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From: Skip Tavakkolian <skip.tavakkolian@gmail.com>
To: 9fans <9fans@9fans.net>
Subject: Re: [9fans] syscall silently kill processes
Date: Fri, 17 Jun 2022 09:08:57 -0700	[thread overview]
Message-ID: <CAJSxfmJsAUURUZzE2OcHxNa2=ec7dnOudK-3q82msbjG2F0VFw@mail.gmail.com> (raw)
In-Reply-To: <9e922645a598c69ba14b74e18e8669cc068e9717.camel@gmail.com>

interesting catch. it seems to be a tunable limit.

% grep NFN /sys/src/libthread/note.c
#define NFN 33
static int (*onnote[NFN])(void*, char*);
static int onnotepid[NFN];
for(i=0; i<NFN; i++)
return i<NFN;
for(i=0; i<NFN; i++){
if(i==NFN){

On Fri, Jun 17, 2022 at 8:08 AM <andrey100100100@gmail.com> wrote:
>
> В Пт, 17/06/2022 в 08:11 -0600, Jacob Moody пишет:
> > On 6/17/22 07:46, Thaddeus Woskowiak wrote:
> > > I believe threadnotify() should be called from threadmain() to
> > > properly register the handler in the rendez group
> >
> > This is incorrect, according to thread(2):
> >
> > "The thread library depends on all procs
> > being in the same rendezvous group"
>
>
> From sleep(2):
>
>     Alarm causes an alarm note (see notify(2)) to be sent to the
>     invoking process after the number of milliseconds given by
>     the argument.
>
> Mean to be sent only to the invoking process, NOT to the process group.
>
> >
> > The issue here is that your note handler has to call noted,
> > you are returning from the handler without actually resuming the
> > program.
> > You either need to call noted(NCONT) to resume execution or
> > noted(NDFLT)
> > to stop execution.
> >
> > An excerpt from notify(2):
> >
> > "A notification handler must finish either by exiting the
> > program or by calling noted; if the handler returns the
> > behavior is undefined and probably erroneous."
> >
> > So you are indeed observing undefined behavior.
> >
>
> With:
>
> ------------------------------------
> static int
> handler_alarm(void *, char *msg)
> {
>         if(strstr(msg, "alarm")){
>                 noted(NCONT);
>                 return 1;
>         }
>
>         return 0;
> }
> ------------------------------------
>
> result the same:
>
> cpu% 6.out | grep end | wc -l
>      33
>
>
> And noted(NCONT) may be needed, when process recieved many (2 and more)
> notes at once.
>
> May be something wrong  with interrupted an incomplete  system call?
>
>
> >
> > Hope this helps,
> > moody
> >
> 
> 
> Regards,
> Andrej
> 

------------------------------------------
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  reply	other threads:[~2022-06-17 16:09 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-17  9:37 andrey100100100
2022-06-17 13:46 ` Thaddeus Woskowiak
2022-06-17 14:11   ` Jacob Moody
2022-06-17 14:39     ` Thaddeus Woskowiak
2022-06-17 15:06     ` andrey100100100
2022-06-17 16:08       ` Skip Tavakkolian [this message]
2022-06-17 16:11         ` Skip Tavakkolian
2022-06-17 16:16           ` Skip Tavakkolian
2022-06-17 17:42             ` adr
2022-06-17 16:11       ` Jacob Moody
2022-06-17 18:48         ` andrey100100100
2022-06-17 19:28           ` Jacob Moody
2022-06-17 21:15           ` adr
2022-06-18  6:40             ` andrey100100100
2022-06-18  8:37               ` adr
2022-06-18  9:22                 ` adr
2022-06-18 12:53                   ` Jacob Moody
2022-06-18 22:03                     ` andrey100100100
2022-06-19  5:54                     ` adr
2022-06-19  6:13                       ` Jacob Moody
2022-06-18 22:22                   ` andrey100100100
2022-06-18 16:57                 ` andrey100100100
2022-06-19  2:40                   ` adr
2022-06-19  5:01                     ` adr
2022-06-19  8:52                       ` andrey100100100
2022-06-19 10:32                         ` adr
2022-06-19 11:40                           ` andrey100100100
2022-06-19 12:01                             ` andrey100100100
2022-06-19 15:10                           ` andrey100100100
2022-06-19 16:41                             ` adr
2022-06-19 21:22                               ` andrey100100100
2022-06-19 21:26                                 ` andrey100100100
2022-06-20  4:41                                 ` adr
2022-06-20  5:39                                   ` andrey100100100
2022-06-20  5:59                                   ` adr
2022-06-20 15:56                                     ` andrey100100100
2022-06-20 22:29                                       ` Skip Tavakkolian
2022-06-21  7:07                                         ` andrey100100100
2022-06-21 11:26                                           ` adr
2022-06-21 13:03                                             ` andrey100100100
2022-06-21 13:22                                               ` adr
2022-06-28 15:28                                                 ` adr
2022-06-28 16:43                                                   ` ori
2022-06-28 18:19                                                   ` adr
2022-06-28 18:28                                                     ` adr
2022-06-28 19:09                                                   ` andrey100100100
2022-06-28 19:42                                                     ` adr
2022-06-29 13:14                                                       ` adr
2022-06-21 13:47                                             ` andrey100100100
2022-06-21  7:22                                         ` adr

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