userstacktrace entries coming out as all zeros

[g***@greenrd.org]

If I do

trace-cmd record -T -O userstacktrace -e all -F lxc-execute -n fedora
/bin/bash

the userstacktrace entries all show up as all zeros, like this:

lxc-execute-4020 [001] 4365.325591: user_stack: =>
(00000000)
=> (00000000)
=> (00000000)
=> (00000000)
=> (00000000)
=> (00000000)
=> (00000000)
=> (00000000)

in trace-report.

According to /boot/config-`uname -r`

CONFIG_USER_STACKTRACE_SUPPORT=y

In my last email to the list I was fooled by a kernel config option that
showed as enabled in /boot/config-`uname r`, but actually couldn't have
been enabled because it was incompatible with another config option. But
Kconfig doesn't show this option being incompatible with anything.

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[Steven Rostedt]

Post by g***@greenrd.org
If I do
trace-cmd record -T -O userstacktrace -e all -F lxc-execute -n fedora
/bin/bash
lxc-execute-4020 [001] 4365.325591: user_stack: =>
(00000000)
=> (00000000)
=> (00000000)
=> (00000000)
=> (00000000)
=> (00000000)
=> (00000000)
=> (00000000)
in trace-report.

What kernel version was this? IIRC I fixed a bug in one of the kernel
versions that caused this. I tried it out on my 2.6.33 fedora box and
got the same issue, but on 2.6.38 it seemed to work.

-- Steve


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