From nobody Sun Nov 24 05:01:23 2024 Received: from szxga07-in.huawei.com (szxga07-in.huawei.com [45.249.212.35]) (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 982CB38FAD; Thu, 7 Nov 2024 02:17:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.35 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730945835; cv=none; b=nZ1aMoyFGMhEDakepWdPkRklZwxsB5ia6VSkiCceeDePhYWdjoLsqQ4QJts3pRuXwSdRsjpF+iHpPMnijAs/ZbUmh+QcZaRXUcFHtbaAi7lGU18ZnrSfy5siUc/Ae1hRnaeVi77aM0hurHX2ApFt1joXtdDtK8VUiokI3XoXWQ4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730945835; c=relaxed/simple; bh=GrUUUrld2dOYlsaP0IYgGyBkPj2uqFFy1lOlGJihN1E=; h=From:To:CC:Subject:Date:Message-ID:MIME-Version:Content-Type; b=kc/9FEievIyLyBDUmqRFC1q3OrSGM0lCX+f9QXhVQNbGDsUJnQum1mwA3bezqU7zzPjNfRgP5d10nYqi7mVk8hHJj+RBLY6lTL4D0PXwXwu29GVbcqohRm8pq/1cGsmygKJDshaZMH9VPczZAVKZ7Drng07qSA3e/N7d8/1NWws= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.35 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.162.112]) by szxga07-in.huawei.com (SkyGuard) with ESMTP id 4XkQdq1z29z1SDfc; Thu, 7 Nov 2024 10:15:27 +0800 (CST) Received: from kwepemg200005.china.huawei.com (unknown [7.202.181.32]) by mail.maildlp.com (Postfix) with ESMTPS id B71DE140136; Thu, 7 Nov 2024 10:17:09 +0800 (CST) Received: from huawei.com (10.175.101.6) by kwepemg200005.china.huawei.com (7.202.181.32) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Thu, 7 Nov 2024 10:17:08 +0800 From: Wang Liang To: , , , , , , , , , , CC: , , , Subject: [PATCH net] net: fix data-races around sk->sk_forward_alloc Date: Thu, 7 Nov 2024 10:34:05 +0800 Message-ID: <20241107023405.889239-1-wangliang74@huawei.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To kwepemg200005.china.huawei.com (7.202.181.32) Content-Type: text/plain; charset="utf-8" Syzkaller reported this warning: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 16 at net/ipv4/af_inet.c:156 inet_sock_destruct+0x1c5= /0x1e0 Modules linked in: CPU: 0 UID: 0 PID: 16 Comm: ksoftirqd/0 Not tainted 6.12.0-rc5 #26 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01= /2014 RIP: 0010:inet_sock_destruct+0x1c5/0x1e0 Code: 24 12 4c 89 e2 5b 48 c7 c7 98 ec bb 82 41 5c e9 d1 18 17 ff 4c 89 e6= 5b 48 c7 c7 d0 ec bb 82 41 5c e9 bf 18 17 ff 0f 0b eb 83 <0f> 0b eb 97 0f = 0b eb 87 0f 0b e9 68 ff ff ff 66 66 2e 0f 1f 84 00 RSP: 0018:ffffc9000008bd90 EFLAGS: 00010206 RAX: 0000000000000300 RBX: ffff88810b172a90 RCX: 0000000000000007 RDX: 0000000000000002 RSI: 0000000000000300 RDI: ffff88810b172a00 RBP: ffff88810b172a00 R08: ffff888104273c00 R09: 0000000000100007 R10: 0000000000020000 R11: 0000000000000006 R12: ffff88810b172a00 R13: 0000000000000004 R14: 0000000000000000 R15: ffff888237c31f78 FS: 0000000000000000(0000) GS:ffff888237c00000(0000) knlGS:00000000000000= 00 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffc63fecac8 CR3: 000000000342e000 CR4: 00000000000006f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: ? __warn+0x88/0x130 ? inet_sock_destruct+0x1c5/0x1e0 ? report_bug+0x18e/0x1a0 ? handle_bug+0x53/0x90 ? exc_invalid_op+0x18/0x70 ? asm_exc_invalid_op+0x1a/0x20 ? inet_sock_destruct+0x1c5/0x1e0 __sk_destruct+0x2a/0x200 rcu_do_batch+0x1aa/0x530 ? rcu_do_batch+0x13b/0x530 rcu_core+0x159/0x2f0 handle_softirqs+0xd3/0x2b0 ? __pfx_smpboot_thread_fn+0x10/0x10 run_ksoftirqd+0x25/0x30 smpboot_thread_fn+0xdd/0x1d0 kthread+0xd3/0x100 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x34/0x50 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30 ---[ end trace 0000000000000000 ]--- Its possible that two threads call tcp_v6_do_rcv()/sk_forward_alloc_add() concurrently when sk->sk_state =3D=3D TCP_LISTEN with sk->sk_lock unlocked, which triggers a data-race around sk->sk_forward_alloc: tcp_v6_rcv tcp_v6_do_rcv skb_clone_and_charge_r sk_rmem_schedule __sk_mem_schedule sk_forward_alloc_add() skb_set_owner_r sk_mem_charge sk_forward_alloc_add() __kfree_skb skb_release_all skb_release_head_state sock_rfree sk_mem_uncharge sk_forward_alloc_add() sk_mem_reclaim // set local var reclaimable __sk_mem_reclaim sk_forward_alloc_add() In this syzkaller testcase, two threads call tcp_v6_do_rcv() with skb->truesize=3D768, the sk_forward_alloc changes like this: (cpu 1) | (cpu 2) | sk_forward_alloc ... | ... | 0 __sk_mem_schedule() | | +4096 =3D 4096 | __sk_mem_schedule() | +4096 =3D 8192 sk_mem_charge() | | -768 =3D 7424 | sk_mem_charge() | -768 =3D 6656 ... | ... | sk_mem_uncharge() | | +768 =3D 7424 reclaimable=3D7424 | | | sk_mem_uncharge() | +768 =3D 8192 | reclaimable=3D8192 | __sk_mem_reclaim() | | -4096 =3D 4096 | __sk_mem_reclaim() | -8192 =3D -4096 !=3D 0 The skb_clone_and_charge_r() should not be called in tcp_v6_do_rcv() when sk->sk_state is TCP_LISTEN, it happens later in tcp_v6_syn_recv_sock(). Fix the same issue in dccp_v6_do_rcv(). Suggested-by: Eric Dumazet Reviewed-by: Eric Dumazet Fixes: e994b2f0fb92 ("tcp: do not lock listener to process SYN packets") Signed-off-by: Wang Liang --- net/dccp/ipv6.c | 2 +- net/ipv6/tcp_ipv6.c | 4 +--- 2 files changed, 2 insertions(+), 4 deletions(-) diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c index da5dba120bc9..d6649246188d 100644 --- a/net/dccp/ipv6.c +++ b/net/dccp/ipv6.c @@ -618,7 +618,7 @@ static int dccp_v6_do_rcv(struct sock *sk, struct sk_bu= ff *skb) by tcp. Feel free to propose better solution. --ANK (980728) */ - if (np->rxopt.all) + if (np->rxopt.all && sk->sk_state !=3D DCCP_LISTEN) opt_skb =3D skb_clone_and_charge_r(skb, sk); =20 if (sk->sk_state =3D=3D DCCP_OPEN) { /* Fast path */ diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index d71ab4e1efe1..c9de5ef8f267 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -1618,7 +1618,7 @@ int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *sk= b) by tcp. Feel free to propose better solution. --ANK (980728) */ - if (np->rxopt.all) + if (np->rxopt.all && sk->sk_state !=3D TCP_LISTEN) opt_skb =3D skb_clone_and_charge_r(skb, sk); =20 if (sk->sk_state =3D=3D TCP_ESTABLISHED) { /* Fast path */ @@ -1656,8 +1656,6 @@ int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *sk= b) if (reason) goto reset; } - if (opt_skb) - __kfree_skb(opt_skb); return 0; } } else --=20 2.34.1