Re: Bug: ACPI, scheduling while atomic (was Re: [PATCH 0/4] sched: Make sleep inside atomic detection work on !PREEMPT)

Frederic Weisbecker
2011-08-27T15:32:57Z

On Wed, Aug 24, 2011 at 08:57:45PM -0700, Randy Dunlap wrote:
> On Thu, 9 Jun 2011 00:49:41 +0200 Frederic Weisbecker wrote:
>
> > On Wed, Jun 08, 2011 at 07:48:31PM +0200, Frederic Weisbecker wrote:
> > > Aside it may mostly avoid the need for a specific PROVE_RCU
> > > check when we sleep inside an rcu read side critical section.
> > >
> > > Better make sleeping inside atomic sections work everywhere.
> >
> > BTW, it has led to detect a bug in the ACPI code. It happens in
> > !CONFIG_PREEMPT:
> >
> > [ 0.160187] BUG: scheduling while atomic: swapper/0/0x10000002
> > [ 0.166016] no locks held by swapper/0.
> > [ 0.170014] Modules linked in:
> > [ 0.173107] Pid: 0, comm: swapper Not tainted 2.6.39+ #124
> > [ 0.180014] Call Trace:
> > [ 0.182481] [<ffffffff81048685>] __schedule_bug+0x85/0x90
> > [ 0.187967] [<ffffffff817da98c>] schedule+0x75c/0xa40
> > [ 0.190022] [<ffffffff8109a1fd>] ? trace_hardirqs_on+0xd/0x10
> > [ 0.200023] [<ffffffff813879c0>] ? acpi_ps_free_op+0x22/0x24
> > [ 0.205776] [<ffffffff810554a5>] __cond_resched+0x25/0x40
> > [ 0.210022] [<ffffffff817daf3b>] _cond_resched+0x2b/0x40
> > [ 0.215420] [<ffffffff81386cbe>] acpi_ps_complete_op+0x262/0x278
> > [ 0.220023] [<ffffffff813874df>] acpi_ps_parse_loop+0x80b/0x960
> > [ 0.230023] [<ffffffff81386607>] acpi_ps_parse_aml+0x98/0x274
> > [ 0.235859] [<ffffffff81384cbb>] acpi_ns_one_complete_parse+0x103/0x120
> > [ 0.240021] [<ffffffff810886da>] ? up+0x2a/0x50
> > [ 0.244641] [<ffffffff81384cf3>] acpi_ns_parse_table+0x1b/0x34
> > [ 0.250022] [<ffffffff8138242a>] acpi_ns_load_table+0x4a/0x8c
> > [ 0.260023] [<ffffffff8138947c>] acpi_load_tables+0x9c/0x15d
> > [ 0.265774] [<ffffffff81d0b0f8>] acpi_early_init+0x6c/0xf7
> > [ 0.270022] [<ffffffff81cd8d31>] start_kernel+0x400/0x415
> > [ 0.275508] [<ffffffff81cd8346>] x86_64_start_reservations+0x131/0x135
> > [ 0.280022] [<ffffffff81cd844d>] x86_64_start_kernel+0x103/0x112
> >
> > ACPI_PREEMPTION_POINT() is called from acpi_ps_complete_op() and schedules
> > if !PREEMPT. But preemption is disabled as we are in early bootup.
>
> This still happens in 3.1-rc[123].
> Was there a patch for it?

I think this patch should fix it, and may make it to mainline soon: