From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794590536; b=lnLtEo+W1OWXivc/Y27JUndCpDdKFDICDgRnuBc0PZIJ5Rg5SJvzHyGlQvJF898OL3ks 19Ff90JywKwMJskKs8FpiApWkufQm80JPG0sI9CEZOk+3LAaAfBFyxNc4JY9xZcR6+SYz fwEHvv11JaWqckISF83wO07BmM0WXjxahkGXdBL8fxl36QfgoTALODRTjC+sUHSizAUUp Jr1DqVhXviwfB2XoS4WrN4IxBKcBDVFbLuVAdRJLAOYFXqy51xztEHwntdfmEP/dqN492 yxAuLgkS+olEuxeqD5ff4qORnPOJJdfQTMDxLRJDj7vUDmqUVR9YXe8ozJle/PD7HPw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794590536; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=nNDCyJtmUpCeVVtHncTMtH8Bp7+7ntvvuFQKMrBhUmo=; b=wNpuJfm4puWrf44ogDYtIPCtjWn0IKT6iil/OZu+oCgiZ93XhLh+S9rxkQyXXKKdSjK0 OAd9qtmfmSX/roRR7Etc+mSn92lFPO3WcJ/UnabY9V+a5Vj0IcxcqjC9cPrTW3aizhDKC Y7XND3x1bk7xkhA8X4SEVhhu/EB2XoJJkKfMWEBsQne6TLj8xycdw5s/dNHKaUeZMu8IE LKpsoff5hYjhjVFnMyugFr40XpQVd6fUtHDizizqu2PGuMfMrmi+DXN0N5/bXd5yOFhPc J41rrJcQ5kZc9X3HsrrM5NUKFkFxUFnBZFKL4CG0ZVjBehxp+mIk171qIxLZH4sZnTA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=yt2fDD9a; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2CB55606B365; Fri, 13 Nov 2026 17:22:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=yt2fDD9a Received: by smtp.kernel.org (Postfix) with ESMTPSA id CC83F1F000C4; Fri, 13 Nov 2026 17:22:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794590536; bh=nNDCyJtmUpCeVVtHncTMtH8Bp7+7ntvvuFQKMrBhUmo=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=yt2fDD9acCgSh0WNK9r4iw/j8j6OwXAxzaGhKcHl69shzIK2rA/JCwAIKcBArnaut hQTeu8hE+5TiCwJo5wsKC3xLYSbGCuFZ1YEU83HfG39rCXWxfFLTcoSLEwavSojXsH spZ++tOL1l2S4MLZVwCL7U61vqv1pH3wYQPWNcNE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Sashiko , Sven Eckelmann , Sasha Levin Subject: [PATCH 6.18 477/686] batman-adv: tt: dont drop local events queued during TVLV update Date: Fri, 13 Nov 2026 10:50:10 -0500 Message-ID: <20261113153837.100624011@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261113153820.902362109@linuxfoundation.org> References: <20261113153820.902362109@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sven Eckelmann commit ed7a0dfdd370acb48be7a281df732c1bebcc7f1d upstream. batadv_tt_tvlv_container_update() read the number of local changes without holding changes_list_lock. batadv_tt_local_event() is not serialized by the commit_lock and can queue new events before the changes_list is flushed: CPU0 CPU1 batadv_tt_tvlv_container_update() num = ...local_changes; batadv_tt_local_event() list_add_tail(...); ...local_changes++; spin_lock_bh(&...changes_list_lock); /* only num events copied but all freed */ The additional events were freed without ever being sent. Other nodes will only notice this via a CRC mismatch and must request the full table. The number of changes and the changes_list must therefore be taken atomically. Events queued afterwards then stay in the tt.changes_list for the next TT round. The changes can no longer be kept for the next round when the TVLV buffer allocation fails. But they would be sent with a skipped TTVN anyway, so the other nodes have to request the full table in this case either way. The last changeset is only dropped in this case when the TTVN was incremented. Without new changes, it still describes the current TTVN. Previously, the unconsumed changes caused a retry of the TVLV container update in the next commit round. Since the changes are now consumed, the next round would only take the path without changes and wait for BATADV_TT_OGM_APPEND_MAX rounds before updating the container again. Until then, the outdated container with the previous TTVN would still be announced. The ogm_append_cnt is therefore reset on failure to retry the update in the next OGM interval. This doesn't make the CRC consistent with the announced changeset. The local table modifications are still not serialized with the commit and batadv_tt_local_transition_new() can still make a client part of the CRC for which the event is only part of the next TT round. Such an inconsistency is detected by the CRC check of the other nodes and solved via a full table request. Cc: stable@vger.kernel.org Reported-by: Sashiko Closes: https://sashiko.dev/#/bug/linux-fc286ddd-5bed-4683-b842-ee7a307eeb19 Fixes: a73105b8d4c7 ("batman-adv: improved client announcement mechanism") [ Context ] Signed-off-by: Sven Eckelmann Signed-off-by: Sasha Levin --- net/batman-adv/translation-table.c | 61 +++++++++++++++++++++++------- 1 file changed, 48 insertions(+), 13 deletions(-) diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c index e7242706e3345..dfec5cce5fe50 100644 --- a/net/batman-adv/translation-table.c +++ b/net/batman-adv/translation-table.c @@ -978,20 +978,22 @@ batadv_tt_prepare_tvlv_local_data(struct batadv_priv *bat_priv, * batadv_tt_tvlv_container_update() - update the translation table tvlv * container after local tt changes have been committed * @bat_priv: the bat priv with all the mesh interface information + * @changes_list: list of committed changes which will be consumed + * @tt_diff_entries_num: number of entries in @changes_list */ -static void batadv_tt_tvlv_container_update(struct batadv_priv *bat_priv) +static void batadv_tt_tvlv_container_update(struct batadv_priv *bat_priv, + struct list_head *changes_list, + int tt_diff_entries_num) { struct batadv_tt_change_node *entry, *safe; struct batadv_tvlv_tt_data *tt_data; struct batadv_tvlv_tt_change *tt_change; int tt_diff_len, tt_change_len = 0; - int tt_diff_entries_num = 0; int tt_diff_entries_count = 0; bool drop_changes = false; size_t tt_extra_len = 0; u16 tvlv_len; - tt_diff_entries_num = READ_ONCE(bat_priv->tt.local_changes); tt_diff_len = batadv_tt_len(tt_diff_entries_num); /* if we have too many changes for one packet don't send any @@ -1009,19 +1011,39 @@ static void batadv_tt_tvlv_container_update(struct batadv_priv *bat_priv) tvlv_len = batadv_tt_prepare_tvlv_local_data(bat_priv, &tt_data, &tt_change, &tt_diff_len); - if (!tvlv_len) + if (!tvlv_len) { + /* the changes are lost and the other nodes have to request the + * full table. Don't answer TT requests for the new TTVN with + * the stale changeset of the previous TTVN. Without changes, the + * TTVN was not incremented and the last changeset is still valid + */ + if (drop_changes || tt_diff_entries_num > 0) { + list_for_each_entry_safe(entry, safe, changes_list, + list) { + list_del(&entry->list); + kmem_cache_free(batadv_tt_change_cache, entry); + } + + spin_lock_bh(&bat_priv->tt.last_changeset_lock); + kfree(bat_priv->tt.last_changeset); + bat_priv->tt.last_changeset = NULL; + bat_priv->tt.last_changeset_len = 0; + spin_unlock_bh(&bat_priv->tt.last_changeset_lock); + } + + /* announce the already committed TTVN in the next OGM interval + * instead of waiting for BATADV_TT_OGM_APPEND_MAX idle rounds + */ + atomic_set(&bat_priv->tt.ogm_append_cnt, 0); return; + } tt_data->flags = BATADV_TT_OGM_DIFF; if (!drop_changes && tt_diff_len == 0) goto container_register; - spin_lock_bh(&bat_priv->tt.changes_list_lock); - WRITE_ONCE(bat_priv->tt.local_changes, 0); - - list_for_each_entry_safe(entry, safe, &bat_priv->tt.changes_list, - list) { + list_for_each_entry_safe(entry, safe, changes_list, list) { if (tt_diff_entries_count < tt_diff_entries_num) { memcpy(tt_change + tt_diff_entries_count, &entry->change, @@ -1031,7 +1053,6 @@ static void batadv_tt_tvlv_container_update(struct batadv_priv *bat_priv) list_del(&entry->list); kmem_cache_free(batadv_tt_change_cache, entry); } - spin_unlock_bh(&bat_priv->tt.changes_list_lock); tt_extra_len = batadv_tt_len(tt_diff_entries_num - tt_diff_entries_count); @@ -3695,11 +3716,25 @@ static void batadv_tt_local_purge_pending_clients(struct batadv_priv *bat_priv) */ static void batadv_tt_local_commit_changes_nolock(struct batadv_priv *bat_priv) { + LIST_HEAD(changes_list); + int changes_num; + lockdep_assert_held(&bat_priv->tt.commit_lock); - if (READ_ONCE(bat_priv->tt.local_changes) == 0) { + /* atomically get the list of changes. The TTVN decision and the + * announced changeset must cover the same events. Events queued + * afterwards stay in the tt.changes_list for the next TT round + */ + spin_lock_bh(&bat_priv->tt.changes_list_lock); + list_splice_init(&bat_priv->tt.changes_list, &changes_list); + changes_num = READ_ONCE(bat_priv->tt.local_changes); + WRITE_ONCE(bat_priv->tt.local_changes, 0); + spin_unlock_bh(&bat_priv->tt.changes_list_lock); + + if (changes_num == 0) { if (!batadv_atomic_dec_not_zero(&bat_priv->tt.ogm_append_cnt)) - batadv_tt_tvlv_container_update(bat_priv); + batadv_tt_tvlv_container_update(bat_priv, &changes_list, + changes_num); return; } @@ -3716,7 +3751,7 @@ static void batadv_tt_local_commit_changes_nolock(struct batadv_priv *bat_priv) /* reset the sending counter */ atomic_set(&bat_priv->tt.ogm_append_cnt, BATADV_TT_OGM_APPEND_MAX); - batadv_tt_tvlv_container_update(bat_priv); + batadv_tt_tvlv_container_update(bat_priv, &changes_list, changes_num); } /** -- 2.53.0