| Message ID | 20241105080305.717508-1-wangliang74@huawei.com (mailing list archive) |
|---|---|
| State | RFC |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [RFC,net,v2] net: fix data-races around sk->sk_forward_alloc | expand |
On Tue, Nov 5, 2024 at 8:46 AM Wang Liang <wangliang74@huawei.com> wrote: > > 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:0000000000000000 > 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: > <TASK> > ? __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 > </TASK> > ---[ end trace 0000000000000000 ]--- > > Its possible that two threads call tcp_v6_do_rcv()/sk_forward_alloc_add() > concurrently when sk->sk_state == 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=768, the sk_forward_alloc changes like > this: > (cpu 1) | (cpu 2) | sk_forward_alloc > ... | ... | 0 > __sk_mem_schedule() | | +4096 = 4096 > | __sk_mem_schedule() | +4096 = 8192 > sk_mem_charge() | | -768 = 7424 > | sk_mem_charge() | -768 = 6656 > ... | ... | > sk_mem_uncharge() | | +768 = 7424 > reclaimable=7424 | | > | sk_mem_uncharge() | +768 = 8192 > | reclaimable=8192 | > __sk_mem_reclaim() | | -4096 = 4096 > | __sk_mem_reclaim() | -8192 = -4096 != 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 <edumazet@google.com> > Fixes: e994b2f0fb92 ("tcp: do not lock listener to process SYN packets") > Signed-off-by: Wang Liang <wangliang74@huawei.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Thanks.
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_buff *skb) by tcp. Feel free to propose better solution. --ANK (980728) */ - if (np->rxopt.all) + if (np->rxopt.all && sk->sk_state != DCCP_LISTEN) opt_skb = skb_clone_and_charge_r(skb, sk); if (sk->sk_state == 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 *skb) by tcp. Feel free to propose better solution. --ANK (980728) */ - if (np->rxopt.all) + if (np->rxopt.all && sk->sk_state != TCP_LISTEN) opt_skb = skb_clone_and_charge_r(skb, sk); if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */ @@ -1656,8 +1656,6 @@ int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb) if (reason) goto reset; } - if (opt_skb) - __kfree_skb(opt_skb); return 0; } } else
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:0000000000000000 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: <TASK> ? __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 </TASK> ---[ end trace 0000000000000000 ]--- Its possible that two threads call tcp_v6_do_rcv()/sk_forward_alloc_add() concurrently when sk->sk_state == 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=768, the sk_forward_alloc changes like this: (cpu 1) | (cpu 2) | sk_forward_alloc ... | ... | 0 __sk_mem_schedule() | | +4096 = 4096 | __sk_mem_schedule() | +4096 = 8192 sk_mem_charge() | | -768 = 7424 | sk_mem_charge() | -768 = 6656 ... | ... | sk_mem_uncharge() | | +768 = 7424 reclaimable=7424 | | | sk_mem_uncharge() | +768 = 8192 | reclaimable=8192 | __sk_mem_reclaim() | | -4096 = 4096 | __sk_mem_reclaim() | -8192 = -4096 != 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 <edumazet@google.com> Fixes: e994b2f0fb92 ("tcp: do not lock listener to process SYN packets") Signed-off-by: Wang Liang <wangliang74@huawei.com> --- net/dccp/ipv6.c | 2 +- net/ipv6/tcp_ipv6.c | 4 +--- 2 files changed, 2 insertions(+), 4 deletions(-)