The patch titled
Subject: kcov: detect double association with a single task
has been added to the -mm tree. Its filename is
kcov-detect-double-association-with-a-single-task.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/kcov-detect-double-association-with-a-single-task.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/kcov-detect-double-association-with-a-single-task.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Subject: kcov: detect double association with a single task
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>
---
kernel/kcov.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff -puN kernel/kcov.c~kcov-detect-double-association-with-a-single-task kernel/kcov.c
--- a/kernel/kcov.c~kcov-detect-double-association-with-a-single-task
+++ a/kernel/kcov.c
@@ -358,7 +358,8 @@ static int kcov_ioctl_locked(struct kcov
*/
if (kcov->mode != KCOV_MODE_INIT || !kcov->area)
return -EINVAL;
- if (kcov->t != NULL)
+ t = current;
+ if (kcov->t != NULL || t->kcov != NULL)
return -EBUSY;
if (arg == KCOV_TRACE_PC)
kcov->mode = KCOV_MODE_TRACE_PC;
@@ -370,7 +371,6 @@ static int kcov_ioctl_locked(struct kcov
#endif
else
return -EINVAL;
- t = current;
/* Cache in task struct for performance. */
t->kcov_size = kcov->size;
t->kcov_area = kcov->area;
_
Patches currently in -mm which might be from dvyukov@xxxxxxxxxx are
kasan-detect-invalid-frees-for-large-objects.patch
kasan-dont-use-__builtin_return_address1.patch
kasan-detect-invalid-frees-for-large-mempool-objects.patch
kasan-unify-code-between-kasan_slab_free-and-kasan_poison_kfree.patch
kasan-detect-invalid-frees.patch
kcov-detect-double-association-with-a-single-task.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
