Messages in this thread | | | From | Rodrigo Campos <> | Date | Fri, 29 Apr 2022 11:42:15 +0200 | Subject | Re: [PATCH v3 1/2] seccomp: Add wait_killable semantic to seccomp user notifier |
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On Fri, Apr 29, 2022 at 4:32 AM Sargun Dhillon <sargun@sargun.me> wrote: > the concept is searchable. If the notifying process is signaled prior > to the notification being received by the userspace agent, it will > be handled as normal.
Why is that? Why not always handle in the same way (if wait killable is set, wait like that)
> diff --git a/kernel/seccomp.c b/kernel/seccomp.c > index db10e73d06e0..9291b0843cb2 100644 > --- a/kernel/seccomp.c > +++ b/kernel/seccomp.c > @@ -1081,6 +1088,12 @@ static void seccomp_handle_addfd(struct seccomp_kaddfd *addfd, struct seccomp_kn > complete(&addfd->completion); > } > > +static bool should_sleep_killable(struct seccomp_filter *match, > + struct seccomp_knotif *n) > +{ > + return match->wait_killable_recv && n->state == SECCOMP_NOTIFY_SENT;
Here for some reason we check the notification state to be SENT.
> +} > + > static int seccomp_do_user_notification(int this_syscall, > struct seccomp_filter *match, > const struct seccomp_data *sd) > @@ -1111,11 +1124,25 @@ static int seccomp_do_user_notification(int this_syscall, > * This is where we wait for a reply from userspace. > */ > do { > + bool wait_killable = should_sleep_killable(match, &n); > +
So here, the first time this runs this will be false even if the wait_killable flag was used in the filter (because that function checks the notification state to be sent, that is not true the first time)
Why not just do wait_for_completion_killable if match->wait_killable and wait_for_completion_interruptible otherwise? Am I missing something?
Best, Rodrigo
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