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Hi Phil
Le 18/08/2025 à 11:34, Phil Sutter a écrit :
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Hi Christophe,
On Sun, Aug 17, 2025 at 05:54:27PM +0200, Christophe Leroy wrote:
Le 17/08/2025 à 01:33, Phil Sutter a écrit :
[Vous ne recevez pas souvent de courriers de p...@nwl.cc. D?couvrez pourquoi
ceci est important ? https://aka.ms/LearnAboutSenderIdentification ]
Hi,
I admittedly didn't fully analyze the cause, but on my system a call to:
# insmod /lib/module/$(uname -r)/kernel/net/netfilter/nf_conntrack_ftp.ko
fails with -EEXIST (due to a previous call to 'nfct add helper ftp inet
tcp'). A call to:
# modprobe nf_conntrack_ftp
though returns 0 even though module loading fails. Is there a bug in
modprobe error status handling?
Read the man page :
https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flinux.die.net%2Fman%2F8%2Fmodprobe&data=05%7C02%7Cchristophe.leroy%40csgroup.eu%7C34b49eb3d0544fc683e608ddde3a75b2%7C8b87af7d86474dc78df45f69a2011bb5%7C0%7C0%7C638911064858807750%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=%2F70LV37Zb%2FNeiBV59y9rvkLGh0xsqga08Nl3c5%2BVU5I%3D&reserved=0
In the man page I see:
Normally, modprobe will succeed (and do nothing) if told to
insert a module which is already present or to remove a module which
isn't present.
This is not a case of already inserted module, it is not loaded before
the call to modprobe. It is the module_init callback
nf_conntrack_ftp_init() which returns -EEXIST it received from
nf_conntrack_helpers_register().
Can't user space distinguish the two causes of -EEXIST? Or in other
words, is use of -EEXIST in module_init callbacks problematic?
So if I understand correctly the load fails because it is in conflict
with another module ?
Then I think the error returned by nf_conntrack_helpers_register()
shouldn't be EEXIST but probably EBUSY.
Christophe
