From: Anton Blanchard <anton@samba.org>
Date: Wed, 14 Jul 2010 19:31:48 +0000 (+0000)
Subject: powerpc/mm: Handle hypervisor pte insert failure in __hash_page_huge
X-Git-Tag: v2.6.35~42^2~6
X-Git-Url: https://bbs.cooldavid.org/git/?a=commitdiff_plain;h=b1623e7eb280f853f60338c7bb68bd3f3a970205;p=net-next-2.6.git

powerpc/mm: Handle hypervisor pte insert failure in __hash_page_huge

If the hypervisor gives us an error on a hugepage insert we panic. The
normal page code already handles this by returning an error instead and we end
calling low_hash_fault which will just kill the task if possible.

The patch below does a similar thing for the hugepage case.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---

diff --git a/arch/powerpc/mm/hugetlbpage-hash64.c b/arch/powerpc/mm/hugetlbpage-hash64.c
index 199539882f9..c9acd7910ee 100644
--- a/arch/powerpc/mm/hugetlbpage-hash64.c
+++ b/arch/powerpc/mm/hugetlbpage-hash64.c
@@ -121,8 +121,15 @@ repeat:
                         }
 		}
 
-		if (unlikely(slot == -2))
-			panic("hash_huge_page: pte_insert failed\n");
+		/*
+		 * Hypervisor failure. Restore old pte and return -1
+		 * similar to __hash_page_*
+		 */
+		if (unlikely(slot == -2)) {
+			*ptep = __pte(old_pte);
+			err = -1;
+			goto out;
+		}
 
 		new_pte |= (slot << 12) & (_PAGE_F_SECOND | _PAGE_F_GIX);
 	}