Latest working kernel version: 2.6.24-rc7 Earliest failing kernel version: 2.6.24-rc8 Distribution: Gentoo Hardware Environment: Dell Software Environment: Problem Description: Steps to reproduce: I didnt catch how to reproduce, appeared while worked in screen Here is dmesg [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] =======================
References : http://lkml.org/lkml/2008/1/21/179
Earlier report and discussion of the cause: http://lkml.org/lkml/2008/1/3/350 Lockdep annotation patch: http://lkml.org/lkml/2008/1/13/84
Lockdep annotation patch reposted: http://lkml.org/lkml/2008/1/22/345
patch added to -mm http://marc.info/?l=linux-mm-commits&m=120104316528878
I test patch and it seems fixing issue, for now tested only during 1 day, but seems not causing any issues. Probably it must find way to mainline asap, otherwise this cosmetic(?) bug will cause a lot of fake bug reports like mine.