Re: [PATCH] module: Add more error message for failed kernel module loading

From: Jessica Yu
Date: Wed Sep 02 2020 - 05:40:25 EST


+++ Qu Wenruo [02/09/20 14:46 +0800]:
When kernel module loading failed, user space only get one of the
following error messages:

- ENOEXEC
This is the most confusing one. From corrupted ELF header to bad
WRITE|EXEC flags check introduced by in module_enforce_rwx_sections()
all returns this error number.

- EPERM
This is for blacklisted modules. But mod doesn't do extra explain
on this error either.

- ENOMEM
The only error which needs no explain.

This means, if a user got "Exec format error" from modprobe, it provides
no meaningful way for the user to debug, and will take extra time
communicating to get extra info.

So this patch will add extra error messages for -ENOEXEC and -EPERM
errors, allowing user to do better debugging and reporting.

Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
Reviewed-by: Lucas De Marchi <lucas.demarchi@xxxxxxxxx>

Applied, thanks.

Jessica