Re: [Patch net] ipt_CLUSTERIP: fix a race condition of proc file creation

On Wed, Feb 07, 2018 at 09:59:17PM -0800, Cong Wang wrote:

There is a race condition between clusterip_config_entry_put()
and clusterip_config_init(), after we release the spinlock in
clusterip_config_entry_put(), a new proc file with a same IP could
be created immediately since it is already removed from the configs
list, therefore it triggers this warning:

------------[ cut here ]------------
proc_dir_entry 'ipt_CLUSTERIP/172.20.0.170' already registered
WARNING: CPU: 1 PID: 4152 at fs/proc/generic.c:330 proc_register+0x2a4/0x370 fs/proc/generic.c:329
Kernel panic - not syncing: panic_on_warn set ...

As a quick fix, just move the proc_remove() inside the spinlock.

Applied, thanks.