TL;DR: Bug happened again, workaround works.
Have not tried dd yet, but whenever the bug happen I open a shell, use
bash Ctrl-R to find the one-liner below, press enter and expect that it
works around the bug.
for PROCESSLINE in $( grep -a ^script /proc/*/cmdline -l ) ; do cd
$(dirname $PROCESSLINE) ; pwd ; ls -al fd ; strace head -n 1 fd/4 & echo
voila ; done
It did.
Here's a relevant part of strace output:
open("fd/4", O_RDONLY) = 3
read(3, "\n", 8192) = 1
lseek(3, 0, SEEK_CUR) = -1 ESPIPE (Illegal seek)
fstat(3, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 9), ...}) = 0
fstat(1, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 12), ...}) = 0
write(1, "\n", 1
) = 1
close(3) = 0
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You received this bug notification because you are a member of Ubuntu
Touch seeded packages, which is subscribed to util-linux in Ubuntu.
https://bugs.launchpad.net/bugs/1558236
Title:
/usr/bin/script freezes and eats all CPU, has to be killed, which
kills shell and programs inside
Status in util-linux package in Ubuntu:
New
Bug description:
# Context
I've been using /usr/bin/script quite a lot for about 4 years (since
about Ubuntu 12.04, maybe before). It always worked without problem.
I'm using several script instance most of the time, in several
terminals.
Reproducible: randomly, once every few days.
Problem happens since Ubuntu 16.04. Never seen before (12.04 12.10
13.04 13.10 14.04 14.10 15.04 15.10).
# Expected
Continued operation, terminal running programs normally, little CPU
used.
# Observed
Suddenly, terminal freezes.
Other tabs of same terminal window not affected.
Top shows script consumes 100% CPU.
Strace shows an endless stream of this line:
poll([{fd=4, events=POLLIN}], 1, 10) = 1 ([{fd=4, revents=POLLIN}])
/proc/*/fd shows what file descriptor it is:
total 0
dr-x------ 2 stephane stephane 0 mars 16 20:03 .
dr-xr-xr-x 9 stephane stephane 0 mars 16 20:03 ..
lrwx------ 1 stephane stephane 64 mars 16 20:15 0 -> /dev/pts/17 (deleted)
lrwx------ 1 stephane stephane 64 mars 16 20:15 1 -> /dev/pts/17 (deleted)
lrwx------ 1 stephane stephane 64 mars 16 20:03 2 -> /dev/pts/17 (deleted)
lrwx------ 1 stephane stephane 64 mars 16 20:15 3 -> /dev/ptmx
lrwx------ 1 stephane stephane 64 mars 16 20:15 4 -> /dev/pts/21
lrwx------ 1 stephane stephane 64 mars 16 20:15 5 -> anon_inode:[signalfd]
l-wx------ 1 stephane stephane 64 mars 16 20:15 6 -> /somewhere/mylogfile.txt
l-wx------ 1 stephane stephane 64 mars 16 20:15 7 ->
/somewhere/mylogfile_timings.txt
What can we do?
ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: bsdutils 1:2.27.1-6ubuntu1
ProcVersionSignature: Ubuntu 4.4.0-13.29-generic 4.4.5
Uname: Linux 4.4.0-13-generic x86_64
ApportVersion: 2.20-0ubuntu3
Architecture: amd64
CurrentDesktop: XFCE
Date: Wed Mar 16 20:04:02 2016
ExecutablePath: /usr/bin/script
InstallationDate: Installed on 2016-02-03 (41 days ago)
InstallationMedia: Xubuntu 16.04 LTS "Xenial Xerus" - Alpha amd64 (20160203)
SourcePackage: util-linux
UpgradeStatus: No upgrade log present (probably fresh install)
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