netdev - Bluetooth lockdep warning

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>] [day] [month] [year] [list]

Date:	Fri, 29 Jun 2007 14:37:53 +0200
From:	Patrick McHardy <kaber@...sh.net>
To:	marcel@...tmann.org
CC:	Linux Netdev List <netdev@...r.kernel.org>
Subject: Bluetooth lockdep warning

I'm getting this on current -git after adding an obexfs mount
to my fstab:

=============================================
[ INFO: possible recursive locking detected ]
2.6.22-rc6 #2
---------------------------------------------
obexfs/3786 is trying to acquire lock:
 (sk_lock-AF_BLUETOOTH){--..}, at: [<ffffffff88216593>]
l2cap_sock_bind+0x37/0xf3 [l2cap]

but task is already holding lock:
 (sk_lock-AF_BLUETOOTH){--..}, at: [<ffffffff8821f4cc>]
rfcomm_sock_connect+0x47/0xe0 [rfcomm]

other info that might help us debug this:
2 locks held by obexfs/3786:
 #0:  (sk_lock-AF_BLUETOOTH){--..}, at: [<ffffffff8821f4cc>]
rfcomm_sock_connect+0x47/0xe0 [rfc
omm]
 #1:  (rfcomm_mutex){--..}, at: [<ffffffff8123888e>] mutex_lock+0x25/0x2a

stack backtrace:

Call Trace:
 [<ffffffff81044c91>] __lock_acquire+0x162/0xbbe
 [<ffffffff88216593>] :l2cap:l2cap_sock_bind+0x37/0xf3
 [<ffffffff81045769>] lock_acquire+0x7c/0xa0
 [<ffffffff88216593>] :l2cap:l2cap_sock_bind+0x37/0xf3
 [<ffffffff811a0fe8>] lock_sock_nested+0xd6/0xea
 [<ffffffff8104c18c>] module_put+0x4c/0x68
 [<ffffffff88216593>] :l2cap:l2cap_sock_bind+0x37/0xf3
 [<ffffffff8119e2f5>] kernel_bind+0xb/0xd
 [<ffffffff8821cb6f>] :rfcomm:rfcomm_dlc_open+0xc7/0x260
 [<ffffffff81030000>] iomem_open+0x17/0x39
 [<ffffffff8821f525>] :rfcomm:rfcomm_sock_connect+0xa0/0xe0
 [<ffffffff8119edbc>] sys_connect+0x68/0x8e
 [<ffffffff81076fd3>] fd_install+0x5e/0x67
 [<ffffffff81239aa8>] trace_hardirqs_on_thunk+0x35/0x37
 [<ffffffff81044684>] trace_hardirqs_on+0x11c/0x147
 [<ffffffff81239aa8>] trace_hardirqs_on_thunk+0x35/0x37
 [<ffffffff81009cee>] system_call+0x7e/0x83


The warning appears to be bogus (things work fine), the reason
seems to be that the rfcomm socket and the rfcomm l2 socket share
the same lockdep class. Can someone more familiar with that
code please have a look?


-
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html