Bug 103406 - auto-modprobe triggers 'wait() while SIGCHLD ignored' warning
auto-modprobe triggers 'wait() while SIGCHLD ignored' warning
Product: Fedora
Classification: Fedora
Component: kernel (Show other bugs)
All Linux
medium Severity medium
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Assigned To: Dave Jones
Brian Brock
Depends On:
Blocks: CambridgeTarget
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Reported: 2003-08-29 16:44 EDT by Bill Nottingham
Modified: 2015-01-04 17:03 EST (History)
2 users (show)

See Also:
Fixed In Version: 2.3-10
Doc Type: Bug Fix
Doc Text:
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Clone Of:
Last Closed: 2005-01-14 00:04:14 EST
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RHEL 7.3 requirements from Atomic Host:
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Description Bill Nottingham 2003-08-29 16:44:09 EDT
Comment 1 David Woodhouse 2003-08-29 18:03:16 EDT
What version of bluez-utils? 

* Sun Apr 27 2003 David Woodhouse <dwmw2@redhat.com> 2.3-3
- Unignore SIGCHLD before starting pin helper, report its return code

If it ain't that, what do you do to provoke it?
Comment 2 Bill Nottingham 2003-08-29 18:09:18 EDT

Nothing in particular; I get that message from somewhere in the startup sequence
(there is no bluetooth hardware on this box, AFAIK.)
Comment 3 David Woodhouse 2003-08-29 18:15:22 EDT
OK; will investigate. No calls to wait() or popen() in the source though -- it's
got to be a library; I suspect dbus. Shame the kernel doesn't give the address
of the offending syscall.
Comment 4 Bill Nottingham 2003-08-29 18:24:09 EDT
        sa.sa_handler = SIG_IGN;
        sigaction(SIGCHLD, &sa, NULL);
        sigaction(SIGPIPE, &sa, NULL);
(in main.c)
Comment 5 David Woodhouse 2003-08-30 05:40:10 EDT
Well yes, but that part's fine as long as you don't subsequently call wait().
And I can't see where we're calling wait() from. 

But since we don't actually have any children we care about, apart from the ones
for which I've already _explicitly_ made it unignore SIGCHLD, I suppose we can
just stop ignoring SIGCHLD altogether.

At least if people bitch at me about that they'll be able to tell me the name of
the zombies to which they object :)

2.3-10 ought to make this go away. Reopen if it doesn't.
Comment 6 David Woodhouse 2003-08-30 05:49:10 EDT
Oh, actually that's crap; I see zombies already. Will look again on Monday.
Comment 7 David Woodhouse 2003-08-30 10:19:26 EDT
OK, I found it and it's not bluez-utils' fault. Patch reverted in 2.3-11.

We ignore SIGCHLD, we do something which triggers a module autoload. Kernel
helpfully calls wait() for us, to wait for the modprobe to finish.

Reassigning to kernel.
Comment 8 Dave Jones 2004-11-19 20:59:39 EST
fixed in latest kernels ?
Comment 9 Dave Jones 2005-01-14 00:04:14 EST
ye olde bug. assuming fixed.

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