Re: [PATCH v4] net/ncsi: Fix Use-After-Free in NCSI channel and package removal

[Jakub Kicinski <kuba@kernel.org>]

On Sat,  5 Sep 2026 22:59:02 +0800 Wong Boon Jhee wrote:
> In net/ncsi/ncsi-manage.c, ncsi_remove_channel() and
> ncsi_remove_package() remove objects from an RCU-protected linked list
> using list_del_rcu() and immediately free them using kfree().

../net/ncsi/ncsi-manage.c:45:16: warning: unused variable 'flags' [-Wunused-variable]
   45 |         unsigned long flags;
      |                       ^~~~~
../net/ncsi/ncsi-manage.c:906:8: warning: variable 'flags' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
  906 |                         if (ncm->enable)
      |                             ^~~~~~~~~~~
../net/ncsi/ncsi-manage.c:941:37: note: uninitialized use occurs here
  941 |         spin_unlock_irqrestore(&ndp->lock, flags);
      |                                            ^~~~~
../net/ncsi/ncsi-manage.c:906:4: note: remove the 'if' if its condition is always false
  906 |                         if (ncm->enable)
      |                         ^~~~~~~~~~~~~~~~
  907 |                                 goto out_false;
      |                                 ~~~~~~~~~~~~~~
../net/ncsi/ncsi-manage.c:894:21: note: initialize the variable 'flags' to silence this warning
  894 |         unsigned long flags;
      |                            ^
      |                             = 0