Patch "kcov: detect double association with a single task" has been added to the 4.14-stable tree

This is a note to let you know that I've just added the patch titled

kcov: detect double association with a single task

to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
kcov-detect-double-association-with-a-single-task.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Dmitry Vyukov <[email protected]>
Date: Tue, 6 Feb 2018 15:40:28 -0800
Subject: kcov: detect double association with a single task

From: Dmitry Vyukov <[email protected]>

commit a77660d231f8b3d84fd23ed482e0964f7aa546d6 upstream.

Currently KCOV_ENABLE does not check if the current task is already associated with another kcov descriptor. As the result it is possible to associate a single task with more than one kcov descriptor, which later leads to a memory leak of the old descriptor. This relation is really meant to be one-to-one (task has only one back link).

Extend validation to detect such misuse.

---
 kernel/kcov.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

@@ -225,9 +225,9 @@ static int kcov_ioctl_locked(struct kcov
 		if (unused != 0 || kcov->mode == KCOV_MODE_DISABLED ||
 		    kcov->area == NULL)
 			return -EINVAL;
-		if (kcov->t != NULL)
-			return -EBUSY;
 		t = current;
+		if (kcov->t != NULL || t->kcov != NULL)
+			return -EBUSY;
 		/* Cache in task struct for performance. */
 		t->kcov_size = kcov->size;
 		t->kcov_area = kcov->area;

Patches currently in stable-queue which might be from [email protected] are

queue-4.14/kvm-x86-check-input-paging-mode-when-cs.l-is-set.patch queue-4.14/kvm-x86-fix-escape-of-guest-dr6-to-the-host.patch queue-4.14/blktrace-fix-unlocked-registration-of-tracepoints.patch queue-4.14/netfilter-x_tables-fix-int-overflow-in-xt_alloc_table_info.patch queue-4.14/netfilter-ipt_clusterip-fix-out-of-bounds-accesses-in-clusterip_tg_check.patch queue-4.14/kcov-detect-double-association-with-a-single-task.patch