Package: libc6 Version: 2.10.2-6 Severity: normal Whenever a program uses some kind of periodic timer (profiling, Haskell thread scheduler, ...) and makes a fork call that takes more time than the timer's interval, it enters and endless loop of clone syscalls being interrupted by the signal:
17:08:49.362528 clone(child_stack=0, flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD, child_tidptr=0xb765f938) = ? ERESTARTNOINTR (To be restarted) <0.031840> 17:08:49.394551 --- SIGPROF (Profiling timer expired) @ 0 (0) --- 17:08:49.394693 clone(child_stack=0, flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD, child_tidptr=0xb765f938) = ? ERESTARTNOINTR (To be restarted) <0.031548> 17:08:49.426335 --- SIGPROF (Profiling timer expired) @ 0 (0) --- 17:08:49.426475 clone(child_stack=0, flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD, child_tidptr=0xb765f938) = ? ERESTARTNOINTR (To be restarted) <0.031768> 17:08:49.458339 --- SIGPROF (Profiling timer expired) @ 0 (0) --- [... and so on ...] On my hardware, this happens for programs using more than 400 megs of memory (there's a linear dependence between memory used and the duration of clone). That means that any program that uses more than 400 megs of memory can't use fork and be profiled at the same time. A reproducer is at <http://store.lisk.in/tmp/perm/fork_profiling_hang.tar.gz>. `make all' generates a graph of the said dependence and `make hang' launches a test case that consumes 500 megs of memory and forks then. If that's not enough, just raise the number in the Makefile. -- System Information: Debian Release: squeeze/sid APT prefers testing APT policy: (990, 'testing'), (990, 'stable'), (500, 'unstable'), (500, 'stable'), (200, 'experimental') Architecture: i386 (i686) Kernel: Linux 2.6.32.7-lis-00002-gd18ac29 (SMP w/2 CPU cores) Locale: LANG=cs_CZ.UTF-8, LC_CTYPE=cs_CZ.UTF-8 (charmap=UTF-8) Shell: /bin/sh linked to /bin/bash Versions of packages libc6 depends on: ii libc-bin 2.10.2-6 Embedded GNU C Library: Binaries ii libgcc1 1:4.4.1-4 GCC support library Versions of packages libc6 recommends: ii libc6-i686 2.10.2-6 GNU C Library: Shared libraries [i Versions of packages libc6 suggests: ii debconf [debconf-2.0] 1.5.27 Debian configuration management sy ii glibc-doc 2.10.2-6 Embedded GNU C Library: Documentat ii locales 2.10.2-6 Embedded GNU C Library: National L -- debconf information: * glibc/upgrade: true glibc/disable-screensaver: glibc/restart-failed: * glibc/restart-services: -- Tomáš Janoušek, a.k.a. Liskni_si, http://work.lisk.in/ -- To UNSUBSCRIBE, email to debian-glibc-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/20100326161404.ga1...@notes.lisk.in