Instead of relying on the exit_umh cleanup callback use the fact a
struct pid can be tested to see if a process still exists, and that
struct pid has a wait queue that notifies when the process dies.
v1: https://lkml.kernel.org/r/87h7uydlu9.fsf_-_@x220.int.ebiederm.org
v2: https://lkml.kernel.org/r/874kqt4owu.fsf_-_@x220.int.ebiederm.org
Link: https://lkml.kernel.org/r/20200702164140.4468-14-ebiederm@xmission.com
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
unsigned int optlen);
int bpfilter_ip_get_sockopt(struct sock *sk, int optname, char __user *optval,
int __user *optlen);
+void bpfilter_umh_cleanup(struct umd_info *info);
+
struct bpfilter_umh_ops {
struct umd_info info;
/* since ip_getsockopt() can run in parallel, serialize access to umh */
char __user *optval,
unsigned int optlen, bool is_set);
int (*start)(void);
- bool stop;
};
extern struct bpfilter_umh_ops bpfilter_ops;
#endif
struct umd_info *info = &bpfilter_ops.info;
struct pid *tgid = info->tgid;
- if (bpfilter_ops.stop)
- return;
-
- kill_pid(tgid, SIGKILL, 1);
+ if (tgid) {
+ kill_pid(tgid, SIGKILL, 1);
+ wait_event(tgid->wait_pidfd, thread_group_exited(tgid));
+ bpfilter_umh_cleanup(info);
+ }
}
static void __stop_umh(void)
err = fork_usermode_driver(&bpfilter_ops.info);
if (err)
return err;
- bpfilter_ops.stop = false;
pr_info("Loaded bpfilter_umh pid %d\n", pid_nr(bpfilter_ops.info.tgid));
/* health check that usermode process started correctly */
return err;
mutex_lock(&bpfilter_ops.lock);
- if (!bpfilter_ops.stop) {
- err = -EFAULT;
- goto out;
- }
err = start_umh();
if (!err && IS_ENABLED(CONFIG_INET)) {
bpfilter_ops.sockopt = &__bpfilter_process_sockopt;
bpfilter_ops.start = &start_umh;
}
-out:
mutex_unlock(&bpfilter_ops.lock);
if (err)
umd_unload_blob(&bpfilter_ops.info);
struct bpfilter_umh_ops bpfilter_ops;
EXPORT_SYMBOL_GPL(bpfilter_ops);
-static void bpfilter_umh_cleanup(struct umd_info *info)
+void bpfilter_umh_cleanup(struct umd_info *info)
{
- mutex_lock(&bpfilter_ops.lock);
- bpfilter_ops.stop = true;
fput(info->pipe_to_umh);
fput(info->pipe_from_umh);
put_pid(info->tgid);
info->tgid = NULL;
- mutex_unlock(&bpfilter_ops.lock);
}
+EXPORT_SYMBOL_GPL(bpfilter_umh_cleanup);
static int bpfilter_mbox_request(struct sock *sk, int optname,
char __user *optval,
goto out;
}
}
- if (bpfilter_ops.stop) {
+ if (bpfilter_ops.info.tgid &&
+ thread_group_exited(bpfilter_ops.info.tgid))
+ bpfilter_umh_cleanup(&bpfilter_ops.info);
+
+ if (!bpfilter_ops.info.tgid) {
err = bpfilter_ops.start();
if (err)
goto out;
static int __init bpfilter_sockopt_init(void)
{
mutex_init(&bpfilter_ops.lock);
- bpfilter_ops.stop = true;
+ bpfilter_ops.info.tgid = NULL;
bpfilter_ops.info.driver_name = "bpfilter_umh";
- bpfilter_ops.info.cleanup = &bpfilter_umh_cleanup;
return 0;
}