The command CHROOT leads to Segmentation fault. A FIX.

[Head_on_a_Stick]

It seems that someone turned off a kernel option, vsyscall=emulate, that chroot relies on.

What on Earth are you blabbering on about?

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empty@E485 ~ % sudo chroot arch
root@E485 / #

Works for me™ without that vsyscall kernel option.

Also:

To fix this, add vsyscall=emulate to the GRUB_CMDLINE_LINUX_DEFAULT variable.

That calls the non-legacy vsyscall option, which is enabled in the stock buster kernel (CONFIG_X86_VSYSCALL_EMULATION). It has *nothing* to do with CONFIG_LEGACY_VSYSCALL_EMULATE — if that option isn't enabled in the kernel then you can't make it work with a kernel parameter.

EDIT: that option appears to be the default: https://github.com/torvalds/linux/blob/ ... .txt#L5449

[Head_on_a_Stick]

This can be hard to debug or figure out if you don't know what you are looking for.

Yeah, you're certainly having problems with it

I have recompiled the kernel with CONFIG_X86_VSYSCALL_EMULATION=y but kept CONFIG_LEGACY_VSYSCALL_NONE=y

Those options are already applied in the stock Debian buster kernel version...

I'd say that turning X86_VSYSCALL_EMULATION back on and keeping the default as LEGACY_VSYSCALL_NONE=y should not hurt security wise

From my buster box:

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empty@E485 ~ % grep 'X86_VSYSCALL\|LEGACY_VSYSCALL' /boot/config-4.19.0-8-amd64
CONFIG_X86_VSYSCALL_EMULATION=y
# CONFIG_LEGACY_VSYSCALL_EMULATE is not set
CONFIG_LEGACY_VSYSCALL_NONE=y
empty@E485 ~ %

And vsyscall=emulate is the default setting, as I've already explained: https://www.kernel.org/doc/html/v4.19/a ... eters.html

[Head_on_a_Stick]

You're just trying to find excuses to post yet more links to that stupid ****** thread, please stop. As a spam-hunter I should probably just move this entire thread and any others in which you're posted that link...

[LE_746F6D617A7A69]

what percentage of Debian users do you think know that they need to add vsyscall=emulate to the kernel command line to get chroot to work?

Actually, the question is:
What percentage of Debian users do you think know that they need to add vsyscall=emulate to the kernel command line to get chroot to work with an ancient version of Debian, where the executables are incompatible with the current version of kernel?

I'm using chroot on a daily basis and it works correctly.
For a while I was running Debian7 32bit on Debian9 64bit in a schroot, because I had no time to move some apps to a new OS version - worked flawlessly.

So, it's just Your special, unique case - and IMO You should change the title of this topic, because chroot command doesn't need any fixes in the kernel.