From: Peter Zijlstra <peterz@infradead.org>
Date: Thu, 29 Jan 2009 15:02:12 +0000 (+0100)
Subject: x86: add might_sleep() to do_page_fault()
X-Git-Tag: upstream/snapshot3+hdmi~18661^2~508^2~1^2~2
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=010060741ad35eacb504414bc6fb9bb575b15f62;p=platform%2Fadaptation%2Frenesas_rcar%2Frenesas_kernel.git

x86: add might_sleep() to do_page_fault()

Impact: widen debug checks

VirtualBox calls do_page_fault() from an atomic context but runs into a
might_sleep() way pas this point, cure that.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---

diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 8f4b859..eb4d7fe 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -888,6 +888,12 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code)
 			return;
 		}
 		down_read(&mm->mmap_sem);
+	} else {
+		/*
+		 * The above down_read_trylock() might have succeeded in which
+		 * case we'll have missed the might_sleep() from down_read().
+		 */
+		might_sleep();
 	}
 
 	vma = find_vma(mm, address);