search for: sigchld

...39;s udb. I could have put them in seesion.c but I think session.c is getting to loaded with speicalied system codes. The same is true for pty.c. Maby it time to split out the code int seperate system modules in the openbsd-compat directiry. 4) Fixed a few minor issues with resetting SIGCHLD. If you permanently install a signal with mysingnal for SIGCHLD you don't need to reset it in the sigchld handler. You can get into a infinite signal loop if the sigchld handler does not reap the child win it is called if it reset the sigchld handler, it is a cray thing. 5) It i...

HP-UX 11 is looping on SIGCHLD/sigchld_handler2() when exiting a protocol 2 session apparently because we don't call wait before reinstalling the handler. Any thoughts on this issue or how to address it? serverloop.c from latest snapshots: void sigchld_handler2(int sig) { int save_errno = errno; debug("Received SIG...

...The code in question is in socket.c in start_accept_loop. The user is getting these warning messages: ----------------------------- Jul 8 12:56:59 ftp kernel: application bug: rsync(1051) has SIGCHLD set to SIG_IGN but calls wait(). Jul 8 12:56:59 ftp kernel: (see the NOTES section of 'man 2 wait'). Workaround activated. ----------------------------- I was able to reproduce that error with rsync server and...

Maybe this is a ssh problem - but are you aware of the general issue ? http://bugzilla.mindrot.org/show_bug.cgi?id=182 Summary: ssh should still force SIGCHLD to be SIG_DFL when calling ssh-rand-helper Product: Portable OpenSSH Version: 3.1p1 Platform: ix86 OS/Version: All Status: NEW Severity: normal Priority: P3 Component: ssh AssignedTo: openss...

http://bugzilla.mindrot.org/show_bug.cgi?id=271 Summary: SSHD should unblock SIGCHLD - POSIX signal blocks survive exec() Product: Portable OpenSSH Version: -current Platform: Other OS/Version: other Status: NEW Severity: enhancement Priority: P2 Component: sshd AssignedTo:...

http://bugzilla.mindrot.org/show_bug.cgi?id=182 Summary: ssh should still force SIGCHLD to be SIG_DFL when calling ssh-rand-helper Product: Portable OpenSSH Version: 3.1p1 Platform: ix86 OS/Version: All Status: NEW Severity: normal Priority: P3 Component: ssh AssignedTo: openss...

On Saturday, November 2, 2019 10:40:45 PM EET Stephan Bosch <stephan at rename-it.nl> wrote: > I think we already know about this issue (tracked as DOP-942). It > apparently happens because qmail masks the SIGCHLD signal while Dovecot > doesn't unmask it before waiting for children. You're right. Isn't this a simple fix - a call to sigprocmask ? This should not be a problem in qmail-lspawn/qmail-local as their code has not been changed for years. So there should have been a breaking change i...

...nd networks. Very occasionally we've seen the situation where the ssh client and server are both stuck in select, both selecting on only the tcp socket of the connection, and with no timeout. No children of sshd remain (even as zombies), and it has no other interesting open fds. If you send a SIGCHLD to the hung sshd, it wakes up and exits. As far as I can see, there's a race condition in wait_until_can_do_something(), both in RedHat 2.5.2p2-5 and in the latest CVS sources. It tests child_terminated, and sets a non-zero timeout if so, before calling select(). However, there is a very small...

...e: /home/markus/cvs/ssh/serverloop.c,v retrieving revision 1.82 diff -u -r1.82 serverloop.c --- serverloop.c 10 Oct 2001 22:18:47 -0000 1.82 +++ serverloop.c 11 Oct 2001 18:06:33 -0000 @@ -92,6 +92,45 @@ /* prototypes */ static void server_init_dispatch(void); +/* + * we write to this pipe if a SIGCHLD is caught in order to avoid + * the race between select() and child_terminated + */ +static int notify_pipe[2]; +static void +notify_setup(void) +{ + if (pipe(notify_pipe) < 0) { + error("pipe(notify_pipe) failed %s", strerror(errno)); + notify_pipe[0] = -1; /* read end */ + notify_...

Hi What if you have sysv signals (i.e. signal is restored when handler is called) and child process exits here? Zombie will be left, because SIGCHLD is ignored at that point. Shouldn't signal be before waitpid? Mikulas static void main_sigchld_handler(int sig) { int save_errno = errno; pid_t pid; int status; while ((pid = waitpid(-1, &status, WNOHANG)) > 0 || (pid < 0 && errno...

Peter Dimitrov and myself were debugging a very peculiar bug when libguestfs is run as a plugin from collectd: https://www.redhat.com/archives/libguestfs/2018-November/thread.html#00023 The long story short is that collectd leaks SIGCHLD == SIG_IGN setting into plugins: https://www.redhat.com/archives/libguestfs/2018-November/msg00095.html This means that any plugin that does the usual pattern of: pid = fork (); ... if (waitpid (pid, NULL, 0) == -1) { perror ("waitpid"); exit (EXIT_FAILURE); } will f...

So, we just found some ugly behaviour of OpenSSH on Solaris. Sometimes, it seems, sshd gets started with SIGCHLD blocked, this, apparently, being the setting of sshd's parent (a shell no doubt); signal blocking is inherited across exec*(). I don't know exactly which shell, or what really is at fault, but it happens. The problem is that the code in collect_children() first blocks SIGCHLD (SIGCLD) and...

http://bugzilla.mindrot.org/show_bug.cgi?id=79 Summary: A race with select() in SIGCHLD handling causes hangs occasionally Product: Portable OpenSSH Version: 3.0.2p1 Platform: All URL: http://marc.theaimsgroup.com/?l=openssh-unix- dev&m=100454673601558&w=2 OS/Version: All...

...ng before the crash (just the log of mirrors sync). I 'straced' the rsync process and have the following outputs : select(6, [4 5], NULL, NULL, NULL) = 1 (in [5]) accept(5, {sa_family=AF_INET, sin_port=htons(37870), sin_addr=inet_addr("xxxxxxxxxxxx")}, [16]) = 3 rt_sigaction(SIGCHLD, {0x80768c0, [], SA_NOCLDSTOP}, NULL, 8) = 0 clone(child_stack=0, flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD, child_tidptr=0xb7e196f8) = 7117 close(3) = 0 select(6, [4 5], NULL, NULL, NULL) = 1 (in [4]) accept(4, {sa_family=AF_INET6, sin6_port=htons(55...

...the log. When running it as a service (after restart). Here is what the output from strace -p $PID_OF_ASTERISK [root at localhost ~]# strace -p 1470 Process 1470 attached wait4(-1, [{WIFEXITED(s) && WEXITSTATUS(s) == 0}], 0, NULL) = 2505 rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0 --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=2505, si_status=0, si_utime=0, si_stime=0} --- wait4(-1, 0x7ffd2cbd4490, WNOHANG, NULL) = -1 ECHILD (No child processes) rt_sigreturn() = 0 rt_sigaction(SIGINT, {SIG_IGN, [], SA_RESTORER, 0x7f1a0245b250}, {SIG_IGN, [], SA_RESTOR...

...ones <rjones@redhat.com> wrote: > Peter Dimitrov and myself were debugging a very peculiar bug when > libguestfs is run as a plugin from collectd: > > https://www.redhat.com/archives/libguestfs/2018-November/thread.html#00023 > > The long story short is that collectd leaks SIGCHLD == SIG_IGN setting > into plugins: > > https://www.redhat.com/archives/libguestfs/2018-November/msg00095.html > > This means that any plugin that does the usual pattern of: > > pid = fork (); > ... > if (waitpid (pid, NULL, 0) == -1) { > perror ("waitp...

...PM +0000, Richard W.M. Jones wrote: > Peter Dimitrov and myself were debugging a very peculiar bug when > libguestfs is run as a plugin from collectd: > > https://www.redhat.com/archives/libguestfs/2018-November/thread.html#00023 > > The long story short is that collectd leaks SIGCHLD == SIG_IGN setting > into plugins: > > https://www.redhat.com/archives/libguestfs/2018-November/msg00095.html > > This means that any plugin that does the usual pattern of: > > pid = fork (); > ... > if (waitpid (pid, NULL, 0) == -1) { > perror ("wa...

...r to have had any ill effects. Thanks, Paul ------- Forwarded Message Date: Tue, 18 Sep 2001 16:49:40 -0700 From: Paul Menage <pmenage at ensim.com> To: mouring at etoh.eviladmin.org cc: Paul Menage <pmenage at ensim.com>, openssh-unix-dev at mindrot.org Subject: Re: SIGCHLD race condition? > >Can you test against 2.9p2 or the current snapshots.. There has been some >SIGCHLD changes since 2.5.2pX series. > The signal handling strategy has changed, but the race condition in wait_until_can_do_something(), between checking child_terminated and calling selec...

...ommit;h=de74268fc82f0b99743904f5d18a69ad690eec2c Author: Herbert Xu <herbert at gondor.apana.org.au> AuthorDate: Mon, 7 May 2018 00:40:34 +0800 Committer: Ben Hutchings <ben at decadent.org.uk> CommitDate: Fri, 25 Jan 2019 02:57:21 +0000 [klibc] jobs - Do not block when waiting on SIGCHLD Because of the nature of SIGCHLD, the process may have already been waited on and therefore we must be prepared for the case that wait may block. So ensure that it doesn't by using WNOHANG. Furthermore, multiple jobs may have exited when gotsigchld is set. Therefore we need to wait until the...

...h=dfe960aa216a4495cf926fac099caacabc5684e3 Author: Herbert Xu <herbert at gondor.apana.org.au> AuthorDate: Mon, 7 May 2018 00:40:34 +0800 Committer: Ben Hutchings <ben at decadent.org.uk> CommitDate: Sat, 28 Mar 2020 21:42:55 +0000 [klibc] dash: jobs - Do not block when waiting on SIGCHLD [ dash commit 9e5cd41d9605e4caaac3aacdc0482f6ee220a298 ] Because of the nature of SIGCHLD, the process may have already been waited on and therefore we must be prepared for the case that wait may block. So ensure that it doesn't by using WNOHANG. Furthermore, multiple jobs may have exited w...