** Description changed:
[impact]
calling the glibc function sync_file_range() on a armhf nspawn container
fails.
[test case]
see sample C program from original description below. compile and run
that inside a nspawn container on armhf and it will fail.
+
+ nspawn instructions:
+ sudo apt install debootstrap systemd-container
+ sudo -i
+ debootstrap --arch=armhf bionic ~/bionic-tree/
+ systemd-nspawn -D ~/bionic-tree/
[regression potential]
this only adjusts nspawn to allow the sync_file_range2 syscall which is
used on armhf, so the regression potential is very low. any possible
regressions would likely be when calling sync_file_range().
[other info]
original description:
---
ARM has two sync_file_range syscalls, sync_file_range and
sync_file_range2. The former is apparently not used, and glibc calls the
latter whenever a userspace program calls sync_file_range. I'm guessing
systemd-nspawn doesn't know this, because the follow code consistently
fails in an nspawn container on ARM:
#define _GNU_SOURCE
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <errno.h>
void main()
{
int f = open("/tmp/syncrange.test",O_CREAT|O_RDWR,0666);
int r=sync_file_range(f, 0, 0, 0);
if (r)
perror("sync_file_range");
close(f);
}
This seems to be causing problems specifically for borg(backup) and
postgres:
https://github.com/borgbackup/borg/issues/4710
https://www.postgresql.org/message-id/flat/CA%2BhUKG%2BydOUT4zjxb6QmJWy8U9WbC-q%2BJWV7wLsEY9Df%3Dmw0Mw%40mail.gmail.com#ac8f14897647dc7eae3c7e7cbed36d93
The solution should be to cherrypick
https://github.com/systemd/systemd/pull/13352, I am currently waiting
for systemd to rebuild on a slow ARM box. Any chance of an SRU?
ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: systemd-container 237-3ubuntu10.24
Uname: Linux 4.14.66+ armv7l
NonfreeKernelModules: extcon_usb_gpio
ApportVersion: 2.20.9-0ubuntu7.7
Architecture: armhf
Date: Mon Aug 19 11:10:48 2019
ProcEnviron:
TERM=screen
PATH=(custom, no user)
LANG=en_GB.UTF-8
SHELL=/bin/bash
SourcePackage: systemd
UpgradeStatus: No upgrade log present (probably fresh install)
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https://bugs.launchpad.net/bugs/1840640
Title:
sync_file_range fails in nspawn containers on arm, ppc
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