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Subject: cpumask: Disable CONFIG_CPUMASK_OFFSTACK for RT
From: Thomas Gleixner <tglx@linutronix.de>
Date: Wed, 14 Dec 2011 01:03:49 +0100
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(-)
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -919,7 +919,7 @@ config IOMMU_HELPER
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.
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -417,6 +417,7 @@ 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
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