[ INFO: possible recursive locking detected ] systemd-logind/651 is trying to acquire lock:

[Lennart Poettering]

On Fri, 15.07.11 12:11, Lucas (macachuto at gmail.com) wrote:

> Dear All.
> 
> Just updated and got the following in dmesg:

This is a kernel bug, please file a bug in rhbz against the kernel and
include this log fragment. Thanks!

> [   37.653381] =============================================
> [   37.654015] [ INFO: possible recursive locking detected ]
> [   37.654015] 3.0-0.rc7.git0.1.fc16.i686 #1
> [   37.654015] ---------------------------------------------
> [   37.654015] systemd-logind/651 is trying to acquire lock:
> [   37.654015]  (&ep->mtx){+.+.+.}, at: [<c05285f1>] ep_scan_ready_list+0x32/0x154
> [   37.654015]
> [   37.654015] but task is already holding lock:
> [   37.654015]  (&ep->mtx){+.+.+.}, at: [<c0528a90>] sys_epoll_ctl+0x103/0x481
> [   37.654015]
> [   37.654015] other info that might help us debug this:
> [   37.654015]  Possible unsafe locking scenario:
> [   37.654015]
> [   37.654015]        CPU0
> [   37.654015]        ----
> [   37.654015]   lock(&ep->mtx);
> [   37.654015]   lock(&ep->mtx);
> [   37.654015]
> [   37.654015]  *** DEADLOCK ***
> [   37.654015]
> [   37.654015]  May be due to missing lock nesting notation
> [   37.654015]
> [   37.654015] 2 locks held by systemd-logind/651:
> [   37.654015]  #0:  (epmutex){+.+.+.}, at: [<c0528a4b>] sys_epoll_ctl+0xbe/0x481
> [   37.654015]  #1:  (&ep->mtx){+.+.+.}, at: [<c0528a90>] sys_epoll_ctl+0x103/0x481
> [   37.654015]
> [   37.654015] stack backtrace:
> [   37.654015] Pid: 651, comm: systemd-logind Not tainted 3.0-0.rc7.git0.1.fc16.i686 #1
> [   37.654015] Call Trace:
> [   37.654015]  [<c08490fe>] ? printk+0x2d/0x2f
> [   37.654015]  [<c046b2ef>] __lock_acquire+0x811/0xb63
> [   37.654015]  [<c0407c77>] ? sched_clock+0x8/0xb
> [   37.654015]  [<c045d190>] ? sched_clock_local+0x10/0x18b
> [   37.654015]  [<c05285f1>] ? ep_scan_ready_list+0x32/0x154
> [   37.654015]  [<c046ba5e>] lock_acquire+0xad/0xe4
> [   37.654015]  [<c05285f1>] ? ep_scan_ready_list+0x32/0x154
> [   37.654015]  [<c08506bd>] __mutex_lock_common+0x49/0x2ee
> [   37.654015]  [<c05285f1>] ? ep_scan_ready_list+0x32/0x154
> [   37.654015]  [<c04332e6>] ? __might_sleep+0x29/0xfb
> [   37.654015]  [<c046a912>] ? mark_lock+0x26/0x1f2
> [   37.654015]  [<c0850a7c>] mutex_lock_nested+0x43/0x49
> [   37.654015]  [<c05285f1>] ? ep_scan_ready_list+0x32/0x154
> [   37.654015]  [<c05285f1>] ep_scan_ready_list+0x32/0x154
> [   37.654015]  [<c05281cb>] ? ep_remove+0x9b/0x9b
> [   37.654015]  [<c0528727>] ep_poll_readyevents_proc+0x14/0x16
> [   37.654015]  [<c05283d6>] ep_call_nested.constprop.2+0x6d/0x9a
> [   37.654015]  [<c0528713>] ? ep_scan_ready_list+0x154/0x154
> [   37.654015]  [<c05284d2>] ep_eventpoll_poll+0x45/0x55
> [   37.654015]  [<c0528b8c>] sys_epoll_ctl+0x1ff/0x481
> [   37.654015]  [<c05282fb>] ? ep_send_events_proc+0xd5/0xd5
> [   37.654015]  [<c08521ac>] syscall_call+0x7/0xb


Lennart

-- 
Lennart Poettering - Red Hat, Inc.