From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from nz-out-0506.google.com (nz-out-0506.google.com [64.233.162.235]) by ozlabs.org (Postfix) with ESMTP id 304FBDDE37 for ; Thu, 9 Aug 2007 05:31:29 +1000 (EST) Received: by nz-out-0506.google.com with SMTP id l1so126920nzf for ; Wed, 08 Aug 2007 12:31:28 -0700 (PDT) Message-ID: Date: Wed, 8 Aug 2007 15:31:28 -0400 From: "Anton Kowalski" To: "Wolfgang Reissnegger" Subject: Re: no output to serial console from /init process on ml405 In-Reply-To: <20070808164205.017C3370065@mail150-sin.bigfish.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 References: <20070808153630.AF2D91A88050@mail200-sin.bigfish.com> <20070808164205.017C3370065@mail150-sin.bigfish.com> Cc: linuxppc-embedded@ozlabs.org List-Id: Linux on Embedded PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 8/8/07, Wolfgang Reissnegger wrote: > The thing that points to a problem with init is: > Kernel panic - not syncing: Attempted to kill init! > > What is the string that is supposed to be printed? Maybe the printf > tries to print a string at an invalid address, causing init to crash? > To test that hypothesis, I created a program that loops indefinitely: for (;;) { printf("hello\n"); sleep(1); } return 0; This produces the following output: [ 2.715404] Freeing unused kernel memory: 116k init [ 2.776225] sys_write 1 [ 3.808186] sys_write 1 [ 4.840192] sys_write 1 [ 5.872181] sys_write 1 [ 6.904193] sys_write 1 [ 7.936181] sys_write 1 .... The string "sys_write 1" is from a printk I inserted into sys_write. So init doesn't crash, which suggests that I haven't set up the /dev files correctly. Thanks again. Anton > Also, you can check if you set the option for console on serial output: > Location: > -> Device Drivers > -> Character devices > -> Serial drivers > -> 8250/16550 and compatible serial support (SERIAL_8250 [=y]) > > Cheers, > Wolfgang > > Anton Kowalski wrote: > > Wolfgang, > > > > Thanks, I'll try your suggestion. > > > > It's worth noting that the init executable is calling into the > > kernel. > > > > I put a printk in sys_write, which is on the call path of printf() > > and the output is sent to the console. However, the output of printf > > is not to be seen. This suggests the problem is perhaps in the serial > > device setup? > > > > Anton > > > > On 8/8/07, Wolfgang Reissnegger > > wrote: > >> Hi Anton, > >> > >> it looks as if your init executable is not doing the right thing > >> and for some reason terminates. Maybe your inittab configuration is > >> wrong? Maybe the init executable has been compiled with the wrong > >> options? > >> > >> You can try to copy another executable (e.g. sh, getty) into /init > >> and see if you get any output. If you see anything doing that then > >> most likely there's something wrong with your init executable. > >> > >> Wolfgang > >> > >> Anton Kowalski wrote: > >>> Hi All: > >>> > >>> I'm trying to bring up linux 2.6.21.1 on an ml405 board. The > >>> kernel boots fine but the init process does not produce any > >>> output. The /init program resides in an initramfs file system and > >>> I believe the /dev device files have been set up correctly. > >>> Here's an excerpt from my initramfs specification: > >>> > >>> dir /dev 755 0 0 nod /dev/console 644 0 0 c 5 1 nod /dev/ttyS0 > >>> 644 0 0 c 4 64 > >>> > >>> (I am able to open these files from the init program. I tested > >>> this by sleeping for a specified time on success.) > >>> > >>> Also, printk continues to function after /init terminates and > >>> before the kernel panics. > >>> > >>> Here are the last few lines of the console output: > >>> > >>> [ 0.507478] Serial: 8250/16550 driver $Revision: 1.90 $ 4 > >>> ports, IRQ sharing disabled [ 0.513862] serial8250.0: ttyS0 at > >>> MMIO 0x80201003 (irq = 3) is a 16550A [ 2.927509] RAMDISK > >>> driver initialized: 1 RAM disks of 8192K size 1024 blocksize [ > >>> 3.018391] tun: Universal TUN/TAP device driver, 1.6 [ > >>> 3.079115] tun: (C) 1999-2004 Max Krasnyansky > >>> [ 3.154919] mice: PS/2 mouse device common for all mice [ > >>> 3.218021] TCP cubic registered [ 3.257034] NET: Registered > >>> protocol family 1 [ 3.309405] NET: Registered protocol family > >>> 17 [ 3.363462] Freeing unused kernel memory: 300k init [ > >>> 23.488277] Kernel panic - not syncing: Attempted to kill init! [ > >>> 23.559517] Rebooting in 180 seconds.. > >>> > >>> I'm using the plb uart and the 8250.c driver. (The obp uartlite > >>> driver didn't work so I switched.) The kernel and the init > >>> program were compiled with eldk. > >>> > >>> Any insights into resolving this problem are greatly appreciated. > >>> > >>> > >>> > >>> Anton _______________________________________________ > >>> Linuxppc-embedded mailing list Linuxppc-embedded@ozlabs.org > >>> https://ozlabs.org/mailman/listinfo/linuxppc-embedded > >>> > >> > > > >