Messages in this thread | | | Date | Thu, 9 Jun 2011 00:49:41 +0200 | From | Frederic Weisbecker <> | Subject | Bug: ACPI, scheduling while atomic (was Re: [PATCH 0/4] sched: Make sleep inside atomic detection work on !PREEMPT) |
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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.
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