Re: 2.4.23-pre9 ide+XFree+ptrace=Complete hang

[Linus Torvalds]

On Wed, 12 Nov 2003, Maciej Zenczykowski wrote:
> 
> Well I got a hold of the necessary cabling and I'm sorry to report that
> there is absolutely nothing on the serial console - I get the boot
> messages, etc. fine, the last message before crashing is 'Loglevel set to
> 9' [invoked by hand via Alt+SysRq+9], after which I crash it with 'strace
> ls -lR /' (as a normal user) and nothing else shows up, no oops no nada.  

Ok. The nice thing about getting a serial console is that now you could 
try the NMI watchdog - just boot up with "nmi_watchdog=1" on the kernel 
command line (or "=2" - see Documentation/nmi_watchdog.txt for more 
information on it). 

That won't necessarily see the problem either, especially if it's a total 
hardware lockup brought on by X poking registers in unfortunate ways, but 
if it's a pure kernel lockup with interrupts disabled, it can help.

		Linus

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