batman-adv: hold claim backbone gateways by reference

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commit 82d8701b2c upstream.

batadv_bla_add_claim() can replace claim->backbone_gw and drop the old
gateway's last reference while readers still follow the pointer.

The netlink claim dump path dereferences claim->backbone_gw->orig and
takes claim->backbone_gw->crc_lock without pinning the underlying
backbone gateway. batadv_bla_check_claim() still has the same naked
pointer access pattern.

Reuse batadv_bla_claim_get_backbone_gw() in both readers so they operate
on a stable gateway reference until the read-side work is complete.
This keeps the dump and claim-check paths aligned with the lifetime
rules introduced for the other BLA claim readers.

Fixes: 23721387c4 ("batman-adv: add basic bridge loop avoidance code")
Fixes: 04f3f5bf18 ("batman-adv: add B.A.T.M.A.N. Dump BLA claims via netlink")
Cc: stable@vger.kernel.org
Reported-by: Yifan Wu <yifanwucs@gmail.com>
Reported-by: Juefei Pu <tomapufckgml@gmail.com>
Co-developed-by: Yuan Tan <yuantan098@gmail.com>
Signed-off-by: Yuan Tan <yuantan098@gmail.com>
Suggested-by: Xin Liu <bird@lzu.edu.cn>
Signed-off-by: Haoze Xie <royenheart@gmail.com>
Signed-off-by: Ao Zhou <n05ec@lzu.edu.cn>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

...

This commit is contained in:

Haoze Xie 2026-04-13 14:54:07 +02:00 • committed by Greg Kroah-Hartman

parent d7f3d48e08

commit 69d1ce9c72

1 changed files with 18 additions and 9 deletions

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net/batman-adv/bridge_loop_avoidance.c

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