[Xen-changelog] [xen master] x86/ioapic: avoid trying to access the -1th ioapic

[patchbot@xxxxxxx]

commit ef0ea8c2bbb3718df1dee8f15ff3206bf592b253
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Tue Sep 10 16:40:34 2013 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Sep 10 16:40:34 2013 +0200

    x86/ioapic: avoid trying to access the -1th ioapic
    
    Discovered by Coverity, CID 1055743
    
    Depending on the contents of the mp_irqs/mp_ioapics from the MP table,
    find_isa_irq_apic() might return -1, at which point calling
    ioapic_read_entry() with it is bad.
    
    In addition to bailing if pin is -1, bail if apic is -1.
    
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Acked-by: Keir Fraser <keir@xxxxxxx>
---
 xen/arch/x86/io_apic.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/xen/arch/x86/io_apic.c b/xen/arch/x86/io_apic.c
index 048c61c..5512cd5 100644
--- a/xen/arch/x86/io_apic.c
+++ b/xen/arch/x86/io_apic.c
@@ -1828,7 +1828,7 @@ static void __init unlock_ExtINT_logic(void)
 
     pin = find_isa_irq_pin(8, mp_INT);
     apic = find_isa_irq_apic(8, mp_INT);
-    if (pin == -1)
+    if ( pin == -1 || apic == -1 )
         return;
 
     entry0 = ioapic_read_entry(apic, pin, 0);
--
generated by git-patchbot for /home/xen/git/xen.git#master

_______________________________________________
Xen-changelog mailing list
Xen-changelog@xxxxxxxxxxxxx
http://lists.xensource.com/xen-changelog