From: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
To: rpm@xenomai.org
Cc: Jan Kiszka <jan.kiszka@domain.hid>, xenomai-core <xenomai@xenomai.org>
Subject: Re: [Xenomai-core] [BUG] trunk: screwed Linux irq state
Date: Mon, 12 Feb 2007 00:07:09 +0100 [thread overview]
Message-ID: <17871.41373.425284.839228@domain.hid> (raw)
In-Reply-To: <1171233732.5035.24.camel@domain.hid>
Philippe Gerum wrote:
> On Sun, 2007-02-11 at 23:13 +0100, Jan Kiszka wrote:
> > Hi,
> >
> > while testing 2.6.20 with RTnet, I got this kernel BUG during the slave
> > startup procedure:
> >
> > <4>[ 137.799234] TDMA: calibrated master-to-slave packet delay: 34 us (min/max: 33/38 us)
> > <4>[ 142.291455] BUG: at kernel/fork.c:993 copy_process()
> > <4>[ 142.291585] [<c0103a8f>] show_trace_log_lvl+0x1f/0x40
> > <4>[ 142.291767] [<c0104237>] show_trace+0x17/0x20
> > <4>[ 142.291896] [<c010432b>] dump_stack+0x1b/0x20
> > <4>[ 142.292026] [<c0111e94>] copy_process+0x914/0x13d0
> > <4>[ 142.292190] [<c0112b80>] do_fork+0x70/0x1b0
> > <4>[ 142.292323] [<c0101078>] sys_clone+0x38/0x40
> > <4>[ 142.292620] [<c010320f>] syscall_call+0x7/0xb
> > <4>[ 142.292747] =======================
> > <3>[ 142.292860] BUG: sleeping function called from invalid context at mm/slab.c:3034
> > <4>[ 142.293052] in_atomic():0, irqs_disabled():1
> ^^^^
>
> Typical of something going wrong in entry.S.
You mean, interrupts are not really disabled when forking ? :-)
So, I am afraid the new fpu_counter optimization is buggy: if a task
forks with fpu_counter greater than 5 and is preempted right after
prepare_to_copy in dup_task_struct, when the system switches back to
this task, the task FPU context will be restored and TS_USEDFPU set in
the task flags, thereby voiding the effect of prepare_to_copy.
--
Gilles Chanteperdrix.
next prev parent reply other threads:[~2007-02-11 23:07 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-02-11 22:13 [Xenomai-core] [BUG] trunk: screwed Linux irq state Jan Kiszka
2007-02-11 22:26 ` Gilles Chanteperdrix
2007-02-11 22:31 ` Gilles Chanteperdrix
2007-02-11 22:42 ` Philippe Gerum
2007-02-11 23:07 ` Gilles Chanteperdrix [this message]
2007-02-11 23:49 ` Philippe Gerum
2007-02-12 0:20 ` Gilles Chanteperdrix
2007-02-12 0:28 ` Jan Kiszka
2007-02-12 1:10 ` Jan Kiszka
2007-02-12 11:49 ` Jan Kiszka
2007-02-12 13:16 ` Gilles Chanteperdrix
2007-02-12 13:46 ` Philippe Gerum
2007-02-12 13:49 ` Jan Kiszka
2007-02-12 14:10 ` Philippe Gerum
2007-02-12 14:39 ` Gilles Chanteperdrix
2007-02-12 15:10 ` Philippe Gerum
2007-02-12 19:02 ` Gilles Chanteperdrix
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