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 4.9-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-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From a77660d231f8b3d84fd23ed482e0964f7aa546d6 Mon Sep 17 00:00:00 2001
From: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Date: Tue, 6 Feb 2018 15:40:28 -0800
Subject: kcov: detect double association with a single task
From: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
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.
Link: http://lkml.kernel.org/r/20180122082520.15716-1-dvyukov@xxxxxxxxxx
Fixes: 5c9a8750a640 ("kernel: add kcov code coverage")
Signed-off-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Reported-by: Shankara Pailoor <sp3485@xxxxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: syzbot <syzkaller@xxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/kcov.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/kernel/kcov.c
+++ b/kernel/kcov.c
@@ -220,9 +220,9 @@ 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 dvyukov@xxxxxxxxxx are
queue-4.9/kvm-x86-fix-escape-of-guest-dr6-to-the-host.patch
queue-4.9/blktrace-fix-unlocked-registration-of-tracepoints.patch
queue-4.9/netfilter-x_tables-fix-int-overflow-in-xt_alloc_table_info.patch
queue-4.9/netfilter-ipt_clusterip-fix-out-of-bounds-accesses-in-clusterip_tg_check.patch
queue-4.9/kcov-detect-double-association-with-a-single-task.patch