Don't trace threads that have interrupts disabled.
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Authored by markj on Jul 31 2017, 1:12 AM.

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jhb
kib

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rS321803: Don't trace running threads that have interrupts disabled.

Summary

The register file of such a thread is in an indeterminate state, so we
shouldn't assume that the frame pointer is valid. In particular, we may
be in the middle of restoring host registers after a vmexit.

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Repository

rS FreeBSD src repository - subversion

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Tests Not Applicable

Event Timeline

markj created this revision.Jul 31 2017, 1:12 AM

Harbormaster completed remote builds in B10756: Diff 31361.Jul 31 2017, 1:12 AM

markj edited the summary of this revision. (Show Details)Jul 31 2017, 1:13 AM

markj added reviewers: jhb, kib.

This is fine, but then you do not need NMI.

This revision is now accepted and ready to land.Jul 31 2017, 7:20 AM

In D11787#244481, @kib wrote:

This is fine, but then you do not need NMI.

We use an NMI to avoid to avoid a deadlock: the case where the target thread holds a spinlock and thus has interrupts disabled, and is blocked on the thread lock held by the stack_save_td_running() caller.

Closed by commit rS321803: Don't trace running threads that have interrupts disabled. (authored by markj). · Explain WhyJul 31 2017, 5:58 PM

This revision was automatically updated to reflect the committed changes.

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head/

sys/

x86/

stack_machdep.c

7 lines

Diff 31383

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head/sys/x86/x86/stack_machdep.c

Don't trace threads that have interrupts disabled.ClosedPublicActions