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authorAndi Kleen <andi@firstfloor.org>2009-12-08 13:19:42 +0100
committerThomas Gleixner <tglx@linutronix.de>2009-12-08 15:03:26 +0100
commitcc24da0742870f152ddf1002aa39dfcd83f7cf9c (patch)
tree2cf6a4209372892aa24ff30cf7a41ab5574ac62e
parent05d5f5080a2e3fbbc0f762875b66721588f5e251 (diff)
futex: Take mmap_sem for get_user_pages in fault_in_user_writeablev2.6.31-rt-head
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>
-rw-r--r--kernel/futex.c10
1 files changed, 8 insertions, 2 deletions
diff --git a/kernel/futex.c b/kernel/futex.c
index b2400110b6c8..da333ceed739 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -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,
- 1, 1, 0, NULL, NULL);
+ 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;
}