netconsole: clear cached dev_name on resume-window cleanup

When process_resume_target() catches a device that was unregistered
while the target was off target_list, it calls do_netpoll_cleanup() to
release the reference but leaves the cached np.dev_name in place. The
other cleanup path, netconsole_process_cleanups_core(), already wipes
dev_name for MAC-bound targets because the name was only a cache of the
device that last carried the MAC and may no longer match.

The pattern is the same in both spots, so fold it into a small helper
netcons_release_dev() and route both call sites through it. This makes
the resume-window cleanup consistent with the notifier-driven one so a
later enable does not let netpoll_setup() pick a stale interface by name
when the user bound the target by MAC.

Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Andre Carvalho <asantostc@gmail.com>
Link: https://patch.msgid.link/20260610-netconsole_fix_more-v1-1-a18652c47cef@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index 606e265cdfd77ec75506244da6239fc9dec624f6..a159cb293981114f1b80926a69b36340eb53e234 100644 (file)
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -283,6 +283,13 @@ static bool bound_by_mac(struct netconsole_target *nt)
        return is_valid_ether_addr(nt->np.dev_mac);
 }
 
+static void netcons_release_dev(struct netconsole_target *nt)
+{
+       do_netpoll_cleanup(&nt->np);
+       if (bound_by_mac(nt))
+               memset(&nt->np.dev_name, 0, IFNAMSIZ);
+}
+
 /* Attempts to resume logging to a deactivated target. */
 static void resume_target(struct netconsole_target *nt)
 {
@@ -349,7 +356,7 @@ static void process_resume_target(struct work_struct *work)
        rtnl_lock();
        if (nt->state == STATE_ENABLED && nt->np.dev &&
            nt->np.dev->reg_state != NETREG_REGISTERED) {
-               do_netpoll_cleanup(&nt->np);
+               netcons_release_dev(nt);
                nt->state = STATE_DISABLED;
        }
 
@@ -408,9 +415,7 @@ static void netconsole_process_cleanups_core(void)
        list_for_each_entry_safe(nt, tmp, &target_cleanup_list, list) {
                /* all entries in the cleanup_list needs to be disabled */
                WARN_ON_ONCE(nt->state == STATE_ENABLED);
-               do_netpoll_cleanup(&nt->np);
-               if (bound_by_mac(nt))
-                       memset(&nt->np.dev_name, 0, IFNAMSIZ);
+               netcons_release_dev(nt);
                /* moved the cleaned target to target_list. Need to hold both
                 * locks
                 */