From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B014B36655B; Tue, 6 Jan 2026 18:00:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767722458; cv=none; b=tKwT02GllBFGev5PSXw7+SjCc10kLN60MMa+Xhz9cG9QddZ0JIG8hrPXhGE2prxRKRBerlsTqN/TtyfGA0MN2sZBz652t4lQ4xeDTdPBsgXJ15c62VWtiVDT487wZ2I6sRYVGVPuKo9TwU48AUoEy0hAV/SCGSU53GEvYxrU8HU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767722458; c=relaxed/simple; bh=WzjStEDWmZsIVK+z8hjjruP5zV+YLeHJ25Xp2bKWnj0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=r1G3p3Vl/p5ByBBlDYZn8dofGCS1/tWizQauHlC6OYWiir3bp3INO3aQfTIY2OGMEO24zF/sM9mQmssThAuF1ynUh0ES51evZbK4KJ81mqV17EsME5F+rjN3cvgerZi9TfZv/d1vMXWS+IGTR/HD4OKtF8SNX9uhITJalmYUHpA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=KEPBsnBs; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="KEPBsnBs" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C2027C116C6; Tue, 6 Jan 2026 18:00:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1767722458; bh=WzjStEDWmZsIVK+z8hjjruP5zV+YLeHJ25Xp2bKWnj0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KEPBsnBsHeVCF4gNF40pMHwFygGcu6JRdixTGuhZ43mJ8x9gxHK7ZmB+94X/CHuJW KjG7SQg0Mn5YrlmQqWoYM+A9rQhbGhAxyf7WOC2hmTv/kc81KdQw0FmuxonxJ0QxA8 hnSAcQr8gh9+c6/zSlNRhM0RE38Qf46i1HN/az4Y= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+b0da83a6c0e2e2bddbd4@syzkaller.appspotmail.com, Jason Gunthorpe Subject: [PATCH 6.18 238/312] RDMA/cm: Fix leaking the multicast GID table reference Date: Tue, 6 Jan 2026 18:05:12 +0100 Message-ID: <20260106170556.461632302@linuxfoundation.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260106170547.832845344@linuxfoundation.org> References: <20260106170547.832845344@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jason Gunthorpe commit 57f3cb6c84159d12ba343574df2115fb18dd83ca upstream. If the CM ID is destroyed while the CM event for multicast creating is still queued the cancel_work_sync() will prevent the work from running which also prevents destroying the ah_attr. This leaks a refcount and triggers a WARN: GID entry ref leak for dev syz1 index 2 ref=573 WARNING: CPU: 1 PID: 655 at drivers/infiniband/core/cache.c:809 release_gid_table drivers/infiniband/core/cache.c:806 [inline] WARNING: CPU: 1 PID: 655 at drivers/infiniband/core/cache.c:809 gid_table_release_one+0x284/0x3cc drivers/infiniband/core/cache.c:886 Destroy the ah_attr after canceling the work, it is safe to call this twice. Link: https://patch.msgid.link/r/0-v1-4285d070a6b2+20a-rdma_mc_gid_leak_syz_jgg@nvidia.com Cc: stable@vger.kernel.org Fixes: fe454dc31e84 ("RDMA/ucma: Fix use-after-free bug in ucma_create_uevent") Reported-by: syzbot+b0da83a6c0e2e2bddbd4@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/68232e7b.050a0220.f2294.09f6.GAE@google.com Signed-off-by: Jason Gunthorpe Signed-off-by: Greg Kroah-Hartman --- drivers/infiniband/core/cma.c | 3 +++ 1 file changed, 3 insertions(+) --- a/drivers/infiniband/core/cma.c +++ b/drivers/infiniband/core/cma.c @@ -2009,6 +2009,7 @@ static void destroy_mc(struct rdma_id_pr ib_sa_free_multicast(mc->sa_mc); if (rdma_protocol_roce(id_priv->id.device, id_priv->id.port_num)) { + struct rdma_cm_event *event = &mc->iboe_join.event; struct rdma_dev_addr *dev_addr = &id_priv->id.route.addr.dev_addr; struct net_device *ndev = NULL; @@ -2031,6 +2032,8 @@ static void destroy_mc(struct rdma_id_pr dev_put(ndev); cancel_work_sync(&mc->iboe_join.work); + if (event->event == RDMA_CM_EVENT_MULTICAST_JOIN) + rdma_destroy_ah_attr(&event->param.ud.ah_attr); } kfree(mc); }