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authorKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2012-09-04 15:45:17 -0400
committerKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2012-09-05 09:47:41 -0400
commit50e900417b8096939d12a46848f965e27a905e36 (patch)
tree1bd5945867f1071965665381bbe96ef0cd878e37
parentc96aae1f7f393387d160211f60398d58463a7e65 (diff)
downloadlinux-linaro-stable-50e900417b8096939d12a46848f965e27a905e36.tar.gz
xen/p2m: Fix one-off error in checking the P2M tree directory.
We would traverse the full P2M top directory (from 0->MAX_DOMAIN_PAGES inclusive) when trying to figure out whether we can re-use some of the P2M middle leafs. Which meant that if the kernel was compiled with MAX_DOMAIN_PAGES=512 we would try to use the 512th entry. Fortunately for us the p2m_top_index has a check for this: BUG_ON(pfn >= MAX_P2M_PFN); which we hit and saw this: (XEN) domain_crash_sync called from entry.S (XEN) Domain 0 (vcpu#0) crashed on cpu#0: (XEN) ----[ Xen-4.1.2-OVM x86_64 debug=n Tainted: C ]---- (XEN) CPU: 0 (XEN) RIP: e033:[<ffffffff819cadeb>] (XEN) RFLAGS: 0000000000000212 EM: 1 CONTEXT: pv guest (XEN) rax: ffffffff81db5000 rbx: ffffffff81db4000 rcx: 0000000000000000 (XEN) rdx: 0000000000480211 rsi: 0000000000000000 rdi: ffffffff81db4000 (XEN) rbp: ffffffff81793db8 rsp: ffffffff81793d38 r8: 0000000008000000 (XEN) r9: 4000000000000000 r10: 0000000000000000 r11: ffffffff81db7000 (XEN) r12: 0000000000000ff8 r13: ffffffff81df1ff8 r14: ffffffff81db6000 (XEN) r15: 0000000000000ff8 cr0: 000000008005003b cr4: 00000000000026f0 (XEN) cr3: 0000000661795000 cr2: 0000000000000000 Fixes-Oracle-Bug: 14570662 CC: stable@vger.kernel.org # only for v3.5 Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
-rw-r--r--arch/x86/xen/p2m.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
index d4b255463253..76ba0e97e530 100644
--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -599,7 +599,7 @@ bool __init early_can_reuse_p2m_middle(unsigned long set_pfn, unsigned long set_
if (p2m_index(set_pfn))
return false;
- for (pfn = 0; pfn <= MAX_DOMAIN_PAGES; pfn += P2M_PER_PAGE) {
+ for (pfn = 0; pfn < MAX_DOMAIN_PAGES; pfn += P2M_PER_PAGE) {
topidx = p2m_top_index(pfn);
if (!p2m_top[topidx])