diff options
| author | Shaohua Li <shli@fb.com> | 2017-11-07 11:09:50 -0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2017-11-10 19:53:25 -0700 |
| commit | e10237cc76ef9a4066a84aa2cc710bfd708cc341 (patch) | |
| tree | 6e096297e263119d7c6b80f7e8ff538827e04e3f /kernel/kthread.c | |
| parent | 18c53e40487f56369c3ba9331ec3597d9b48d97c (diff) | |
| download | lwn-e10237cc76ef9a4066a84aa2cc710bfd708cc341.tar.gz lwn-e10237cc76ef9a4066a84aa2cc710bfd708cc341.zip | |
kthread: zero the kthread data structure
kthread() could bail out early before we initialize blkcg_css (if the
kthread is killed very early. Please see xchg() statement in kthread()),
which confuses free_kthread_struct. Instead of moving the blkcg_css
initialization early, we simply zero the whole 'self' data structure,
which doesn't sound much overhead.
Reported-by: syzbot <syzkaller@googlegroups.com>
Fixes: 05e3db95ebfc ("kthread: add a mechanism to store cgroup info")
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'kernel/kthread.c')
| -rw-r--r-- | kernel/kthread.c | 6 |
1 files changed, 1 insertions, 5 deletions
diff --git a/kernel/kthread.c b/kernel/kthread.c index f87cd8b4eb2a..8dbe2454cb1d 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -204,7 +204,7 @@ static int kthread(void *_create) struct kthread *self; int ret; - self = kmalloc(sizeof(*self), GFP_KERNEL); + self = kzalloc(sizeof(*self), GFP_KERNEL); set_kthread_struct(self); /* If user was SIGKILLed, I release the structure. */ @@ -220,13 +220,9 @@ static int kthread(void *_create) do_exit(-ENOMEM); } - self->flags = 0; self->data = data; init_completion(&self->exited); init_completion(&self->parked); -#ifdef CONFIG_BLK_CGROUP - self->blkcg_css = NULL; -#endif current->vfork_done = &self->exited; /* OK, tell user we're spawned, wait for stop or wakeup */ |