+++ /dev/null
-From 3c4475dc947aeadcb12bf779f4ed0cc55100aac8 Mon Sep 17 00:00:00 2001
-From: Sasha Levin <sashal@kernel.org>
-Date: Wed, 29 Sep 2021 11:59:17 +0200
-Subject: net: introduce and use lock_sock_fast_nested()
-
-From: Paolo Abeni <pabeni@redhat.com>
-
-[ Upstream commit 49054556289e8787501630b7c7a9d407da02e296 ]
-
-Syzkaller reported a false positive deadlock involving
-the nl socket lock and the subflow socket lock:
-
-MPTCP: kernel_bind error, err=-98
-============================================
-WARNING: possible recursive locking detected
-5.15.0-rc1-syzkaller #0 Not tainted
---------------------------------------------
-syz-executor998/6520 is trying to acquire lock:
-ffff8880795718a0 (k-sk_lock-AF_INET){+.+.}-{0:0}, at: mptcp_close+0x267/0x7b0 net/mptcp/protocol.c:2738
-
-but task is already holding lock:
-ffff8880787c8c60 (k-sk_lock-AF_INET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1612 [inline]
-ffff8880787c8c60 (k-sk_lock-AF_INET){+.+.}-{0:0}, at: mptcp_close+0x23/0x7b0 net/mptcp/protocol.c:2720
-
-other info that might help us debug this:
- Possible unsafe locking scenario:
-
- CPU0
- ----
- lock(k-sk_lock-AF_INET);
- lock(k-sk_lock-AF_INET);
-
- *** DEADLOCK ***
-
- May be due to missing lock nesting notation
-
-3 locks held by syz-executor998/6520:
- #0: ffffffff8d176c50 (cb_lock){++++}-{3:3}, at: genl_rcv+0x15/0x40 net/netlink/genetlink.c:802
- #1: ffffffff8d176d08 (genl_mutex){+.+.}-{3:3}, at: genl_lock net/netlink/genetlink.c:33 [inline]
- #1: ffffffff8d176d08 (genl_mutex){+.+.}-{3:3}, at: genl_rcv_msg+0x3e0/0x580 net/netlink/genetlink.c:790
- #2: ffff8880787c8c60 (k-sk_lock-AF_INET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1612 [inline]
- #2: ffff8880787c8c60 (k-sk_lock-AF_INET){+.+.}-{0:0}, at: mptcp_close+0x23/0x7b0 net/mptcp/protocol.c:2720
-
-stack backtrace:
-CPU: 1 PID: 6520 Comm: syz-executor998 Not tainted 5.15.0-rc1-syzkaller #0
-Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
-Call Trace:
- __dump_stack lib/dump_stack.c:88 [inline]
- dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
- print_deadlock_bug kernel/locking/lockdep.c:2944 [inline]
- check_deadlock kernel/locking/lockdep.c:2987 [inline]
- validate_chain kernel/locking/lockdep.c:3776 [inline]
- __lock_acquire.cold+0x149/0x3ab kernel/locking/lockdep.c:5015
- lock_acquire kernel/locking/lockdep.c:5625 [inline]
- lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5590
- lock_sock_fast+0x36/0x100 net/core/sock.c:3229
- mptcp_close+0x267/0x7b0 net/mptcp/protocol.c:2738
- inet_release+0x12e/0x280 net/ipv4/af_inet.c:431
- __sock_release net/socket.c:649 [inline]
- sock_release+0x87/0x1b0 net/socket.c:677
- mptcp_pm_nl_create_listen_socket+0x238/0x2c0 net/mptcp/pm_netlink.c:900
- mptcp_nl_cmd_add_addr+0x359/0x930 net/mptcp/pm_netlink.c:1170
- genl_family_rcv_msg_doit+0x228/0x320 net/netlink/genetlink.c:731
- genl_family_rcv_msg net/netlink/genetlink.c:775 [inline]
- genl_rcv_msg+0x328/0x580 net/netlink/genetlink.c:792
- netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2504
- genl_rcv+0x24/0x40 net/netlink/genetlink.c:803
- netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
- netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1340
- netlink_sendmsg+0x86d/0xdb0 net/netlink/af_netlink.c:1929
- sock_sendmsg_nosec net/socket.c:704 [inline]
- sock_sendmsg+0xcf/0x120 net/socket.c:724
- sock_no_sendpage+0x101/0x150 net/core/sock.c:2980
- kernel_sendpage.part.0+0x1a0/0x340 net/socket.c:3504
- kernel_sendpage net/socket.c:3501 [inline]
- sock_sendpage+0xe5/0x140 net/socket.c:1003
- pipe_to_sendpage+0x2ad/0x380 fs/splice.c:364
- splice_from_pipe_feed fs/splice.c:418 [inline]
- __splice_from_pipe+0x43e/0x8a0 fs/splice.c:562
- splice_from_pipe fs/splice.c:597 [inline]
- generic_splice_sendpage+0xd4/0x140 fs/splice.c:746
- do_splice_from fs/splice.c:767 [inline]
- direct_splice_actor+0x110/0x180 fs/splice.c:936
- splice_direct_to_actor+0x34b/0x8c0 fs/splice.c:891
- do_splice_direct+0x1b3/0x280 fs/splice.c:979
- do_sendfile+0xae9/0x1240 fs/read_write.c:1249
- __do_sys_sendfile64 fs/read_write.c:1314 [inline]
- __se_sys_sendfile64 fs/read_write.c:1300 [inline]
- __x64_sys_sendfile64+0x1cc/0x210 fs/read_write.c:1300
- do_syscall_x64 arch/x86/entry/common.c:50 [inline]
- do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
- entry_SYSCALL_64_after_hwframe+0x44/0xae
-RIP: 0033:0x7f215cb69969
-Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 14 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
-RSP: 002b:00007ffc96bb3868 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
-RAX: ffffffffffffffda RBX: 00007f215cbad072 RCX: 00007f215cb69969
-RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000005
-RBP: 0000000000000000 R08: 00007ffc96bb3a08 R09: 00007ffc96bb3a08
-R10: 0000000100000002 R11: 0000000000000246 R12: 00007ffc96bb387c
-R13: 431bde82d7b634db R14: 0000000000000000 R15: 0000000000000000
-
-the problem originates from uncorrect lock annotation in the mptcp
-code and is only visible since commit 2dcb96bacce3 ("net: core: Correct
-the sock::sk_lock.owned lockdep annotations"), but is present since
-the port-based endpoint support initial implementation.
-
-This patch addresses the issue introducing a nested variant of
-lock_sock_fast() and using it in the relevant code path.
-
-Fixes: 1729cf186d8a ("mptcp: create the listening socket for new port")
-Fixes: 2dcb96bacce3 ("net: core: Correct the sock::sk_lock.owned lockdep annotations")
-Suggested-by: Thomas Gleixner <tglx@linutronix.de>
-Reported-and-tested-by: syzbot+1dd53f7a89b299d59eaf@syzkaller.appspotmail.com
-Signed-off-by: Paolo Abeni <pabeni@redhat.com>
-Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
-Signed-off-by: David S. Miller <davem@davemloft.net>
-Signed-off-by: Sasha Levin <sashal@kernel.org>
----
- include/net/sock.h | 31 ++++++++++++++++++++++++++++++-
- net/core/sock.c | 17 ++---------------
- net/mptcp/protocol.c | 2 +-
- 3 files changed, 33 insertions(+), 17 deletions(-)
-
-diff --git a/include/net/sock.h b/include/net/sock.h
-index f23cb259b0e2..980b471b569d 100644
---- a/include/net/sock.h
-+++ b/include/net/sock.h
-@@ -1624,7 +1624,36 @@ void release_sock(struct sock *sk);
- SINGLE_DEPTH_NESTING)
- #define bh_unlock_sock(__sk) spin_unlock(&((__sk)->sk_lock.slock))
-
--bool lock_sock_fast(struct sock *sk) __acquires(&sk->sk_lock.slock);
-+bool __lock_sock_fast(struct sock *sk) __acquires(&sk->sk_lock.slock);
-+
-+/**
-+ * lock_sock_fast - fast version of lock_sock
-+ * @sk: socket
-+ *
-+ * This version should be used for very small section, where process wont block
-+ * return false if fast path is taken:
-+ *
-+ * sk_lock.slock locked, owned = 0, BH disabled
-+ *
-+ * return true if slow path is taken:
-+ *
-+ * sk_lock.slock unlocked, owned = 1, BH enabled
-+ */
-+static inline bool lock_sock_fast(struct sock *sk)
-+{
-+ /* The sk_lock has mutex_lock() semantics here. */
-+ mutex_acquire(&sk->sk_lock.dep_map, 0, 0, _RET_IP_);
-+
-+ return __lock_sock_fast(sk);
-+}
-+
-+/* fast socket lock variant for caller already holding a [different] socket lock */
-+static inline bool lock_sock_fast_nested(struct sock *sk)
-+{
-+ mutex_acquire(&sk->sk_lock.dep_map, SINGLE_DEPTH_NESTING, 0, _RET_IP_);
-+
-+ return __lock_sock_fast(sk);
-+}
-
- /**
- * unlock_sock_fast - complement of lock_sock_fast
-diff --git a/net/core/sock.c b/net/core/sock.c
-index a3eea6e0b30a..1cf0edc79f37 100644
---- a/net/core/sock.c
-+++ b/net/core/sock.c
-@@ -3191,20 +3191,7 @@ void release_sock(struct sock *sk)
- }
- EXPORT_SYMBOL(release_sock);
-
--/**
-- * lock_sock_fast - fast version of lock_sock
-- * @sk: socket
-- *
-- * This version should be used for very small section, where process wont block
-- * return false if fast path is taken:
-- *
-- * sk_lock.slock locked, owned = 0, BH disabled
-- *
-- * return true if slow path is taken:
-- *
-- * sk_lock.slock unlocked, owned = 1, BH enabled
-- */
--bool lock_sock_fast(struct sock *sk) __acquires(&sk->sk_lock.slock)
-+bool __lock_sock_fast(struct sock *sk) __acquires(&sk->sk_lock.slock)
- {
- might_sleep();
- spin_lock_bh(&sk->sk_lock.slock);
-@@ -3226,7 +3213,7 @@ bool lock_sock_fast(struct sock *sk) __acquires(&sk->sk_lock.slock)
- local_bh_enable();
- return true;
- }
--EXPORT_SYMBOL(lock_sock_fast);
-+EXPORT_SYMBOL(__lock_sock_fast);
-
- int sock_gettstamp(struct socket *sock, void __user *userstamp,
- bool timeval, bool time32)
-diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
-index 4d2abdd3cd3b..7d4d40360f77 100644
---- a/net/mptcp/protocol.c
-+++ b/net/mptcp/protocol.c
-@@ -2622,7 +2622,7 @@ static void mptcp_close(struct sock *sk, long timeout)
- inet_csk(sk)->icsk_mtup.probe_timestamp = tcp_jiffies32;
- mptcp_for_each_subflow(mptcp_sk(sk), subflow) {
- struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
-- bool slow = lock_sock_fast(ssk);
-+ bool slow = lock_sock_fast_nested(ssk);
-
- sock_orphan(ssk);
- unlock_sock_fast(ssk, slow);
---
-2.33.0
-
projects / thirdparty / kernel / stable-queue.git / commitdiff
