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
>
------------------------------------------
9fans: 9fans
Permalink: https://9fans.topicbox.com/groups/9fans/Tfa6823048ad90a21-Mb2e0af1ac4067b7f4649d000
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next prev parent 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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