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On Tue, Jun 22, Steve Munroe wrote: > Thorsten Kukuk <kukuk@suse.de> wrote on 06/22/2004 11:22:56 PM: > > > On Tue, Jun 22, Jakub Jelinek wrote: > > > > > On Tue, Jun 22, 2004 at 11:50:59PM +0200, Thorsten Kukuk wrote: > > > > > > > > Hi, > > > > > > > > I got the following test program. I know, it is very ugly and there > > > > are a lot of things somebody should not do, but this is something > > > > what programs like sshd are doing. > > > > > > Then they should be fixed. Neither syslog, nor printf, nor fflush > > > are supposed to be async-signal safe, nor they actually are in glibc. > > > > Yes, but the problem is: Nearly every daemon on a Linux system is > > calling syslog() in a signal handler and it seems to be very easy > > to deadlock them on every Linux system running glibc/NPTL. While > > there seems to be no other system with the same problem. > > > > Then what has change from glibc-2.3.3 (RHEL 3) until now? Because I have > not seen this problem before. The test case also deadlocks on a RHEL 3 machine very fast. > I have reviewed all the changes to > lowlevellock.h since and I do not see any change that would effect this. In > fact your test case should show that same hang there. The difference is: glibc with linuxthreads compiled only uses the locking, if the program is linked against pthread. glibc with NPTL compiled always uses locking (__libc_lock_lock always calls lll_lock). Uli, Jakub, is this really necessary? Wouldn't it be better to add the one extra compare? > Have the daemon's changed recently to add the syslog() call to the signal > handler? No, this is very, very old. Thorsten -- Thorsten Kukuk http://www.suse.de/~kukuk/ kukuk@suse.de SuSE Linux AG Maxfeldstr. 5 D-90409 Nuernberg -------------------------------------------------------------------- Key fingerprint = A368 676B 5E1B 3E46 CFCE 2D97 F8FD 4E23 56C6 FB4B
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