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Message #72971
[Bug 1349028] Re: getitimer returns it_value=0 erroneously
apport information
** Tags added: apport-collected trusty
** Description changed:
According to the 'getitimer()' man page: "The element it_value is set to
the amount of time remaining on the timer, or zero if the timer is
disabled. Similarly, it_interval is set to the reset value."
As such the following Perl program should never exit:
use Time::HiRes;
$SIG{VTALRM} = sub { };
Time::HiRes::setitimer(&Time::HiRes::ITIMER_VIRTUAL, 0.5, 0.4);
while (1) {
my @t = Time::HiRes::getitimer(&Time::HiRes::ITIMER_VIRTUAL);
exit 0 if $t[0] == 0;
}
and on linux-image 3.11.0-18-generic (and all other systems tested) it
loops forever but 3.13.0-32-generic it exits. Have not bisected between
those kernels, nor am I likely to be able to do so soon.
This Perl program shows the timer countdown:
use Time::HiRes;
my $r = [Time::HiRes::gettimeofday()];
sub display {
my ($desc) = @_;
my @t = Time::HiRes::getitimer(&Time::HiRes::ITIMER_VIRTUAL);
my $i = Time::HiRes::tv_interval($r);
printf "%s: elasped=%.8f; time left=%.6f reset time=%.6f\n", $desc,
$i,@t;
}
$SIG{VTALRM} = sub {
display('VTALRM');
exit;
};
Time::HiRes::setitimer(&Time::HiRes::ITIMER_VIRTUAL, 0.5, 0.4);
while (1) {
display('inloop');
}
on other (working) systems it gives:
inloop: elasped=1.65178400; time left=0.001000 reset time=0.401000
inloop: elasped=1.65184200; time left=0.001000 reset time=0.401000
inloop: elasped=1.65186800; time left=0.001000 reset time=0.401000
inloop: elasped=1.65192300; time left=0.001000 reset time=0.401000
inloop: elasped=1.65198100; time left=0.001000 reset time=0.401000
VTALRM: elasped=1.65209800; time left=0.400000 reset time=0.401000
(end of file)
but on the 3.13.0-32-generic or later kernel I get:
inloop: elasped=0.54692100; time left=0.000033 reset time=0.400000
inloop: elasped=0.54692800; time left=0.000026 reset time=0.400000
inloop: elasped=0.54693500; time left=0.000020 reset time=0.400000
inloop: elasped=0.54694100; time left=0.000013 reset time=0.400000
inloop: elasped=0.54694800; time left=0.000007 reset time=0.400000
inloop: elasped=0.54695500; time left=0.000000 reset time=0.400000
inloop: elasped=0.54696200; time left=0.004000 reset time=0.400000
[...]
VTALRM: elasped=0.55013600; time left=0.397062 reset time=0.400000
(end of file)
The reset time also looks dodgy.
Hardware is an Intel Core i7-920 on Asus P6T Deluxe v2 (X58) motherboard
and hasn't changed.
Requested information:
Ubuntu 3.13.0-32.57-generic 3.13.11.4
Description: Ubuntu 14.04.1 LTS
Release: 14.04
# apt-cache policy linux-image-generic
linux-image-generic:
Installed: 3.13.0.32.38
Candidate: 3.13.0.32.38
Version table:
*** 3.13.0.32.38 0
500 http://us.archive.ubuntu.com/ubuntu/ trusty-updates/main amd64 Packages
500 http://us.archive.ubuntu.com/ubuntu/ trusty-security/main amd64 Packages
500 http://us.archive.ubuntu.com/ubuntu/ trusty-proposed/main amd64 Packages
500 http://ppa.launchpad.net/canonical-kernel-team/ppa/ubuntu/ trusty/main amd64 Packages
100 /var/lib/dpkg/status
3.13.0.24.28 0
500 http://us.archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages
+ ---
+ ApportVersion: 2.14.1-0ubuntu3.2
+ Architecture: amd64
+ AudioDevicesInUse:
+ USER PID ACCESS COMMAND
+ /dev/snd/controlC1: tivrusky 3009 F.... pulseaudio
+ /dev/snd/controlC0: tivrusky 3009 F.... pulseaudio
+ DistroRelease: Ubuntu 14.04
+ HibernationDevice: RESUME=UUID=c026abdc-9fee-425c-b5ae-020bf6ea2ad6
+ IwConfig:
+ eth0 no wireless extensions.
+
+ eth1 no wireless extensions.
+
+ lo no wireless extensions.
+ MachineType: System manufacturer System Product Name
+ Package: linux (not installed)
+ ProcFB: 0 radeondrmfb
+ ProcKernelCmdLine: root=UUID=3ea7a4cb-eade-4906-b545-5133d8c14080 ro quiet splash
+ ProcVersionSignature: Ubuntu 3.13.0-32.57-generic 3.13.11.4
+ RelatedPackageVersions:
+ linux-restricted-modules-3.13.0-32-generic N/A
+ linux-backports-modules-3.13.0-32-generic N/A
+ linux-firmware 1.127.5
+ RfKill:
+ 0: hci0: Bluetooth
+ Soft blocked: no
+ Hard blocked: no
+ Tags: trusty
+ Uname: Linux 3.13.0-32-generic x86_64
+ UpgradeStatus: Upgraded to trusty on 2014-06-10 (46 days ago)
+ UserGroups: adm admin cdrom dialout lpadmin mythtv plugdev sambashare vboxusers
+ WifiSyslog: Jul 26 20:23:08 zwei NetworkManager[1174]: <info> Policy set 'Wired connection 2' (eth1) as default for IPv6 routing and DNS.
+ WpaSupplicantLog:
+
+ _MarkForUpload: True
+ dmi.bios.date: 02/04/2009
+ dmi.bios.vendor: American Megatrends Inc.
+ dmi.bios.version: 0203
+ dmi.board.asset.tag: To Be Filled By O.E.M.
+ dmi.board.name: P6T DELUXE V2
+ dmi.board.vendor: ASUSTeK Computer INC.
+ dmi.board.version: Rev 1.xx
+ dmi.chassis.asset.tag: Asset-1234567890
+ dmi.chassis.type: 3
+ dmi.chassis.vendor: Chassis Manufacture
+ dmi.chassis.version: Chassis Version
+ dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr0203:bd02/04/2009:svnSystemmanufacturer:pnSystemProductName:pvrSystemVersion:rvnASUSTeKComputerINC.:rnP6TDELUXEV2:rvrRev1.xx:cvnChassisManufacture:ct3:cvrChassisVersion:
+ dmi.product.name: System Product Name
+ dmi.product.version: System Version
+ dmi.sys.vendor: System manufacturer
** Attachment added: "AlsaInfo.txt"
https://bugs.launchpad.net/bugs/1349028/+attachment/4163587/+files/AlsaInfo.txt
--
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https://bugs.launchpad.net/bugs/1349028
Title:
getitimer returns it_value=0 erroneously
Status in “linux” package in Ubuntu:
Confirmed
Bug description:
According to the 'getitimer()' man page: "The element it_value is set
to the amount of time remaining on the timer, or zero if the timer is
disabled. Similarly, it_interval is set to the reset value."
As such the following Perl program should never exit:
use Time::HiRes;
$SIG{VTALRM} = sub { };
Time::HiRes::setitimer(&Time::HiRes::ITIMER_VIRTUAL, 0.5, 0.4);
while (1) {
my @t = Time::HiRes::getitimer(&Time::HiRes::ITIMER_VIRTUAL);
exit 0 if $t[0] == 0;
}
and on linux-image 3.11.0-18-generic (and all other systems tested) it
loops forever but 3.13.0-32-generic it exits. Have not bisected
between those kernels, nor am I likely to be able to do so soon.
This Perl program shows the timer countdown:
use Time::HiRes;
my $r = [Time::HiRes::gettimeofday()];
sub display {
my ($desc) = @_;
my @t = Time::HiRes::getitimer(&Time::HiRes::ITIMER_VIRTUAL);
my $i = Time::HiRes::tv_interval($r);
printf "%s: elasped=%.8f; time left=%.6f reset time=%.6f\n", $desc,
$i,@t;
}
$SIG{VTALRM} = sub {
display('VTALRM');
exit;
};
Time::HiRes::setitimer(&Time::HiRes::ITIMER_VIRTUAL, 0.5, 0.4);
while (1) {
display('inloop');
}
on other (working) systems it gives:
inloop: elasped=1.65178400; time left=0.001000 reset time=0.401000
inloop: elasped=1.65184200; time left=0.001000 reset time=0.401000
inloop: elasped=1.65186800; time left=0.001000 reset time=0.401000
inloop: elasped=1.65192300; time left=0.001000 reset time=0.401000
inloop: elasped=1.65198100; time left=0.001000 reset time=0.401000
VTALRM: elasped=1.65209800; time left=0.400000 reset time=0.401000
(end of file)
but on the 3.13.0-32-generic or later kernel I get:
inloop: elasped=0.54692100; time left=0.000033 reset time=0.400000
inloop: elasped=0.54692800; time left=0.000026 reset time=0.400000
inloop: elasped=0.54693500; time left=0.000020 reset time=0.400000
inloop: elasped=0.54694100; time left=0.000013 reset time=0.400000
inloop: elasped=0.54694800; time left=0.000007 reset time=0.400000
inloop: elasped=0.54695500; time left=0.000000 reset time=0.400000
inloop: elasped=0.54696200; time left=0.004000 reset time=0.400000
[...]
VTALRM: elasped=0.55013600; time left=0.397062 reset time=0.400000
(end of file)
The reset time also looks dodgy.
Hardware is an Intel Core i7-920 on Asus P6T Deluxe v2 (X58)
motherboard and hasn't changed.
Requested information:
Ubuntu 3.13.0-32.57-generic 3.13.11.4
Description: Ubuntu 14.04.1 LTS
Release: 14.04
# apt-cache policy linux-image-generic
linux-image-generic:
Installed: 3.13.0.32.38
Candidate: 3.13.0.32.38
Version table:
*** 3.13.0.32.38 0
500 http://us.archive.ubuntu.com/ubuntu/ trusty-updates/main amd64 Packages
500 http://us.archive.ubuntu.com/ubuntu/ trusty-security/main amd64 Packages
500 http://us.archive.ubuntu.com/ubuntu/ trusty-proposed/main amd64 Packages
500 http://ppa.launchpad.net/canonical-kernel-team/ppa/ubuntu/ trusty/main amd64 Packages
100 /var/lib/dpkg/status
3.13.0.24.28 0
500 http://us.archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages
---
ApportVersion: 2.14.1-0ubuntu3.2
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC1: tivrusky 3009 F.... pulseaudio
/dev/snd/controlC0: tivrusky 3009 F.... pulseaudio
DistroRelease: Ubuntu 14.04
HibernationDevice: RESUME=UUID=c026abdc-9fee-425c-b5ae-020bf6ea2ad6
IwConfig:
eth0 no wireless extensions.
eth1 no wireless extensions.
lo no wireless extensions.
MachineType: System manufacturer System Product Name
Package: linux (not installed)
ProcFB: 0 radeondrmfb
ProcKernelCmdLine: root=UUID=3ea7a4cb-eade-4906-b545-5133d8c14080 ro quiet splash
ProcVersionSignature: Ubuntu 3.13.0-32.57-generic 3.13.11.4
RelatedPackageVersions:
linux-restricted-modules-3.13.0-32-generic N/A
linux-backports-modules-3.13.0-32-generic N/A
linux-firmware 1.127.5
RfKill:
0: hci0: Bluetooth
Soft blocked: no
Hard blocked: no
Tags: trusty
Uname: Linux 3.13.0-32-generic x86_64
UpgradeStatus: Upgraded to trusty on 2014-06-10 (46 days ago)
UserGroups: adm admin cdrom dialout lpadmin mythtv plugdev sambashare vboxusers
WifiSyslog: Jul 26 20:23:08 zwei NetworkManager[1174]: <info> Policy set 'Wired connection 2' (eth1) as default for IPv6 routing and DNS.
WpaSupplicantLog:
_MarkForUpload: True
dmi.bios.date: 02/04/2009
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 0203
dmi.board.asset.tag: To Be Filled By O.E.M.
dmi.board.name: P6T DELUXE V2
dmi.board.vendor: ASUSTeK Computer INC.
dmi.board.version: Rev 1.xx
dmi.chassis.asset.tag: Asset-1234567890
dmi.chassis.type: 3
dmi.chassis.vendor: Chassis Manufacture
dmi.chassis.version: Chassis Version
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr0203:bd02/04/2009:svnSystemmanufacturer:pnSystemProductName:pvrSystemVersion:rvnASUSTeKComputerINC.:rnP6TDELUXEV2:rvrRev1.xx:cvnChassisManufacture:ct3:cvrChassisVersion:
dmi.product.name: System Product Name
dmi.product.version: System Version
dmi.sys.vendor: System manufacturer
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References
