[PATCH] libkmod-module: fix return code in error path

[PATCH] libkmod-module: fix return code in error path

[Lucas De Marchi]

From: Lucas De Marchi <lucas.demarchi@intel.com>

ENOSYS is the wrong errno to return when we don't find a module in
kmod_module_insert_module(). Why is it there in the first place?  This
goes back to kmod v1 when we couldn't load modules by names, but we
should give a path instead.

708624a ("ELF: initial support for modinfo and strip of modversions and
vermagic.") changed that so we do a lazy-search by the module path in
this function. Later  f304afe ("Change error message to reflect
reality") fixed the log message but the return coded remained the same.
---

CC'ing here people from systemd who were bitten by this bug in kmod:
https://github.com/systemd/systemd/pull/166

I'm not sure about changing the return code since it was returning ENOSYS since
v1 :-/.  However maybe the best thing to do is just treat it as a bug and let
the patch to be backported by distros that want it.  Thoughts?


 libkmod/libkmod-module.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libkmod/libkmod-module.c b/libkmod/libkmod-module.c
index 366308f..50b2ff9 100644
--- a/libkmod/libkmod-module.c
+++ b/libkmod/libkmod-module.c
@@ -830,7 +830,7 @@ KMOD_EXPORT int kmod_module_insert_module(struct kmod_module *mod,
 	path = kmod_module_get_path(mod);
 	if (path == NULL) {
 		ERR(mod->ctx, "could not find module by name='%s'\n", mod->name);
-		return -ENOSYS;
+		return -ENOENT;
 	}
 
 	mod->file = kmod_file_open(mod->ctx, path);
-- 
2.4.3

Re: [PATCH] libkmod-module: fix return code in error path

[David Herrmann]

Hi

On Sat, Jun 13, 2015 at 11:45 PM, Lucas De Marchi
<lucas.de.marchi@gmail.com> wrote:
> From: Lucas De Marchi <lucas.demarchi@intel.com>
>
> ENOSYS is the wrong errno to return when we don't find a module in
> kmod_module_insert_module(). Why is it there in the first place?  This
> goes back to kmod v1 when we couldn't load modules by names, but we
> should give a path instead.
>
> 708624a ("ELF: initial support for modinfo and strip of modversions and
> vermagic.") changed that so we do a lazy-search by the module path in
> this function. Later  f304afe ("Change error message to reflect
> reality") fixed the log message but the return coded remained the same.
> ---
>
> CC'ing here people from systemd who were bitten by this bug in kmod:
> https://github.com/systemd/systemd/pull/166
>
> I'm not sure about changing the return code since it was returning ENOSYS since
> v1 :-/.  However maybe the best thing to do is just treat it as a bug and let
> the patch to be backported by distros that want it.  Thoughts?

Looks all good to me. Treating this as a bugfix is probably the best
thing to do. I'll revert the systemd patch once this is pushed.

Thanks
David

>
>  libkmod/libkmod-module.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/libkmod/libkmod-module.c b/libkmod/libkmod-module.c
> index 366308f..50b2ff9 100644
> --- a/libkmod/libkmod-module.c
> +++ b/libkmod/libkmod-module.c
> @@ -830,7 +830,7 @@ KMOD_EXPORT int kmod_module_insert_module(struct kmod_module *mod,
>         path = kmod_module_get_path(mod);
>         if (path == NULL) {
>                 ERR(mod->ctx, "could not find module by name='%s'\n", mod->name);
> -               return -ENOSYS;
> +               return -ENOENT;
>         }
>
>         mod->file = kmod_file_open(mod->ctx, path);
> --
> 2.4.3
>

Re: [PATCH] libkmod-module: fix return code in error path

[Lucas De Marchi]

On Sun, Jun 14, 2015 at 7:55 AM, David Herrmann <dh.herrmann@gmail.com> wrote:
> Hi
>
> On Sat, Jun 13, 2015 at 11:45 PM, Lucas De Marchi
> <lucas.de.marchi@gmail.com> wrote:
>> From: Lucas De Marchi <lucas.demarchi@intel.com>
>>
>> ENOSYS is the wrong errno to return when we don't find a module in
>> kmod_module_insert_module(). Why is it there in the first place?  This
>> goes back to kmod v1 when we couldn't load modules by names, but we
>> should give a path instead.
>>
>> 708624a ("ELF: initial support for modinfo and strip of modversions and
>> vermagic.") changed that so we do a lazy-search by the module path in
>> this function. Later  f304afe ("Change error message to reflect
>> reality") fixed the log message but the return coded remained the same.
>> ---
>>
>> CC'ing here people from systemd who were bitten by this bug in kmod:
>> https://github.com/systemd/systemd/pull/166
>>
>> I'm not sure about changing the return code since it was returning ENOSYS since
>> v1 :-/.  However maybe the best thing to do is just treat it as a bug and let
>> the patch to be backported by distros that want it.  Thoughts?
>
> Looks all good to me. Treating this as a bugfix is probably the best
> thing to do. I'll revert the systemd patch once this is pushed.

Applied.  The next release will take a while but I do recommend all
distros to cherry-pick this patch.


thanks.

-- 
Lucas De Marchi