[PATCH net-next] netconsole: clear cached dev_name on resume-window cleanup

[PATCH net-next] netconsole: clear cached dev_name on resume-window cleanup

[Breno Leitao]

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>
---
 drivers/net/netconsole.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index 606e265cdfd77..a159cb2939811 100644
--- 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
 		 */

---
base-commit: 5855479abc796c3b5d7b2f2ca147d68fc56cae1f
change-id: 20260610-netconsole_fix_more-181a3e6f66ce

Best regards,
-- 
Breno Leitao <leitao@debian.org>

Re: [PATCH net-next] netconsole: clear cached dev_name on resume-window cleanup

[Andre Carvalho]

On Wed, Jun 10, 2026 at 07:26:04AM -0700, Breno Leitao wrote:
> 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>
-- 
Andre Carvalho