Back when I was poking around with filesystem fuzzing stuff years back, I noticed something odd:
An EXT filesystem can tell the Linux OS how it should behave "if" the filesystem is corrupt, including triggering a kernel panic. In a world where USB thumb drives exist, this seems... not ideal.
Let's see what happens if we plug such a mass storage device into a fully patched Chromebook in 2024...
Oh.
The man page for tune2fs is pretty clear about this capability.
The person who writes the data to the USB mass storage device can specify that both:
1) The OS that reads the device should panic if the filesystem has an error.
2) The filesystem has an error.
@wdormann ext filesystems also have file ownership, suid capability, etc. The worst of this can be mitigated with mount options (maybe panic on error can too?) but ultimately it's not a suitable fs for external media and should not be auto mounted by anything unless you have a sandboxed FUSE driver for it in place of the kernel one.
@wdormann Indeed, -o errors=continue fixes this. ChromeOS is being bad automounting ext fs on external media without it. Same as mounting without -o nosuid would be a bug.