pivotroot does not work with initramfs

[Olaf Hering <olh@suse.de>]

I cant remount the root filesystem rw, mounting proc doesnt work either,
mount hangs, no userinput possible. System is a old powermac.
It seems pivotroot is either broken, or I dont use it correctly.

calltrace is:
c0073684 check_mnt

c0074584 do_remount
c003dc7c __alloc_pages
c0074cf0 do_mount
c007511c sys_mount
c000782c ret_from_syscall

#+ mount -t ext2 -o ro /udev/sda8 /mnt
+ umount /sys
+ cd /mnt
+ /bin/pivot_root . fw
+ chroot . /bin/bash --login
(none):/# mount -noremount,rw /
NIP: C0073684 LR: C0074584 SP: C050DE70 REGS: c050ddc0 TRAP: 0501    Not tainted
MSR: 00009030 EE: 1 PR: 0 FP: 0 ME: 1 IR/DR: 11
TASK = c4624080[160] 'mount' Last syscall: 21
GPR00: C47F54A0 C050DE70 C4624080 C47F5FA0 00000000 00000000 C471F000 C471F000
GPR08: 00000000 00000001 FFFFFFFF C47F5FA0 99000535
Call trace:
 [c0074cf0] do_mount+0x15c/0x168
 [c007511c] sys_mount+0xc8/0xf8
 [c000782c] ret_from_syscall+0x0/0x4c
Serial port locked ON by debugger !
Keyboard interrupt
vector: 501 at pc = c0073684, lr = c0074584
msr = 9030, sp = c050de70 [c050ddc0]
current = c4624080, pid = 160, comm = mount
mon> t
backtrace:
c003dc7c 
c0074cf0 
c007511c 
c000782c 
exception:c01 [c050df50] ff85abc 
10002608 
10003bb8 
10003ec0 
10004ef8 
0febfce4 
00000000 
mon> 

Total memory = 72MB; using 256kB for hash table (at c0380000)
Linux version 2.6.0-test9-7200 (builds@ibook) (gcc version 3.2.3 (SuSE Linux)) #143 Sun Nov 16 17:26:06 CET 2003




I use this script as /sbin/init for kinit:

#! /bin/ash
set -x
#mount -t proc proc /proc
#bb mkfs.minix /udev/ram0
#bb mv /dev/zero /dev/null /dev/console /udev
#mount -t minix /udev/ram0 /dev
#bb mv /udev/* /dev
#bb mkfs.minix /dev/ram1
mount -t ext2 -o ro /udev/sda8 /mnt
#mount -t minix /dev/ram1 /mnt/root
umount /sys
#umount /proc
#bb mv /dev/* /mnt/root/
#umount /dev
#umount /mnt/root
cd /mnt
#bb cat proc/mounts
/bin/pivot_root . fw
#exec
chroot . /bin/bash --login
echo done


I have to use this patch to make udev happy.


diff -x bin -x ash -x klibc-0.81 -purNX /home/olaf/kernel/kernel_exclude.txt linuxppc-2.5_2.6.0-test9-bk.orig/fs/binfmt_elf.c linuxppc-2.5_2.6.0-test9-bk/fs/binfmt_elf.c
--- linuxppc-2.5_2.6.0-test9-bk.orig/fs/binfmt_elf.c	2003-10-22 07:10:08.000000000 +0200
+++ linuxppc-2.5_2.6.0-test9-bk/fs/binfmt_elf.c	2003-11-15 19:01:38.000000000 +0100
@@ -1449,7 +1449,7 @@ cleanup:
 
 #endif		/* USE_ELF_CORE_DUMP */
 
-static int __init init_elf_binfmt(void)
+int init_elf_binfmt(void)
 {
 	return register_binfmt(&elf_format);
 }
@@ -1460,6 +1460,6 @@ static void __exit exit_elf_binfmt(void)
 	unregister_binfmt(&elf_format);
 }
 
-module_init(init_elf_binfmt)
+EXPORT_SYMBOL(init_elf_binfmt);
 module_exit(exit_elf_binfmt)
 MODULE_LICENSE("GPL");
diff -x bin -x ash -x klibc-0.81 -purNX /home/olaf/kernel/kernel_exclude.txt linuxppc-2.5_2.6.0-test9-bk.orig/init/do_mounts.c linuxppc-2.5_2.6.0-test9-bk/init/do_mounts.c
--- linuxppc-2.5_2.6.0-test9-bk.orig/init/do_mounts.c	2003-10-08 23:10:47.000000000 +0200
+++ linuxppc-2.5_2.6.0-test9-bk/init/do_mounts.c	2003-11-15 11:53:12.000000000 +0100
@@ -14,6 +14,7 @@
 #include "do_mounts.h"
 
 extern int get_filesystem_list(char * buf);
+extern asmlinkage long sys_access(const char * filename, int mode);
 
 int __initdata rd_doload;	/* 1 = load RAM disk, 0 = don't load */
 
@@ -370,6 +371,17 @@ void __init mount_root(void)
 	mount_block_root("/dev/root", root_mountflags);
 }
 
+static char *kinit_command;
+
+static int __init kinit_setup(char *str)
+{
+	kinit_command = str;
+	return 1;
+}
+
+__setup("kinit=", kinit_setup);
+
+
 /*
  * Prepare the namespace - decide what/where to mount, load ramdisks, etc.
  */
@@ -393,6 +405,16 @@ void __init prepare_namespace(void)
 	if (initrd_load())
 		goto out;
 
+	/*
+	 * check if there is an early userspace init, if yes
+	 * let it do all the work
+	 */
+	if (kinit_command || sys_access("/sbin/init", 0) == 0) {
+		extern char *execute_command;
+		execute_command = kinit_command ? kinit_command : 0;
+		goto out;
+	}
+
 	if (is_floppy && rd_doload && rd_load_disk(0))
 		ROOT_DEV = Root_RAM0;
 
diff -x bin -x ash -x klibc-0.81 -purNX /home/olaf/kernel/kernel_exclude.txt linuxppc-2.5_2.6.0-test9-bk.orig/init/initramfs.c linuxppc-2.5_2.6.0-test9-bk/init/initramfs.c
--- linuxppc-2.5_2.6.0-test9-bk.orig/init/initramfs.c	2003-10-18 17:25:50.000000000 +0200
+++ linuxppc-2.5_2.6.0-test9-bk/init/initramfs.c	2003-11-16 03:33:10.000000000 +0100
@@ -100,11 +100,11 @@ static void __init parse_header(char *s)
 {
 	unsigned long parsed[12];
 	char buf[9];
-	int i;
+	int i,j=1;
 
 	buf[8] = '\0';
 	for (i = 0, s += 6; i < 12; i++, s += 8) {
-		memcpy(buf, s, 8);
+		memcpy(buf, s, 7 + j);
 		parsed[i] = simple_strtoul(buf, NULL, 16);
 	}
 	ino = parsed[0];
@@ -493,6 +493,7 @@ void __init populate_rootfs(void)
 			printk(" it is\n");
 			unpack_to_rootfs((char *)initrd_start,
 				initrd_end - initrd_start, 0);
+			printk(" mount sysfs returned %ld\n", sys_mount("sys", "/sys","sysfs",NULL,NULL));
 			free_initrd_mem(initrd_start, initrd_end);
 			return;
 		}
diff -x bin -x ash -x klibc-0.81 -purNX /home/olaf/kernel/kernel_exclude.txt linuxppc-2.5_2.6.0-test9-bk.orig/init/main.c linuxppc-2.5_2.6.0-test9-bk/init/main.c
--- linuxppc-2.5_2.6.0-test9-bk.orig/init/main.c	2003-10-23 00:25:21.000000000 +0200
+++ linuxppc-2.5_2.6.0-test9-bk/init/main.c	2003-11-16 17:18:42.000000000 +0100
@@ -534,6 +534,7 @@ static void __init do_basic_setup(void)
 	sock_init();
 
 	init_workqueues();
+	init_elf_binfmt();
 	do_initcalls();
 }
 
diff -x bin -x ash -x klibc-0.81 -purNX /home/olaf/kernel/kernel_exclude.txt linuxppc-2.5_2.6.0-test9-bk.orig/kernel/kmod.c linuxppc-2.5_2.6.0-test9-bk/kernel/kmod.c
--- linuxppc-2.5_2.6.0-test9-bk.orig/kernel/kmod.c	2003-10-22 07:10:02.000000000 +0200
+++ linuxppc-2.5_2.6.0-test9-bk/kernel/kmod.c	2003-11-16 04:49:55.000000000 +0100
@@ -249,7 +249,7 @@ int call_usermodehelper(char *path, char
 	};
 	DECLARE_WORK(work, __call_usermodehelper, &sub_info);
 
-	if (!system_running)
+	if (0 && !system_running)
 		return -EBUSY;
 
 	if (path[0] == '\0')
diff -x bin -x ash -x klibc-0.81 -purNX /home/olaf/kernel/kernel_exclude.txt linuxppc-2.5_2.6.0-test9-bk.orig/usr/Makefile linuxppc-2.5_2.6.0-test9-bk/usr/Makefile
--- linuxppc-2.5_2.6.0-test9-bk.orig/usr/Makefile	2003-08-04 01:59:27.000000000 +0200
+++ linuxppc-2.5_2.6.0-test9-bk/usr/Makefile	2003-11-16 15:58:53.000000000 +0100
@@ -3,7 +3,14 @@ obj-y := initramfs_data.o
 
 host-progs  := gen_init_cpio
 
-clean-files := initramfs_data.cpio.gz
+clean-files := initramfs_data.cpio.gz sbin/hotplug
+
+$(obj)/ash/sh.static: $(obj)/ash/Makefile
+	cd $(obj)/ash ; make
+
+$(obj)/sbin/hotplug: $(obj)/sbin/hotplug.c
+	diet gcc -Wall -o $@ -Os $< -s -static
+
 
 # initramfs_data.o contains the initramfs_data.cpio.gz image.
 # The image is included using .incbin, a dependency which is not
@@ -16,7 +23,8 @@ $(obj)/initramfs_data.o: $(obj)/initramf
 # here.
 
 # Commented out for now
-# initramfs-y := $(obj)/root/hello
+initramfs-y := $(obj)/ash/sh.static $(obj)/bin/chroot $(obj)/bin/dd $(obj)/bin/fstype $(obj)/bin/mkdir $(obj)/bin/mkfifo $(obj)/bin/mount $(obj)/bin/pivot_root $(obj)/bin/umount $(obj)/busybox $(obj)/mounts $(obj)/myinit.sh $(obj)/sbin/hotplug $(obj)/sbin/udev /bin/sash
+
 
 quiet_cmd_cpio = CPIO    $@
       cmd_cpio = ./$< > $@
@@ -28,6 +36,7 @@ targets += initramfs_data.cpio
 
 $(obj)/initramfs_data.cpio.gz: $(obj)/initramfs_data.cpio FORCE
 	$(call if_changed,gzip)
+	/bin/gzip -cd $@ | cpio -vt
 
 targets += initramfs_data.cpio.gz
 
Binary files linuxppc-2.5_2.6.0-test9-bk.orig/usr/busybox and linuxppc-2.5_2.6.0-test9-bk/usr/busybox differ
diff -x bin -x ash -x klibc-0.81 -purNX /home/olaf/kernel/kernel_exclude.txt linuxppc-2.5_2.6.0-test9-bk.orig/usr/gen_init_cpio.c linuxppc-2.5_2.6.0-test9-bk/usr/gen_init_cpio.c
--- linuxppc-2.5_2.6.0-test9-bk.orig/usr/gen_init_cpio.c	2003-09-07 05:58:23.000000000 +0200
+++ linuxppc-2.5_2.6.0-test9-bk/usr/gen_init_cpio.c	2003-11-16 15:59:09.000000000 +0100
@@ -197,6 +197,7 @@ void cpio_mkfile(const char *filename, c
 
 	for (i = 0; i < buf.st_size; ++i)
 		fputc(filebuf[i], stdout);
+	offset += buf.st_size;
 	close(file);
 	free(filebuf);
 	push_pad();
@@ -212,9 +213,51 @@ error:
 
 int main (int argc, char *argv[])
 {
+	cpio_mkdir("/etc", 0755, 0, 0);
+	cpio_mkdir("/etc/udev", 0755, 0, 0);
 	cpio_mkdir("/dev", 0755, 0, 0);
-	cpio_mknod("/dev/console", 0600, 0, 0, 'c', 5, 1);
-	cpio_mkdir("/root", 0700, 0, 0);
+	cpio_mknod("/dev/console",	0600, 0, 0, 'c', 5, 1);
+	cpio_mknod("/dev/null",		0600, 0, 0, 'c', 1, 3);
+	cpio_mknod("/dev/zero",		0600, 0, 0, 'c', 1, 5);
+	cpio_mknod("/dev/ram0",		0600, 0, 0, 'b', 1, 0);
+	cpio_mkdir("/fw", 0700, 0, 0);
+	cpio_mkdir("/mnt", 0700, 0, 0);
+	cpio_mkdir("/proc", 0700, 0, 0);
+	cpio_mkdir("/sys", 0700, 0, 0);
+	cpio_mkdir("/bin", 0700, 0, 0);
+	cpio_mkdir("/sbin", 0700, 0, 0);
+	cpio_mkdir("/tmp", 0700, 0, 0);
+	cpio_mkdir("/udev", 0700, 0, 0);
+	cpio_mkfile("usr/mounts", "/proc/mounts", 0700, 0, 0);
+#if 0
+	cpio_mkfile("usr/sbin/hotplug", "/sbin/hotplug", 0700, 0, 0);
+	cpio_mkfile("usr/sbin/udev", "/bin/udev", 0700, 0, 0);
+#else
+	cpio_mkfile("usr/sbin/udev", "/sbin/hotplug", 0700, 0, 0);
+#endif
+	cpio_mkfile("usr/busybox", "/bin/bb", 0700, 0, 0);
+#if 0
+	cpio_mkfile("/bin/sash", "/sbin/init", 0700, 0, 0);
+	cpio_mkfile("usr/ash/sh.static", "/bin/sh", 0700, 0, 0);
+#else
+	cpio_mkfile("usr/ash/sh.static", "/bin/ash", 0700, 0, 0);
+	cpio_mkfile("/bin/sash", "/bin/sash", 0700, 0, 0);
+#endif
+#if 0
+	cpio_mkfile("usr/bin/dd","/bin/dd",0700,0,0);
+	cpio_mkfile("usr/bin/fstype","/bin/fstype",0700,0,0);
+	cpio_mkfile("usr/bin/mkdir","/bin/mkdir",0700,0,0);
+	cpio_mkfile("usr/bin/mkfifo","/bin/mkfifo",0700,0,0);
+#endif
+#if 1
+	cpio_mkfile("usr/bin/mount","/bin/mount",0700,0,0);
+	cpio_mkfile("usr/bin/umount","/bin/umount",0700,0,0);
+#endif
+#if 1
+	cpio_mkfile("usr/bin/chroot","/bin/chroot",0700,0,0);
+	cpio_mkfile("usr/bin/pivot_root","/bin/pivot_root",0700,0,0);
+#endif
+	cpio_mkfile("usr/myinit.sh", "/sbin/init", 0700, 0, 0);
 	cpio_trailer();
 
 	exit(0);
Binary files linuxppc-2.5_2.6.0-test9-bk.orig/usr/initramfs_data.cpio and linuxppc-2.5_2.6.0-test9-bk/usr/initramfs_data.cpio differ
diff -x bin -x ash -x klibc-0.81 -purNX /home/olaf/kernel/kernel_exclude.txt linuxppc-2.5_2.6.0-test9-bk.orig/usr/mounts linuxppc-2.5_2.6.0-test9-bk/usr/mounts
--- linuxppc-2.5_2.6.0-test9-bk.orig/usr/mounts	1970-01-01 01:00:00.000000000 +0100
+++ linuxppc-2.5_2.6.0-test9-bk/usr/mounts	2003-11-16 03:49:04.000000000 +0100
@@ -0,0 +1,3 @@
+rootfs / rootfs rw 0 0
+sys /sys sysfs rw 0 0
+proc /proc proc rw 0 0
diff -x bin -x ash -x klibc-0.81 -purNX /home/olaf/kernel/kernel_exclude.txt linuxppc-2.5_2.6.0-test9-bk.orig/usr/myinit.sh linuxppc-2.5_2.6.0-test9-bk/usr/myinit.sh
--- linuxppc-2.5_2.6.0-test9-bk.orig/usr/myinit.sh	1970-01-01 01:00:00.000000000 +0100
+++ linuxppc-2.5_2.6.0-test9-bk/usr/myinit.sh	2003-11-16 17:04:04.000000000 +0100
@@ -0,0 +1,21 @@
+#! /bin/ash
+set -x
+#mount -t proc proc /proc
+#bb mkfs.minix /udev/ram0
+#bb mv /dev/zero /dev/null /dev/console /udev
+#mount -t minix /udev/ram0 /dev
+#bb mv /udev/* /dev
+#bb mkfs.minix /dev/ram1
+mount -t ext2 -o ro /udev/sda8 /mnt
+#mount -t minix /dev/ram1 /mnt/root
+umount /sys
+#umount /proc
+#bb mv /dev/* /mnt/root/
+#umount /dev
+#umount /mnt/root
+cd /mnt
+#bb cat proc/mounts
+/bin/pivot_root . fw
+#exec
+chroot . /bin/bash --login
+echo done
Binary files linuxppc-2.5_2.6.0-test9-bk.orig/usr/sbin/hotplug and linuxppc-2.5_2.6.0-test9-bk/usr/sbin/hotplug differ
diff -x bin -x ash -x klibc-0.81 -purNX /home/olaf/kernel/kernel_exclude.txt linuxppc-2.5_2.6.0-test9-bk.orig/usr/sbin/hotplug.c linuxppc-2.5_2.6.0-test9-bk/usr/sbin/hotplug.c
--- linuxppc-2.5_2.6.0-test9-bk.orig/usr/sbin/hotplug.c	1970-01-01 01:00:00.000000000 +0100
+++ linuxppc-2.5_2.6.0-test9-bk/usr/sbin/hotplug.c	2003-11-15 21:01:49.000000000 +0100
@@ -0,0 +1,47 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+#define BUFSIZE 12345
+int
+main(int argc, char **argv, char **envp)
+{
+	int fd, i;
+	char **ep = envp;
+	char *buf, *p;
+	sleep(42);
+	buf = malloc(42);
+	if (!buf)
+		exit(1);
+	p = getenv("SEQNUM");
+	snprintf(buf, 42, "/udev/x/dbg.%08u.%s", getpid(), p ? p : "");
+	if ((fd = open(buf, O_CREAT | O_WRONLY | O_TRUNC, 0644)) < 0) {
+		//perror(buf);
+		exit(1);
+	}
+	free(buf);
+	p = malloc(BUFSIZE);
+	buf = p;
+	for (i = 0; i < argc; ++i) {
+		buf += snprintf(buf, p + BUFSIZE - buf, " %s", argv[i]);
+		if (buf > p + BUFSIZE)
+			goto full;
+	}
+	buf += snprintf(buf, p + BUFSIZE - buf, "\n");
+	if (buf > p + BUFSIZE)
+		goto full;
+	while (*ep) {
+		buf += snprintf(buf, p + BUFSIZE - buf, "%s\n", *ep++);
+		if (buf > p + BUFSIZE)
+			break;
+	}
+      full:
+	buf = p;
+	write(fd, buf, strlen(buf));
+	close(fd);
+	free(buf);
+	return 0;
+}
Binary files linuxppc-2.5_2.6.0-test9-bk.orig/usr/sbin/udev and linuxppc-2.5_2.6.0-test9-bk/usr/sbin/udev differ
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