From: Remi Pommarel Date: Fri, 4 Aug 2023 11:39:36 +0200 Subject: batman-adv: Fix TT global entry leak when client roamed back When a client roamed back to a node before it got time to destroy the pending local entry (i.e. within the same originator interval) the old global one is directly removed from hash table and left as such. But because this entry had an extra reference taken at lookup (i.e using batadv_tt_global_hash_find) there is no way its memory will be reclaimed at any time causing the following memory leak: unreferenced object 0xffff0000073c8000 (size 18560): comm "softirq", pid 0, jiffies 4294907738 (age 228.644s) hex dump (first 32 bytes): 06 31 ac 12 c7 7a 05 00 01 00 00 00 00 00 00 00 .1...z.......... 2c ad be 08 00 80 ff ff 6c b6 be 08 00 80 ff ff ,.......l....... backtrace: [<00000000ee6e0ffa>] kmem_cache_alloc+0x1b4/0x300 [<000000000ff2fdbc>] batadv_tt_global_add+0x700/0xe20 [<00000000443897c7>] _batadv_tt_update_changes+0x21c/0x790 [<000000005dd90463>] batadv_tt_update_changes+0x3c/0x110 [<00000000a2d7fc57>] batadv_tt_tvlv_unicast_handler_v1+0xafc/0xe10 [<0000000011793f2a>] batadv_tvlv_containers_process+0x168/0x2b0 [<00000000b7cbe2ef>] batadv_recv_unicast_tvlv+0xec/0x1f4 [<0000000042aef1d8>] batadv_batman_skb_recv+0x25c/0x3a0 [<00000000bbd8b0a2>] __netif_receive_skb_core.isra.0+0x7a8/0xe90 [<000000004033d428>] __netif_receive_skb_one_core+0x64/0x74 [<000000000f39a009>] __netif_receive_skb+0x48/0xe0 [<00000000f2cd8888>] process_backlog+0x174/0x344 [<00000000507d6564>] __napi_poll+0x58/0x1f4 [<00000000b64ef9eb>] net_rx_action+0x504/0x590 [<00000000056fa5e4>] _stext+0x1b8/0x418 [<00000000878879d6>] run_ksoftirqd+0x74/0xa4 unreferenced object 0xffff00000bae1a80 (size 56): comm "softirq", pid 0, jiffies 4294910888 (age 216.092s) hex dump (first 32 bytes): 00 78 b1 0b 00 00 ff ff 0d 50 00 00 00 00 00 00 .x.......P...... 00 00 00 00 00 00 00 00 50 c8 3c 07 00 00 ff ff ........P.<..... backtrace: [<00000000ee6e0ffa>] kmem_cache_alloc+0x1b4/0x300 [<00000000d9aaa49e>] batadv_tt_global_add+0x53c/0xe20 [<00000000443897c7>] _batadv_tt_update_changes+0x21c/0x790 [<000000005dd90463>] batadv_tt_update_changes+0x3c/0x110 [<00000000a2d7fc57>] batadv_tt_tvlv_unicast_handler_v1+0xafc/0xe10 [<0000000011793f2a>] batadv_tvlv_containers_process+0x168/0x2b0 [<00000000b7cbe2ef>] batadv_recv_unicast_tvlv+0xec/0x1f4 [<0000000042aef1d8>] batadv_batman_skb_recv+0x25c/0x3a0 [<00000000bbd8b0a2>] __netif_receive_skb_core.isra.0+0x7a8/0xe90 [<000000004033d428>] __netif_receive_skb_one_core+0x64/0x74 [<000000000f39a009>] __netif_receive_skb+0x48/0xe0 [<00000000f2cd8888>] process_backlog+0x174/0x344 [<00000000507d6564>] __napi_poll+0x58/0x1f4 [<00000000b64ef9eb>] net_rx_action+0x504/0x590 [<00000000056fa5e4>] _stext+0x1b8/0x418 [<00000000878879d6>] run_ksoftirqd+0x74/0xa4 Releasing the extra reference from batadv_tt_global_hash_find even at roam back when batadv_tt_global_free is called fixes this memory leak. Cc: stable@vger.kernel.org Fixes: 2443ba383c7d ("batman-adv: roaming handling mechanism redesign") Signed-off-by: Remi Pommarel Signed-off-by: Sven Eckelmann Origin: upstream, https://git.open-mesh.org/batman-adv.git/commit/26fce59c70729e07034de966ac5fd2d5c1f2d597 --- a/net/batman-adv/translation-table.c +++ b/net/batman-adv/translation-table.c @@ -774,7 +774,6 @@ check_roaming: if (roamed_back) { batadv_tt_global_free(bat_priv, tt_global, "Roaming canceled"); - tt_global = NULL; } else { /* The global entry has to be marked as ROAMING and * has to be kept for consistency purpose