linux-next.git/net/batman-adv/bridge_loop_avoidance.c, branch master

batman-adv: drop NULL check for immutable hardif->mesh_iface

2026-06-28T19:58:36+00:00

The batadv_hard_iface->mesh_iface became immutable after the global batadv_hardif_list was removed and batadv_hard_iface only exists when it is assigned to an mesh_iface. This member can never become NULL and thus a check is now unnecessary. Signed-off-by: Sven Eckelmann

batman-adv: bla: update stale kernel-doc

2026-06-05T07:12:08+00:00

The bridge-loop-avoidance code was changed recently to avoid inconsistent state and race condition problems. The kernel-doc addded in these commits (and related code) has various minor deficits which are now resolved. Signed-off-by: Sven Eckelmann

batman-adv: convert cancellation of work items to disable helper

2026-06-05T07:12:06+00:00

With commit 86898fa6b8cd ("workqueue: Implement disable/enable for (delayed) work items"), work queues gained the ability to permanently disallow re-queuing of work items. This is particularly important during object teardown, where a work item must not be re-armed after shutdown begins. Convert all cancel_work_sync() and cancel_delayed_work_sync() call sites to their disable_* equivalents to clarify the intent to prevent re-arming after teardown. Signed-off-by: Sven Eckelmann

batman-adv: bla: annotate lasttime access with READ/WRITE_ONCE

2026-06-03T06:25:11+00:00

The lasttime field for claim, backbone_gw, and loopdetect tracks the jiffies value of the most recent activity and is used to detect timeouts. These accesses are not consistently protected by a lock, so READ_ONCE/WRITE_ONCE must be used to prevent data races caused by compiler optimizations. Cc: stable@kernel.org Fixes: 23721387c409 ("batman-adv: add basic bridge loop avoidance code") Signed-off-by: Sven Eckelmann

batman-adv: replace non-atomic meshif config fields with (READ|WRITE)_ONCE

2026-06-01T12:22:00+00:00

The meshif configuration values are only accessed as plain loads/stores and do not require full atomic_t semantics. Convert these fields to native integer types and replace their users with READ_ONCE()/WRITE_ONCE() to avoid load/store tearing. Signed-off-by: Sven Eckelmann

batman-adv: add missing includes

2026-05-29T19:19:21+00:00

Some of the recent fixes required features from new header files. There is currently no build problem because transitive includes take care of it. But the batman-adv source code tries to avoid the dependency to transitive/implicite includes because it has no control over them and they might get removed at some point. Signed-off-by: Sven Eckelmann

batman-adv: bla: avoid NULL-ptr deref for claim via dropped interface

2026-05-19T08:43:54+00:00

Without rtnl_lock held, a hardif might be retrieved as primary interface of a meshif, but then (while operating on this interface) getting decoupled from the mesh interface. In this case, the meshif still exists but the pointer from the primary hardif to the meshif is set to NULL. The mesh_iface must be checked first to be non-NULL before continuing to send an ARP request using meshif. Cc: stable@kernel.org Fixes: 23721387c409 ("batman-adv: add basic bridge loop avoidance code") Reported-by: Ido Schimmel Reported-by: syzbot+9fdcc9f05a98a540b816@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=9fdcc9f05a98a540b816 Signed-off-by: Sven Eckelmann

batman-adv: bla: avoid double decrement of bla.num_requests

2026-05-19T07:09:34+00:00

The bla.num_requests is increased when no request_sent was in progress. And it is decremented in various places (announcement was received, backbone is purged, periodic work). But the check if the request_sent is actually set to a specific state and the atomic_dec/_inc are not safe because they are not atomic (TOCTOU) and multiple such code portions can run concurrently. At the same time, it is necessary to modify request_sent (state) and bla.num_requests atomically. Otherwise batadv_bla_send_request() might set request_sent to 1 and is interrupted. batadv_handle_announce() can then set request_sent back to 0 and decrement num_requests before batadv_bla_send_request() incremented it. The two operations must therefore be locked. And since state (request_sent) and wait_periods are only accessed inside this lock, they can be converted to simpler datatypes. And to avoid that the bla.num_requests is touched by a parallel running context with a valid backbone_gw reference after batadv_bla_purge_backbone_gw() ran, a third state "stopped" is required to correctly signal that a backbone_gw is in the state of being cleaned up. Cc: stable@kernel.org Fixes: 23721387c409 ("batman-adv: add basic bridge loop avoidance code") Signed-off-by: Sven Eckelmann

batman-adv: bla: fix report_work leak on backbone_gw purge

2026-05-19T07:09:34+00:00

batadv_bla_purge_backbone_gw() removes stale backbone gateway entries, but fails to properly handle their associated report_work: - If report_work is running, the purge must wait for it to finish before freeing the backbone_gw, otherwise the worker may access freed memory (e.g. bat_priv). - If report_work is pending, the purge must cancel it and release the reference held for that pending work item. The previous implementation called hlist_for_each_entry_safe() inside a spin_lock_bh() section, but cancel_work_sync() may sleep and therefore cannot be called from within a spinlock-protected region. Restructure the loop to handle one entry per spinlock critical section: acquire the lock, find the next entry to purge, remove it from the hash list, then release the lock before calling cancel_work_sync() and dropping the hash_entry reference. Repeat until no more entries require purging. Cc: stable@kernel.org Fixes: 23721387c409 ("batman-adv: add basic bridge loop avoidance code") Reviewed-by: Simon Wunderlich Signed-off-by: Sven Eckelmann

batman-adv: bla: put backbone reference on failed claim hash insert

2026-05-08T12:29:02+00:00

When batadv_bla_add_claim() fails to insert a new claim into the hash, it leaked a reference to the backbone_gw for which the claim was intended. Call batadv_backbone_gw_put() on the error path to release the reference and avoid leaking the backbone_gw object. Cc: stable@kernel.org Fixes: 3db0decf1185 ("batman-adv: Fix non-atomic bla_claim::backbone_gw access") Signed-off-by: Sven Eckelmann