* Luis Claudio R. Goncalves | 2013-09-11 07:28:09 [-0300]:
>Hello,
Hi Luis,
>after Xorg started. I silenced that with a hackish patch, just for fun, and
>found a second problem, this time on tty_ldisc_reinit().
>
>[ 25.423675] BUG: sleeping function called from invalid context at /home/lclaudio/SANDBOX/mrg-rt-v2-devel/kernel/rtmutex.c:659
>[ 25.423676] in_atomic(): 1, irqs_disabled(): 1, pid: 188, name: plymouthd
>[ 25.423676] 3 locks held by plymouthd/188:
>[ 25.423682] #0: (&tty->legacy_mutex){......}, at: [<ffffffff816528d0>] tty_lock_nested+0x40/0x90
>[ 25.423686] #1: (&tty->ldisc_mutex){......}, at: [<ffffffff8139b482>] tty_ldisc_hangup+0x152/0x300
>[ 25.423688] #2: (tty_ldisc_lock){......}, at: [<ffffffff8139a9c2>] tty_ldisc_reinit+0x72/0x130
>[ 25.423689] Preemption disabled at:[<ffffffff8139a9c2>] tty_ldisc_reinit+0x72/0x130
>[ 25.423691] CPU: 2 PID: 188 Comm: plymouthd Not tainted 3.10.10-rt7+ #6
>[ 25.423692] Hardware name: Hewlett-Packard p7-1512/2ADA, BIOS 8.15 02/05/2013
>[ 25.423694] 005ff00000000000 ffff8801788ada68 ffffffff8164b790 ffff8801788ada80
>[ 25.423695] ffffffff8107e62f ffff8801991ce1a0 ffff8801788adaa0 ffffffff81651ac4
>[ 25.423696] 0000000000000000 ffffea0005e26680 ffff8801788adaf8 ffffffff81130984
>[ 25.423696] Call Trace:
>[ 25.423700] [<ffffffff8164b790>] dump_stack+0x19/0x1b
>[ 25.423702] [<ffffffff8107e62f>] __might_sleep+0xff/0x170
>[ 25.423704] [<ffffffff81651ac4>] rt_spin_lock+0x24/0x60
>[ 25.423707] [<ffffffff81130984>] free_hot_cold_page+0xb4/0x3c0
>[ 25.423710] [<ffffffff81178209>] ?unfreeze_partials.isra.42+0x229/0x2b0
>[ 25.423711] [<ffffffff81130dc7>] __free_pages+0x47/0x70
>[ 25.423713] [<ffffffff81130fb2>] __free_memcg_kmem_pages+0x22/0x50
>[ 25.423714] [<ffffffff81177528>] __free_slab+0xe8/0x1e0
>[ 25.423716] [<ffffffff81177654>] free_delayed+0x34/0x50
>[ 25.423717] [<ffffffff81649633>] __slab_free+0x273/0x36b
>[ 25.423719] [<ffffffff810acde9>] ? get_lock_stats+0x19/0x60
>[ 25.423721] [<ffffffff810ad49e>] ? put_lock_stats.isra.23+0xe/0x40
>[ 25.423722] [<ffffffff81178794>] kfree+0x1c4/0x210
>[ 25.423724] [<ffffffff8139a9f5>] ? tty_ldisc_reinit+0xa5/0x130
>[ 25.423725] [<ffffffff8139a9f5>] tty_ldisc_reinit+0xa5/0x130
>[ 25.423726] [<ffffffff8139b49f>] tty_ldisc_hangup+0x16f/0x300
>[ 25.423728] [<ffffffff81082e1d>] ? get_parent_ip+0xd/0x50
>[ 25.423731] [<ffffffff8104d736>] ? unpin_current_cpu+0x16/0x70
>[ 25.423732] [<ffffffff81392136>] __tty_hangup+0x346/0x460
>[ 25.423733] [<ffffffff81392260>] tty_vhangup+0x10/0x20
>[ 25.423735] [<ffffffff8139d6e1>] pty_close+0x131/0x180
>[ 25.423736] [<ffffffff813936ad>] tty_release+0x11d/0x5f0
>[ 25.423737] [<ffffffff810acde9>] ? get_lock_stats+0x19/0x60
>[ 25.423747] [<ffffffff81009d84>] ? native_sched_clock+0x24/0x80
>[ 25.423749] [<ffffffff81087025>] ? sched_clock_cpu+0xb5/0x100
>[ 25.423750] [<ffffffff810acde9>] ? get_lock_stats+0x19/0x60
>[ 25.423752] [<ffffffff8118eb45>] __fput+0xf5/0x250
>[ 25.423762] [<ffffffff8118ed6e>] ____fput+0xe/0x10
>[ 25.423764] [<ffffffff8106f1cc>] task_work_run+0xac/0xe0
>[ 25.423765] [<ffffffff81002a11>] do_notify_resume+0x91/0xf0
>[ 25.423767] [<ffffffff8165a41c>] int_signal+0x12/0x17
So the thread continues as a i915 bug thread. Now that I looked at it
again I noticed the tty problem which we probably have since v3.8. The
following patch should fix it.
diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c
index 1afe192..bc4ffe4 100644
--- a/drivers/tty/tty_ldisc.c
+++ b/drivers/tty/tty_ldisc.c
@@ -197,9 +197,10 @@ static inline void tty_ldisc_put(struct tty_ldisc *ld)
WARN_ON(!atomic_dec_and_test(&ld->users));
ld->ops->refcount--;
+ raw_spin_unlock_irqrestore(&tty_ldisc_lock, flags);
+
module_put(ld->ops->owner);
kfree(ld);
- raw_spin_unlock_irqrestore(&tty_ldisc_lock, flags);
}
static void *tty_ldiscs_seq_start(struct seq_file *m, loff_t *pos)
--
1.8.4.rc3
Sebastian
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