Commit 722d0172 authored Dec 08, 2009 by Andi Kleen Committed by Thomas Gleixner Dec 08, 2009

futex: Take mmap_sem for get_user_pages in fault_in_user_writeable



get_user_pages() must be called with mmap_sem held.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: stable@kernel.org
Cc: Andrew Morton <akpm@linuxfoundation.org>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Darren Hart <dvhltc@us.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <20091208121942.GA21298@basil.fritz.box>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

parent f5754bfd

kernel/futex.c

+8 −2

Original line number	Diff line number	Diff line
		@@ -304,8 +304,14 @@ void put_futex_key(int fshared, union futex_key *key)
		*/
		static int fault_in_user_writeable(u32 __user *uaddr)
		{
		int ret = get_user_pages(current, current->mm, (unsigned long)uaddr,
		struct mm_struct *mm = current->mm;
		int ret;

		down_read(&mm->mmap_sem);
		ret = get_user_pages(current, mm, (unsigned long)uaddr,
		1, 1, 0, NULL, NULL);
		up_read(&mm->mmap_sem);

		return ret < 0 ? ret : 0;
		}