Re: 2.6.24-rc7 to 2.6.24-rc8 possible regression

From: Stefan Richter
Date: Mon Jan 21 2008 - 17:46:12 EST


Denys Fedoryshchenko wrote:
> After running screen found in dmesg. It was not happening before.
>
> [625138.248257]
> [625138.248260] =============================================
> [625138.248542] [ INFO: possible recursive locking detected ]
> [625138.248686] 2.6.24-rc8-devel #2
> [625138.248821] ---------------------------------------------
> [625138.248963] screen/18164 is trying to acquire lock:
> [625138.249101] (&q->lock){++..}, at: [<c01175ff>] __wake_up+0x15/0x42
> [625138.249454]
> [625138.249456] but task is already holding lock:
> [625138.249724] (&q->lock){++..}, at: [<c01175ff>] __wake_up+0x15/0x42
> [625138.250073]
> [625138.250075] other info that might help us debug this:
> [625138.250343] 2 locks held by screen/18164:
> [625138.250477] #0: (&tty->atomic_read_lock){--..}, at: [<c0231a6c>]
> read_chan+0x18f/0x50b
> [625138.250960] #1: (&q->lock){++..}, at: [<c01175ff>] __wake_up+0x15/0x42
> [625138.251356]
> [625138.251357] stack backtrace:
> [625138.251623] Pid: 18164, comm: screen Not tainted 2.6.24-rc8-devel #2
> [625138.251764] [<c0105e84>] show_trace_log_lvl+0x1a/0x2f
> [625138.251959] [<c010682c>] show_trace+0x12/0x14
> [625138.252150] [<c0107123>] dump_stack+0x6c/0x72
> [625138.252338] [<c01384c0>] __lock_acquire+0x172/0xb8c
> [625138.252533] [<c01392a7>] lock_acquire+0x5f/0x78
> [625138.252725] [<c032afa7>] _spin_lock_irqsave+0x34/0x44
> [625138.252920] [<c01175ff>] __wake_up+0x15/0x42
> [625138.253108] [<c0186a16>] ep_poll_safewake+0x8e/0xbf
> [625138.253300] [<c01876df>] ep_poll_callback+0x9f/0xac
> [625138.253491] [<c0115d36>] __wake_up_common+0x32/0x5c
> [625138.253688] [<c011761b>] __wake_up+0x31/0x42
> [625138.253878] [<c022c803>] tty_wakeup+0x4f/0x54
> [625138.254070] [<c0232c7c>] pty_unthrottle+0x15/0x21
> [625138.254258] [<c022ffe3>] check_unthrottle+0x2e/0x30
> [625138.254445] [<c0231cf4>] read_chan+0x417/0x50b
> [625138.254633] [<c022ec67>] tty_read+0x66/0xac
> [625138.254819] [<c01628dc>] vfs_read+0x8e/0x117
> [625138.255004] [<c0162d10>] sys_read+0x3d/0x61
> [625138.255190] [<c0104dee>] sysenter_past_esp+0x5f/0xa5
> [625138.255376] =======================

Do you have Peter's lockdep annotation patch for epoll applied?
http://lkml.org/lkml/2008/1/13/84
--
Stefan Richter
-=====-==--- ---= =-=-=
http://arcgraph.de/sr/
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