ARM: Ensure correct might_sleep() check in pagefault path

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

1 files changed, 7 insertions, 0 deletions

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);