Messages in this thread | ![/](/images/icornerl.gif) | | Subject | Re: FW: am-utils or kernel bug ? Seems to be kernel or glibc bug... | From | Nicolas Turro <> | Date | 14 May 2003 10:27:41 +0200 |
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On Wed, 2003-05-14 at 04:23, Ion Badulescu wrote: > > > i am running Redhat 9.0 ( kernel 2.4.20 ) > > > and am-utils (am-utils-6.0.9-2) (because i need the browsing feature > > > that automount doen't support). > > > > > > Unfortunatelly, amd sometimes hangs at boot time during its > > > initialization (/etc/rc.d/init.d/amd ). > > > I can reproduce this bug with /etc/rc.d/init.d/amd start / stop > > > sequences, sometimes the start hangs sometimes it works. > > > This bug occurs on ALL RedHat 9.0 boxes we have (7 PC with totally > > > different hardware).
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> > > [root@redhat-serv root]# strace -p 2454 > > > futex(0x4212e1c8, FUTEX_WAIT, -2, NULL <unfinished ...> > > > > > > > > > [root@redhat-serv root]# strace -p 2455 > > > select(1024, [4 5 6 7], NULL, NULL, {932, 980000} <unfinished ...> > > I'll be damned if I understand what the futex is used for here. But since > that's the parent amd, presumably it's waiting for the child to complete > something, probably a mount. > > As for the second trace, we need to know what the four filedescriptors are > for. 'lsof -p 2455' should shed some light... > > I suspect either a bug in glibc (likely), or a bug in the way amd uses > some Unix primitives and which just happen to work on older glibc's (less > likely). It's going to be rather hard to debug, however, if we can't > reproduce it locally. > > Another suggestion I have is this: boot into an older kernel without futex > support (2.4.18-27.7.x should do just fine, ignore the missing > dependencies because they are not fatal). Glibc will adjust to the older > kernel and use other mechanisms, and we'll see if the hang still occurs. > Basically, since futexes were back-ported by Red Hat from 2.5 kernels, I > suspect there might be some bugs or races in there, and this test would > help to clear it out.
You were right, Ion, switching to a RH8 kernel ( 2.4.18-14 ) , solved the issue. I cannot reproduce this futex bug on the father process...
Who should i contact in order to correct things ?
-- Nicolas Turro <Nicolas.Turro@sophia.inria.fr> INRIA
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