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| author | andrew <andrew@FreeBSD.org> | 2016-05-28 13:05:39 +0000 |
|---|---|---|
| committer | andrew <andrew@FreeBSD.org> | 2016-05-28 13:05:39 +0000 |
| commit | 15f895037c82da771c558cbbda75c3ae7f309e15 (patch) | |
| tree | 6ae0da9974e37e213b350595dc71c70b6aefa396 /lib/libdevdctl/exception.cc | |
| parent | fbe84e555ec89968a32109225d6f5992cca3b5a4 (diff) | |
| download | FreeBSD-src-15f895037c82da771c558cbbda75c3ae7f309e15.zip FreeBSD-src-15f895037c82da771c558cbbda75c3ae7f309e15.tar.gz | |
Don't panic in hwpmc when stopping sampling.
When hwpmc stops sampling it will set the pm_state to something other
than PMC_STATE_RUNNING. This means the following sequence can happen:
CPU 0: Enter the interrupt handler
CPU 0: Set the thread TDP_CALLCHAIN pflag
CPU 1: Stop sampling
CPU 0: Call pmc_process_samples, sampling is stopped so clears ps_nsamples
CPU 0: Finishes interrupt processing with the TDP_CALLCHAIN flag set
CPU 0: Call pmc_capture_user_callchain to capture the user call chain
CPU 0: Find all the pmc sample are free so no call chains need to be captured
CPU 0: KASSERT because of this
This fixes the issue by checking if any of the samples have been stopped
and including this in te KASSERT.
PR: 204273
Reviewed by: bz, gnn
Obtained from: ABT Systems Ltd
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D6581
Diffstat (limited to 'lib/libdevdctl/exception.cc')
0 files changed, 0 insertions, 0 deletions
