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context[2] stuck: (null)
- From: Arkady <arkady dot miasnikov at gmail dot com>
- To: systemtap at sourceware dot org
- Date: Mon, 10 Jul 2017 18:16:02 +0300
- Subject: context[2] stuck: (null)
- Authentication-results: sourceware.org; auth=none
Hi,
I am getting context[2] stuck: (null) error. The cause of error is
likely the "unmanaged" code I have added to the driver. Specifically I
have a shared memory (mmap) in the driver. The failure happens
randomly every 50-200 module restarts The failure happens only on the
multicore CPUs, or happens often enough to be caught.
I tried to force the the wait function with
STAP_OVERRIDE_STUCK_CONTEXT - kernel panics in one of the (probably
random) probes.
While debugging the issue I patched the SystemTap source code - added
an argument to the _stp_runtime_entryfn_get_context(int) like in this
commit https://github.com/larytet/SystemTap/commit/61a284732893fa6f201e07f9f12f5e1820e7c26f
In the function _stp_runtime_context_wait() I print the line in the
source code which called the _stp_runtime_entryfn_get_context()
The "bad" context is enter_be_probe(). I checked the source code of
enter_be_probe() and there is not much there.
I struggle with the problem for some time and I will greatly
appreciate any tip.
Thank you, Arkady.