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* [musl] Potential deadlock in pthread_kill()
@ 2020-06-30  4:19 Hydro Flask
  2020-06-30  4:43 ` Rich Felker
  0 siblings, 1 reply; 13+ messages in thread
From: Hydro Flask @ 2020-06-30  4:19 UTC (permalink / raw)
  To: musl

Hello all,

Noticed something while reading some code today. pthread_kill() is 
specified by POSIX to be async signal safe but I noticed that in musl's 
implementation if a signal occurs while the "killlock" is held and the 
signal handler calls pthread_kill() on the same target thread, a 
deadlock will occur. Is this intentional?

         int pthread_kill(pthread_t t, int sig)
         {
                 int r;
                 LOCK(t->killlock);
                 r = t->tid ? -__syscall(SYS_tkill, t->tid, sig)
                         : (sig+0U >= _NSIG ? EINVAL : 0);
                 UNLOCK(t->killlock);
                 return r;
         }

Thank you for your attention.

Hydro

^ permalink raw reply	[flat|nested] 13+ messages in thread

end of thread, other threads:[~2020-07-06 22:38 UTC | newest]

Thread overview: 13+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-06-30  4:19 [musl] Potential deadlock in pthread_kill() Hydro Flask
2020-06-30  4:43 ` Rich Felker
2020-06-30  6:19   ` Hydro Flask
2020-06-30  9:26     ` Rich Felker
2020-06-30 14:58       ` Markus Wichmann
2020-06-30 16:28         ` Hydro Flask
2020-06-30 19:28           ` Dmitry Samersoff
2020-06-30 19:54             ` Rich Felker
2020-06-30 21:00               ` Hydro Flask
2020-07-06 22:00                 ` Rich Felker
2020-07-06 22:14                   ` Hydro Flask
2020-07-06 22:22                     ` Rich Felker
2020-07-06 22:37                       ` Hydro Flask

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