Messages in this thread | | | Date | Tue, 17 Jul 2018 12:18:12 +0200 | From | Oleg Nesterov <> | Subject | Re: [RFC][PATCH 07/11] signal: Deliver group signals via PIDTYPE_TGID not PIDTYPE_PID |
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On 07/17, Oleg Nesterov wrote: > > And, I didn't mention this yesterday, but probably the next 08/11 patch can > have the same problem. But this is a bit more complicated because send_sigio() > uses the same "type" both for do_each_pid_task() and as an argument passed to > do_send_sig_info().
perhaps it can simply do
if (type <= PIDTYPE_TGID) { rcu_read_lock(); p = pid_task(pid, PIDTYPE_PID); send_sigio_to_task(p, fown, fd, band, type); rcu_read_unlock(); } else { read_lock(&tasklist_lock); do_each_pid_task(pid, type, p) { send_sigio_to_task(p, fown, fd, band, type); } while_each_pid_task(pid, type, p); read_unlock(&tasklist_lock); }
this way we also avoid tasklist_lock in F_OWNER_TID/F_OWNER_PID case.
To clarify, it is not that I think any sane application can do fcntl(F_OWNER_PID, thread_tid) but still this is a user-visible change we can easily avoid.
Oleg.
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