kevent(2): wrong EVFILT_TIMER timeouts when using NOTE_NSECONDS
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Authored by gbe on Jan 9 2021, 5:42 PM.

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Reviewers

kib
kevans
jmg

Commits

rG8ce9180c09d9: kevent(2): Bugfix for wrong EVFILT_TIMER timeouts
rG6a3ad2d0a7b6: kevent(2): Bugfix for wrong EVFILT_TIMER timeouts

Summary

kevent(2): wrong EVFILT_TIMER timeouts when using NOTE_NSECONDS

From the PR: There is a typo in "timer2sbintime" (sys/kern/kern_event.c) when converting NOTE_NSECONDS to sbintime_t. For the nanosecond part US_TO_SBT instead of NS_TO_SBT is used. This results in weird timeout values.

PR: 252539
Submitted by: Jan Kokemüller <jan dot kokemueller at gmail dot com>

Test Plan

buildworld and a kyua test run

Diff Detail

Repository

rG FreeBSD src repository

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Unit

Tests Not Applicable

Event Timeline

gbe created this revision.Jan 9 2021, 5:42 PM

Herald added a reviewer: jmg. · View Herald TranscriptJan 9 2021, 5:42 PM

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gbe requested review of this revision.Jan 9 2021, 5:42 PM

Harbormaster completed remote builds in B36064: Diff 81959.Jan 9 2021, 5:42 PM

We should also incorporate Jan's reproducer into the test suite, but I can do this after the fact.

Note that the "Submitted by" could be dropped if you recommit locally with git commit --author="Jan Kokemüller <jan.kokemueller@gmail.com>". I haven't seen any particular guidance one way or the other, but IMO the commit metadata attribution is more aesthetically pleasing.

This revision is now accepted and ready to land.Jan 9 2021, 5:47 PM

In D28067#627098, @kevans wrote:

We should also incorporate Jan's reproducer into the test suite, but I can do this after the fact.

Note that the "Submitted by" could be dropped if you recommit locally with git commit --author="Jan Kokemüller <jan.kokemueller@gmail.com>". I haven't seen any particular guidance one way or the other, but IMO the commit metadata attribution is more aesthetically pleasing.

I'll do it once I commit the patch to main. Does your approval implies an "approved by: kevans"? ;-)

kib accepted this revision.Jan 9 2021, 6:50 PM

Indeed

What could be done there, besides tests, is assert that e.g. converting SBT to NS (sbttons()) gives the original value. Or may be this is too naive, it should be orig value within some epsilon.

Closed by commit rG6a3ad2d0a7b6: kevent(2): Bugfix for wrong EVFILT_TIMER timeouts (authored by jan.kokemueller_gmail.com, committed by gbe). · Explain WhyJan 30 2021, 10:14 AM

This revision was automatically updated to reflect the committed changes.

gbe added a commit: rG6a3ad2d0a7b6: kevent(2): Bugfix for wrong EVFILT_TIMER timeouts.

gbe added a commit: rG8ce9180c09d9: kevent(2): Bugfix for wrong EVFILT_TIMER timeouts.Jan 30 2021, 11:41 PM