[GIT pull] x86 fixes for 4.3

[Thomas Gleixner]

Linus,

please pull the latest x86-urgent-for-linus git tree from:

   git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git 
x86-urgent-for-linus

This set of updates contains:

     - Another bugfix for the pathologic vm86 machinery. Clear
       thread.vm86 on fork to prevent corrupting the parent
       state. This comes along with an update to the vm86 selftest
       case

     - Fix another corner case in the ioapic setup code which causes
       a boot crash on some oddball systems

     - Fix the fallout from the dma allocation consolidation work,
       which leads to a NULL pointer dereference when the allocation
       code is called with a NULL device.

Thanks,

        tglx

------------------>
Andy Lutomirski (2):
      selftests/x86: Add a fork() to entry_from_vm86 to catch fork bugs
      x86/vm86: Set thread.vm86 to NULL on fork/clone

Ville Syrjälä (1):
      x86/dma-mapping: Fix arch_dma_alloc_attrs() oops with NULL dev

Werner Pawlitschko (1):
      x86/ioapic: Prevent NULL pointer dereference in setup_ioapic_dest()


 arch/x86/kernel/apic/io_apic.c                | 4 +++-
 arch/x86/kernel/pci-dma.c                     | 5 +++--
 arch/x86/kernel/process.c                     | 3 +++
 tools/testing/selftests/x86/entry_from_vm86.c | 4 ++++
 4 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index bb6bfc01cb82..4f2821527014 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -2547,7 +2547,9 @@ void __init setup_ioapic_dest(void)
                        mask = apic->target_cpus();
 
                chip = irq_data_get_irq_chip(idata);
-               chip->irq_set_affinity(idata, mask, false);
+               /* Might be lapic_chip for irq 0 */
+               if (chip->irq_set_affinity)
+                       chip->irq_set_affinity(idata, mask, false);
        }
 }
 #endif
diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index 1b55de1267cf..cd99433b8ba1 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -131,11 +131,12 @@ void dma_generic_free_coherent(struct device *dev, size_t 
size, void *vaddr,
 
 bool arch_dma_alloc_attrs(struct device **dev, gfp_t *gfp)
 {
+       if (!*dev)
+               *dev = &x86_dma_fallback_dev;
+
        *gfp &= ~(__GFP_DMA | __GFP_HIGHMEM | __GFP_DMA32);
        *gfp = dma_alloc_coherent_gfp_flags(*dev, *gfp);
 
-       if (!*dev)
-               *dev = &x86_dma_fallback_dev;
        if (!is_device_dma_capable(*dev))
                return false;
        return true;
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index e28db181e4fc..9f7c21c22477 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -84,6 +84,9 @@ EXPORT_SYMBOL_GPL(idle_notifier_unregister);
 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
 {
        memcpy(dst, src, arch_task_struct_size);
+#ifdef CONFIG_VM86
+       dst->thread.vm86 = NULL;
+#endif
 
        return fpu__copy(&dst->thread.fpu, &src->thread.fpu);
 }
diff --git a/tools/testing/selftests/x86/entry_from_vm86.c 
b/tools/testing/selftests/x86/entry_from_vm86.c
index 421c607a8856..d075ea0e5ca1 100644
--- a/tools/testing/selftests/x86/entry_from_vm86.c
+++ b/tools/testing/selftests/x86/entry_from_vm86.c
@@ -230,5 +230,9 @@ int main(void)
        }
        clearhandler(SIGSEGV);
 
+       /* Make sure nothing explodes if we fork. */
+       if (fork() > 0)
+               return 0;
+
        return (nerrs == 0 ? 0 : 1);
 }