Messages in this thread | | | Subject | Re: [PATCH v2 00/15] Make the user mode driver code a better citizen | From | Tetsuo Handa <> | Date | Tue, 30 Jun 2020 22:21:19 +0900 |
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On 2020/06/30 21:29, Eric W. Biederman wrote: > Hmm. The wake up happens just of tgid->wait_pidfd happens just before > release_task is called so there is a race. As it is possible to wake > up and then go back to sleep before pid_has_task becomes false.
What is the reason we want to wait until pid_has_task() becomes false?
- wait_event(tgid->wait_pidfd, !pid_has_task(tgid, PIDTYPE_TGID)); + while (!wait_event_timeout(tgid->wait_pidfd, !pid_has_task(tgid, PIDTYPE_TGID), 1));
By the way, commit 4a9d4b024a3102fc ("switch fput to task_work_add") says that use of flush_delayed_fput() has to be careful. Al, is it safe to call flush_delayed_fput() from blob_to_mnt() from umd_load_blob() (which might be called from both kernel thread and from process context (e.g. init_module() syscall by /sbin/insmod )) ?
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