linux-kernel - Lockdep report for hci_conn_get

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Message-ID: <nycvar.YFH.7.76.2103041405420.12405@cbobk.fhfr.pm>
Date:   Thu, 4 Mar 2021 14:08:34 +0100 (CET)
From:   Jiri Kosina <jikos@...nel.org>
To:     Marcel Holtmann <marcel@...tmann.org>,
        Johan Hedberg <johan.hedberg@...il.com>,
        Luiz Augusto von Dentz <luiz.dentz@...il.com>
cc:     linux-bluetooth@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Lockdep report for hci_conn_get_phy()

Hi,

I am getting the lockdep splat below with current Linus' tree (5.12-rc1). 
I haven't yet analyzed the dependency chain and the code, but sending out 
early in case someone has seen this before and analyzed / fixed it 
already.

Thanks.

 ======================================================
 WARNING: possible circular locking dependency detected
 5.12.0-rc1-00026-g73d464503354 #10 Not tainted
 ------------------------------------------------------
 bluetoothd/1118 is trying to acquire lock:
 ffff8f078383c078 (&hdev->lock){+.+.}-{3:3}, at: hci_conn_get_phy+0x1c/0x150 [bluetooth]
 
 but task is already holding lock:
 ffff8f07e831d920 (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+.}-{0:0}, at: l2cap_sock_getsockopt+0x8b/0x610 

 
 which lock already depends on the new lock.

 
 the existing dependency chain (in reverse order) is:
 
 -> #3 (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+.}-{0:0}:
        lock_sock_nested+0x72/0xa0
        l2cap_sock_ready_cb+0x18/0x70 [bluetooth]
        l2cap_config_rsp+0x27a/0x520 [bluetooth]
        l2cap_sig_channel+0x658/0x1330 [bluetooth]
        l2cap_recv_frame+0x1ba/0x310 [bluetooth]
        hci_rx_work+0x1cc/0x640 [bluetooth]
        process_one_work+0x244/0x5f0
        worker_thread+0x3c/0x380
        kthread+0x13e/0x160
        ret_from_fork+0x22/0x30
 
 -> #2 (&chan->lock#2/1){+.+.}-{3:3}:
        __mutex_lock+0xa3/0xa10
        l2cap_chan_connect+0x33a/0x940 [bluetooth]
        l2cap_sock_connect+0x141/0x2a0 [bluetooth]
        __sys_connect+0x9b/0xc0
        __x64_sys_connect+0x16/0x20
        do_syscall_64+0x33/0x80
        entry_SYSCALL_64_after_hwframe+0x44/0xae
 
 -> #1 (&conn->chan_lock){+.+.}-{3:3}:
        __mutex_lock+0xa3/0xa10
        l2cap_chan_connect+0x322/0x940 [bluetooth]
        l2cap_sock_connect+0x141/0x2a0 [bluetooth]
        __sys_connect+0x9b/0xc0
        __x64_sys_connect+0x16/0x20
        do_syscall_64+0x33/0x80
        entry_SYSCALL_64_after_hwframe+0x44/0xae
 
 -> #0 (&hdev->lock){+.+.}-{3:3}:
        __lock_acquire+0x147a/0x1a50
        lock_acquire+0x277/0x3d0
        __mutex_lock+0xa3/0xa10
        hci_conn_get_phy+0x1c/0x150 [bluetooth]
        l2cap_sock_getsockopt+0x5a9/0x610 [bluetooth]
        __sys_getsockopt+0xcc/0x200
        __x64_sys_getsockopt+0x20/0x30
        do_syscall_64+0x33/0x80
        entry_SYSCALL_64_after_hwframe+0x44/0xae
 
 other info that might help us debug this:

 Chain exists of:
   &hdev->lock --> &chan->lock#2/1 --> sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP
  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP);
                                lock(&chan->lock#2/1);
                                lock(sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP);
   lock(&hdev->lock);
 
  *** DEADLOCK ***

 1 lock held by bluetoothd/1118:
  #0: ffff8f07e831d920 (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+.}-{0:0}, at: l2cap_sock_getsockopt+0x8b/0x610 [bluetooth]
 
 stack backtrace:
 CPU: 3 PID: 1118 Comm: bluetoothd Not tainted 5.12.0-rc1-00026-g73d464503354 #10
 Hardware name: LENOVO 20K5S22R00/20K5S22R00, BIOS R0IET38W (1.16 ) 05/31/2017
 Call Trace:
  dump_stack+0x7f/0xa1
  check_noncircular+0x105/0x120
  ? __lock_acquire+0x147a/0x1a50
  __lock_acquire+0x147a/0x1a50
  lock_acquire+0x277/0x3d0
  ? hci_conn_get_phy+0x1c/0x150 [bluetooth]
  ? __lock_acquire+0x2e1/0x1a50
  ? lock_is_held_type+0xb4/0x120
  ? hci_conn_get_phy+0x1c/0x150 [bluetooth]
  __mutex_lock+0xa3/0xa10
  ? hci_conn_get_phy+0x1c/0x150 [bluetooth]
  ? lock_acquire+0x277/0x3d0
  ? mark_held_locks+0x49/0x70
  ? mark_held_locks+0x49/0x70
  ? hci_conn_get_phy+0x1c/0x150 [bluetooth]
  hci_conn_get_phy+0x1c/0x150 [bluetooth]
  l2cap_sock_getsockopt+0x5a9/0x610 [bluetooth]
  __sys_getsockopt+0xcc/0x200
  __x64_sys_getsockopt+0x20/0x30
  do_syscall_64+0x33/0x80
  entry_SYSCALL_64_after_hwframe+0x44/0xae
 RIP: 0033:0x7fb73df33eee
 Code: 48 8b 0d 85 0f 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 49 89 ca b8 37 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 52 0f 0c 00 f7 d8 64 89 01 48
 RSP: 002b:00007fffcfbbbf08 EFLAGS: 00000203 ORIG_RAX: 0000000000000037
 RAX: ffffffffffffffda RBX: 0000000000000019 RCX: 00007fb73df33eee
 RDX: 000000000000000e RSI: 0000000000000112 RDI: 0000000000000018
 RBP: 0000000000000000 R08: 00007fffcfbbbf44 R09: 0000000000000000
 R10: 00007fffcfbbbf3c R11: 0000000000000203 R12: 0000000000000000
 R13: 0000000000000018 R14: 0000000000000000 R15: 0000556fcefc70d0


-- 
Jiri Kosina
SUSE Labs