[uml-user] Kernel panic - not syncing: No init found using initramfs

[kail-gj <an_...@12...>]

Hi, 
    I build my uml from source with CONFIG_INITRAMFS_SOURCE configured with a rootfs text file.  I specify the init file to  busybox as
    file /bin/busybox /home/xxxx/busybox/busybox 755 0 0 /init /bin/sh in rootfs text file. 
    But it does not work and output "kernel panic - not syncing: No init found" error. The full boot log is followed. 
    Please help me, thanks.
-------------------------------------------------
boot log:
-------------------------------------------------
$ ./linux 
Core dump limits :
soft - 0
hard - NONE
Checking that ptrace can change system call numbers...OK
Checking syscall emulation patch for ptrace...OK
Checking advanced syscall emulation patch for ptrace...OK
Checking for tmpfs mount on /dev/shm...OK
Checking PROT_EXEC mmap in /dev/shm/...OK
Checking for the skas3 patch in the host:
  - /proc/mm...not found: No such file or directory
  - PTRACE_FAULTINFO...not found
  - PTRACE_LDT...not found
UML running in SKAS0 mode
Linux version 2.6.32.8 (chipX /home/chipX/chipX/fhos/trunk/build.um.d/linux@suzhou-chipX) (gcc version 4.4.7 20120313 (Red Hat 4.4.7-3) (GCC) ) #1 Sun May 15 17:42:40 CST 2016
Built 1 zonelists in Zone order, mobility grouping on.  Total pages: 8080
Kernel command line: root=98:0
PID hash table entries: 128 (order: -2, 1024 bytes)
Dentry cache hash table entries: 4096 (order: 3, 32768 bytes)
Inode-cache hash table entries: 2048 (order: 2, 16384 bytes)
Memory: 28892k available
Hierarchical RCU implementation.
NR_IRQS:15
Calibrating delay loop... 91.54 BogoMIPS (lpj=457728)
Mount-cache hash table entries: 256
Checking that host ptys support output SIGIO...Yes
Checking that host ptys support SIGIO on close...No, enabling workaround
Using 2.6 host AIO
NET: Registered protocol family 16
Switching to clocksource itimer
NET: Registered protocol family 2
IP route cache hash table entries: 512 (order: 0, 4096 bytes)
TCP established hash table entries: 1024 (order: 2, 16384 bytes)
TCP bind hash table entries: 1024 (order: 1, 8192 bytes)
TCP: Hash tables configured (established 1024 bind 1024)
TCP reno registered
NET: Registered protocol family 1
NET: Registered protocol family 22
TCP cubic registered
NET: Registered protocol family 17
Initialized stdio console driver
Console initialized on /dev/tty0
console [tty0] enabled
IRQ 3/console-write: IRQF_DISABLED is not guaranteed on shared IRQs
IRQ 2/console: IRQF_DISABLED is not guaranteed on shared IRQs
IRQ 10/winch: IRQF_DISABLED is not guaranteed on shared IRQs
Kernel panic - not syncing: No init found.  Try passing init= option to kernel.


Modules linked in:
Pid: 1, comm: swapper Not tainted 2.6.32.8
RIP: 0033:[<0000003630a32907>]
RSP: 00007ffff3b091b8  EFLAGS: 00000206
RAX: 0000000000000000 RBX: 00000000000063fc RCX: ffffffffffffffff
RDX: 0000000000000000 RSI: 0000000000000013 RDI: 00000000000063fc
RBP: 00000000000063f8 R08: 0000000000000000 R09: 00007ffff3b0920c
R10: 00007ffff3b08f40 R11: 0000000000000206 R12: 00007f56d0bce6a8
R13: 00007ffff3b093b8 R14: 0000000000000008 R15: 0000000000000001
Call Trace: 
61c27dd8:  [<600115ef>]
61c27df8:  [<600368c2>]
61c27e38:  [<600ef777>]
61c27e58:  [<60060b3d>]
61c27ed8:  [<6000e31a>]
61c27ef8:  [<6000fea9>]
61c27f28:  [<6000e0a9>]
61c27f48:  [<6000117e>]
61c27f68:  [<600188fe>]
61c27f70:  [<600010ac>]
61c27fb8:  [<600188e3>]
61c27fd8:  [<6000f3f3>]


Segmentation fault (core dumped)