From: Russell King <rmk+kernel@arm.linux.org.uk>
Date: Sun, 20 Sep 2009 11:52:19 +0000 (+0100)
Subject: ARM: Ensure correct might_sleep() check in pagefault path
X-Git-Url: http://git.efficios.com/?a=commitdiff_plain;h=bf4569922b97824f33e5d08d0bbe4b34fe43e4cd;p=deliverable%2Flinux.git

ARM: Ensure correct might_sleep() check in pagefault path

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
---

diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c
index 501304f7e30c..b8b3bb4423cf 100644
--- a/arch/arm/mm/fault.c
+++ b/arch/arm/mm/fault.c
@@ -271,6 +271,13 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
 		if (!user_mode(regs) && !search_exception_tables(regs->ARM_pc))
 			goto no_context;
 		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();
 	}
 
 	fault = __do_page_fault(mm, addr, fsr, tsk);