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From: Thaddeus Woskowiak <tswoskowiak@gmail.com>
To: 9fans <9fans@9fans.net>
Subject: Re: [9fans] syscall silently kill processes
Date: Fri, 17 Jun 2022 09:46:49 -0400	[thread overview]
Message-ID: <CAG3JMtb6LuPc8G82iMg6SLDJ_U7-CYb1-x0_NR3C-zmGQbLudw@mail.gmail.com> (raw)
In-Reply-To: <79286caa2ca77ea9b9a1cd64918bdc5f28c8f180.camel@gmail.com>

I believe threadnotify() should be called from threadmain() to
properly register the handler in the rendez group.

On Fri, Jun 17, 2022 at 5:39 AM <andrey100100100@gmail.com> wrote:
> 
> Hi all!
> 
> Strange behavior of syscall 'read' with signal 'alarm' in followed
> simple program (ip/port - not matter):
> 
> -----------------------------------------------------------------------
> #include <u.h>
> #include <libc.h>
> #include <thread.h>
> 
> static int
> handler_alarm(void *, char *msg)
> {
>         if(strstr(msg, "alarm"))
>                 return 1;
> 
> return 0;
> }
> 
> static void
> proc_udp(void *)
> {
>         char resp[512];
>         char req[] = "request";
>         int fd;
> 
> threadnotify(handler_alarm, 1);
> 
> if((fd = dial("udp!185.157.221.201!5678", nil, nil, nil)) >=
> 0){
>         if(write(fd, req, strlen(req)) == strlen(req)){
>                 fprint(1, "start\n");
>                 alarm(2000);
>                 read(fd, resp, sizeof(resp));
>                 alarm(0);
>                 fprint(1, "end\n");
>         }
>         close(fd);
> }
> 
> threadexits(nil);
> }
> 
> int mainstacksize = 5242880;
> 
> void
> threadmain(int argc, char *argv[])
> {
>         for(int i = 0; i < 80; i++){
>                 proccreate(proc_udp, nil, 10240);
>         }
> 
> sleep(5000);
> threadexitsall(nil);
> }
> -----------------------------------------------------------------------
> 
> cpu% 6.out | grep end | wc -l
>      33
> 
> sometimes little more or less
> but
> 
> cpu% 6.out | grep start | wc -l
>      80
> 
> always.
> 
> Testing on Miller's RPi and 9front (amd64 & RPi 2)
> 
> Why does read() kill process?
> Why not always?
> Why number of 'ended' processes arond 33?
> This is normal behavior?
> How to fix the program so that the processes do not lost?
> 
> Can someone point me in the right direction?
> 
> Thanks!
> Andrey

------------------------------------------
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  reply	other threads:[~2022-06-17 13:46 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 [this message]
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
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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