linux-kernel - RE: printf internals

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1198107085.7740.0.camel@oasis.donpoo.home>
Date:	Wed, 19 Dec 2007 18:31:25 -0500
From:	Scott Russell <catfather@...poo.net>
To:	Siva Prasad <sprasad@...io.net>
Cc:	Clemens Koller <clemens.koller@...gramm.de>,
	David Newall <david@...idnewall.com>,
	linux-kernel@...r.kernel.org
Subject: RE: printf internals


On Wed, 2007-12-19 at 14:33 -0800, Siva Prasad wrote:
> Thank you very much for your response Clemens.
> 
> I tried strace on a regular system. It does not show which tty, etc., as it uses the stdout (fd = 1) and write(1, ...) to it.
> 
> This is not a student project. I am trying to build my own kernel and ramdisk. Kernel boots fine to a point where it starts accessing ramdisk and executes init scripts. From there on nothing gets printed. I did some debugging and found that prints of user land programs are not coming to the serial console, while kernel prints are working fine. I found all the programs getting executed, by placing a printk in execve routine and printing the arguments.
> 
> So, I wanted to trace down the path from user program to the kernel and see why it is not printing messages from user program. I placed a printk in drivers/char/tty_io.c:tty_write() and it is not getting called from my file system. I tried the same thing on my good system (say regular PC) and it works as expected.
> 
> Any clues that can help debug this issue is highly appreciated.
> How can I get access to the same printf string inside kernel.

This sounds like you're printing out the serial console instead.

-- 
Scott <catfather@...poo.net>
AIM: BlueCame1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/