IMO, this bug *is* a duplicate of #1215513. The real problem is that the
zram kernel module creates a block device with a bad sector at the end.
When you try to swap on it, anything can happen, from system lockdowns
to program crashes to nothing (e.g., if you have so much RAM you never
get to use the last sector of /dev/zram0).
I posted detailed findings at #55 on the other bug's page.
Kenneth (#51): 'mkswap' run on the entire block device /dev/zram0 DOES
NOT create a visible swap partition for you to see with 'fdisk -l'. The
fact that you don't see a swap partition on it DOES NOT mean /dev/zram0
is not being swapped on. Check this with 'swapon -s' (and disable it if
it's there!) To see this, and also the bad 4KB sector, try this (first
swapoff and rmmod):
$ sudo modprobe zram
$ echo '1024^3' | bc | sudo tee /sys/block/zram0/disksize
1073741824
$ sudo mkswap -c /dev/zram0
one bad page
Setting up swapspace version 1, size = 1048568 KiB
no label, UUID=487d15c0-07ce-46d1-b632-492611e2a13a
$ sudo mkswap /dev/zram0
Setting up swapspace version 1, size = 1048572 KiB
no label, UUID=9fa2c2df-d69c-4282-87ad-7c3219e50832
$ sudo fdisk -l /dev/zram0
Note: sector size is 4096 (not 512)
Disk /dev/zram0: 1073 MB, 1073741824 bytes
255 heads, 63 sectors/track, 16 cylinders, total 262144 sectors
Units = sectors of 1 * 4096 = 4096 bytes
Sector size (logical/physical): 4096 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x00000000
Disk /dev/zram0 doesn't contain a valid partition table
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https://bugs.launchpad.net/bugs/1217189
Title:
Buffer I/O error on device zram0
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