Comment 40 for bug 1842382

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m4dm4x1337 (m4dm4x1337) wrote : Re: /proc/self/maps paths missing on live session (was vlc won't start; eoan 19.10 ubuntu/lubuntu/kubuntu/xubuntu/ubuntu-mate daily)

The reason why vlc does not start is definitely the overlay filesystem.

How can I know that?

I use Ubuntu on a fully encrypted USB stick with overlay root filesystem (which makes the USB super fast, even faster than ssd).

To enable the overlay root filesystem I use the following initramfs script:
https://gist.github.com/niun/34c945d70753fc9e2cc7

(FYI: the script has a little bug, it can not handle tabulators in fstab, you have to fix that if you want use it for testing, just insert tr "\t" ' ' before grep -v ' / ')

You can disable this script with the kernel command line parameter disable-root-to=yes.

I tested, once with overlay fs and once without overlay fs. vlc starts as long as you do not use overlay fs. But it does not start with enabled overlay fs.

Therefore, the reason must be the overlay filesystem. It can be assumed that thus bug affects all systems that use overlay fs. Not only debian but all distributions. Therefore, I would give this bug a high priority.

In addition, my strace looks a bit different than the strace that has been posted here (see attachment). Last 5 lines:

mmap2(NULL, 26374, PROT_READ, MAP_SHARED, 3, 0) = 0xb7f94000
close(3) = 0
futex(0xb7f2bfe4, FUTEX_WAKE_PRIVATE, 2147483647) = 0
exit_group(1) = ?
+++ exited with 1 +++

I suspect the futex () call fails.

The bug probably has nothing to do with /proc/self/maps.