Mdadm Vs Raidcheck

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Hi all!

I don’t religiously follow everything that pops up in the selinux alerts, but now and then I go back and look at some of them.
(I’m on an up to date CentOS-7).

Today I noted an error that seems to occur during a weekly raid check, from /etc/cron.d.

the selinux alert is:

SELinux is preventing /usr/sbin/mdadm from write access on the file /var/log/rear/rear-fcshome.log.lockless.

so I go look at that file and find that it contains, down in the middle of commands run, a series of errors:

2017-02-19 01:30:03 Relax-and-Recover 1.17.2 / Git
2017-02-19 01:30:03 Command line options: /usr/sbin/rear checklayout
2017-02-19 01:30:03 Including /etc/rear/os.conf
2017-02-19 01:30:03 Including conf/Linux-i386.conf
2017-02-19 01:30:03 Including conf/GNU/Linux.conf
2017-02-19 01:30:04 Including /etc/rear/local.conf
2017-02-19 01:30:04 Running ‘init’ stage
2017-02-19 01:30:04 Including init/default/01_set_drlm_env.sh
2017-02-19 01:30:04 Finished running ‘init’ stage in 0 seconds
2017-02-19 01:30:04 Using build area ‘/tmp/rear.oaWHSvnwNFddStm’
2017-02-19 01:30:04 Running checklayout workflow
2017-02-19 01:30:04 Running ‘layout/precompare’ stage
2017-02-19 01:30:04 Including layout/precompare/default/11_check_layout_file.sh
2017-02-19 01:30:04 Finished running ‘layout/precompare’ stage in 0 seconds
2017-02-19 01:30:04 Running ‘layout/save’ stage
2017-02-19 01:30:04 Including layout/save/GNU/Linux/10_create_layout_file.sh
2017-02-19 01:30:04 Creating disk layout
2017-02-19 01:30:04 Preparing layout directory.
2017-02-19 01:30:04 Including layout/save/GNU/Linux/15_save_diskbyid_mappings.sh
2017-02-19 01:30:05 Saved diskbyid_mappings
2017-02-19 01:30:05 Including layout/save/GNU/Linux/20_partition_layout.sh
2017-02-19 01:30:06 Saving disk partitions.
2017-02-19 01:30:08 Including layout/save/GNU/Linux/21_raid_layout.sh
2017-02-19 01:30:08 Saving Software RAID configuration.
/usr/share/rear/layout/save/GNU/Linux/21_raid_layout.sh: line 44: let: sparedevices=-: syntax error: operand expected (error token is “-“)
/usr/share/rear/layout/save/GNU/Linux/21_raid_layout.sh: line 65: [: : integer expression expected
/usr/share/rear/layout/save/GNU/Linux/21_raid_layout.sh: line 44: let: sparedevices=-: syntax error: operand expected (error token is “-“)
/usr/share/rear/layout/save/GNU/Linux/21_raid_layout.sh: line 65: [: : integer expression expected
/usr/share/rear/layout/save/GNU/Linux/21_raid_layout.sh: line 44: let: sparedevices=-: syntax error: operand expected (error token is “-“)
/usr/share/rear/layout/save/GNU/Linux/21_raid_layout.sh: line 65: [: : integer expression expected
/usr/share/rear/layout/save/GNU/Linux/21_raid_layout.sh: line 44: let: sparedevices=-: syntax error: operand expected (error token is “-“)
/usr/share/rear/layout/save/GNU/Linux/21_raid_layout.sh: line 65: [: : integer expression expected
2017-02-19 01:30:09 Including layout/save/GNU/Linux/22_lvm_layout.sh
2017-02-19 01:30:09 Saving LVM layout.
2017-02-19 01:30:11 Including layout/save/GNU/Linux/23_filesystem_layout.sh
2017-02-19 01:30:11 Begin saving filesystem layout
2017-02-19 01:30:11 Saving filesystem layout (using the findmnt command).
2017-02-19 01:30:16 End saving filesystem layout
2017-02-19 01:30:16 Including layout/save/GNU/Linux/24_swaps_layout.sh
2017-02-19 01:30:16 Saving Swap information.
2017-02-19 01:30:16 Including layout/save/GNU/Linux/25_drbd_layout.sh
2017-02-19 01:30:16 Including layout/save/GNU/Linux/26_crypt_layout.sh
2017-02-19 01:30:16 Saving Encrypted volumes.
2017-02-19 01:30:16 Device Mapper name No not found in /dev/mapper.
2017-02-19 01:30:16 Including layout/save/GNU/Linux/27_hpraid_layout.sh
2017-02-19 01:30:16 Including layout/save/GNU/Linux/28_multipath_layout.sh
2017-02-19 01:30:16 Did not find multipath device No in the expected location.
2017-02-19 01:30:16 Including layout/save/default/30_list_dependencies.sh
2017-02-19 01:30:16 Including layout/save/default/31_autoexclude_usb.sh
2017-02-19 01:30:16 Including layout/save/default/31_include_exclude.sh
2017-02-19 01:30:16 Including layout/save/default/32_autoexclude.sh
2017-02-19 01:30:17 Disk /dev/sdb is not used by any mounted filesystem. Excluding.
2017-02-19 01:30:17 Disk /dev/sdc is not used by any mounted filesystem. Excluding.
2017-02-19 01:30:17 Including layout/save/default/33_remove_exclusions.sh
2017-02-19 01:30:17 Including layout/save/GNU/Linux/34_false_blacklisted.sh
2017-02-19 01:30:18 Including layout/save/default/34_generate_mountpoint_device.sh
2017-02-19 01:30:18 Including layout/save/GNU/Linux/35_copy_drbdtab.sh
2017-02-19 01:30:18 Including layout/save/default/40_check_backup_special_files.sh
2017-02-19 01:30:18 Including layout/save/default/45_check_bootloader_files.sh
2017-02-19 01:30:18 Including layout/save/default/45_check_network_files.sh
2017-02-19 01:30:18 Including layout/save/GNU/Linux/50_extract_vgcfg.sh
2017-02-19 01:30:18 Including layout/save/GNU/Linux/51_current_disk_usage.sh
2017-02-19 01:30:19 Including layout/save/default/60_snapshot_files.sh
2017-02-19 01:30:19 Finished running ‘layout/save’ stage in 15 seconds
2017-02-19 01:30:19 Running ‘layout/compare’ stage
2017-02-19 01:30:19 Including layout/compare/default/50_compare_layout.sh
2017-02-19 01:30:19 Disk layout is identical.
2017-02-19 01:30:19 Including layout/compare/default/51_compare_files.sh
2017-02-19 01:30:20 Finished running ‘layout/compare’ stage in 1 seconds
2017-02-19 01:30:20 Finished running checklayout workflow
2017-02-19 01:30:20 Running exit tasks.
2017-02-19 01:30:20 Finished in 18 seconds
2017-02-19 01:30:20 Removing build area /tmp/rear.oaWHSvnwNFddStm
2017-02-19 01:30:20 End of program reached

selinux says it prevent writes to this file. but the file was clearly written to! Is selinux stupid enough to mistake shell errors as a failure to write?

Also, in trying to figure out what those errors mean, I looked at the file specified in the errors,
/usr/share/rear/layout/save/GNU/Linux/21_raid_layout.sh, where I find line 44 and a couple above it read:

ndevices=$( grep “Raid Devices” $TMP_DIR/mdraid | tr -d ” ” | cut -d “:” -f “2”)
totaldevices=$( grep “Total Devices” $TMP_DIR/mdraid | tr -d ” ” | cut -d “:” -f “2”)
let sparedevices=$totaldevices-$ndevices

it appears that “ndevices” and “totaldevices” are both empty (not zero, but empty) because the error report above says “-” isn’t valid, which would happen if those two variables were unpopulated.

At this point I haven’t yet found out where those values come from…
(more to the point, I haven’t yet figured out where TMP_DIR comes from)

If any of you know more than I (I’ve never seen this code before)
I’d appreciate a pointer, but I’ll keep looking too.

In the meantime, my software raid seems to keep chugging along.

thanks in advance!

Fred

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