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bpfilter: Take advantage of the facilities of struct pid

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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>
This commit is contained in:
Eric W. Biederman
2020-06-25 17:23:22 -05:00
parent 38fd525a4c
commit e80eb1dc86
3 changed files with 15 additions and 18 deletions
Download Patch File Download Diff File Expand all files Collapse all files

15
net/bpfilter/bpfilter_kern.c
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@@ -18,10 +18,11 @@ static void shutdown_umh(void)
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)
@@ -77,7 +78,6 @@ static int start_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 */
@@ -100,16 +100,11 @@ static int __init load_umh(void)
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);