From 75df679c581581978487f6f6de91bf86a9f72e7c Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Wed, 14 Dec 2011 01:03:49 +0100
Subject: [PATCH 037/283] cpumask: Disable CONFIG_CPUMASK_OFFSTACK for RT

There are "valid" GFP_ATOMIC allocations such as

|BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:931
|in_atomic(): 1, irqs_disabled(): 0, pid: 2130, name: tar
|1 lock held by tar/2130:
| #0:  (&mm->mmap_sem){++++++}, at: [<ffffffff811d4e89>] SyS_brk+0x39/0x190
|Preemption disabled at:[<ffffffff81063048>] flush_tlb_mm_range+0x28/0x350
|
|CPU: 1 PID: 2130 Comm: tar Tainted: G        W       4.8.2-rt2+ #747
|Call Trace:
| [<ffffffff814d52dc>] dump_stack+0x86/0xca
| [<ffffffff810a26fb>] ___might_sleep+0x14b/0x240
| [<ffffffff819bc1d4>] rt_spin_lock+0x24/0x60
| [<ffffffff81194fba>] get_page_from_freelist+0x83a/0x11b0
| [<ffffffff81195e8b>] __alloc_pages_nodemask+0x15b/0x1190
| [<ffffffff811f0b81>] alloc_pages_current+0xa1/0x1f0
| [<ffffffff811f7df5>] new_slab+0x3e5/0x690
| [<ffffffff811fb0d5>] ___slab_alloc+0x495/0x660
| [<ffffffff811fb311>] __slab_alloc.isra.79+0x71/0xc0
| [<ffffffff811fb447>] __kmalloc_node+0xe7/0x240
| [<ffffffff814d4ee0>] alloc_cpumask_var_node+0x20/0x50
| [<ffffffff814d4f3e>] alloc_cpumask_var+0xe/0x10
| [<ffffffff810430c1>] native_send_call_func_ipi+0x21/0x130
| [<ffffffff8111c13f>] smp_call_function_many+0x22f/0x370
| [<ffffffff81062b64>] native_flush_tlb_others+0x1a4/0x3a0
| [<ffffffff8106309b>] flush_tlb_mm_range+0x7b/0x350
| [<ffffffff811c88e2>] tlb_flush_mmu_tlbonly+0x62/0xd0
| [<ffffffff811c9af4>] tlb_finish_mmu+0x14/0x50
| [<ffffffff811d1c84>] unmap_region+0xe4/0x110
| [<ffffffff811d3db3>] do_munmap+0x293/0x470
| [<ffffffff811d4f8c>] SyS_brk+0x13c/0x190
| [<ffffffff810032e2>] do_fast_syscall_32+0xb2/0x2f0
| [<ffffffff819be181>] entry_SYSENTER_compat+0x51/0x60

which forbid allocations at run-time.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 arch/x86/Kconfig | 2 +-
 lib/Kconfig      | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index e76d16ac2776..04a45d6d0167 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -934,7 +934,7 @@ config CALGARY_IOMMU_ENABLED_BY_DEFAULT
 config MAXSMP
 	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
 	depends on X86_64 && SMP && DEBUG_KERNEL
-	select CPUMASK_OFFSTACK
+	select CPUMASK_OFFSTACK if !PREEMPT_RT_FULL
 	---help---
 	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
 	  If unsure, say N.
diff --git a/lib/Kconfig b/lib/Kconfig
index a3928d4438b5..a50b2158f7cd 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -441,6 +441,7 @@ config CHECK_SIGNATURE
 
 config CPUMASK_OFFSTACK
 	bool "Force CPU masks off stack" if DEBUG_PER_CPU_MAPS
+	depends on !PREEMPT_RT_FULL
 	help
 	  Use dynamic allocation for cpumask_var_t, instead of putting
 	  them on the stack.  This is a bit more expensive, but avoids
-- 
2.20.1

