd does not exist. Ignored.\n");
else
printk("failed\n");
printk(KERN_NOTICE "Unmounting old root\n");
sys_umount("/old", MNT_DETACH);
printk(KERN_NOTICE "Trying to free ramdisk memory ... ");
if (fd < 0) {
error = fd;
} else {
error = sys_ioctl(fd, BLKFLSBUF, 0);
sys_close(fd);
}
printk(!error ? "okay\n" : "failed\n");
}
}
int __init initrd_load(void)
{
if (mount_initrd) {
create_dev("/dev/ram", Root_RAM0);
/*
* Load the initrd data into /dev/ram0. Execute it as initrd
* unless /dev/ram0 is supposed to be our actual root device,
* in that case the ram disk is just set up here, and gets
* mounted in the normal path.
*/
if (rd_load_image("/initrd.image") && ROOT_DEV != Root_RAM0) {
sys_unlink("/initrd.image");
handle_initrd();
return 1;
}
}
sys_unlink("/initrd.image");
return 0;
}
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