Re: 2.6.33: ftrace triggers soft lockup

[Steven Rostedt]

On Fri, 2010-03-12 at 14:20 -0500, Steven Rostedt wrote:
> On Tue, 2010-03-09 at 11:38 +0800, Li Zefan wrote:
> 
> > The segfault is from userspace. This is a segfault I just got:
> > 
> > ftrace_stack_ma[14989]: segfault at fe2e ip 00000000004474c0 sp 00007fffb97e38c0 error 4 in bash[400000+d1000]

I found a reproducer that triggers in seconds:

# echo 1 > options/userstacktrace
# echo 1 > events/lock/enable
# while do :; ls > /dev/null; done

Seems the triggering of the userspace stack trace may be messing with
dynamic linking. Note, this does not happen on all of my boxes. It
happens on fedora 11 but not on RHEL 5.1.

I'm still investigating.

-- Steve


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