Jeff: Nice idea but inapplicable in this case. This hang is more like the compiler losing track of the stack depth and returning from a function to never-never land. By the time anything breaks the CPU is so far away from the cause that backtracking is not possible. And many times nothing breaks -- it just keeps executing in the pasture and can't be interrupted -- or it kills the debugger stub, or some such.
-- Dave Jeff Goldszer wrote: >Here is a "tunnel view" approach troubleshooting this SMP issue and possibly get more >information on this problem. > >I call this a tunnel view approach because it is assuming the hang is occurring >because of Deadlock on a SMP Lock. > >Modify the code LiS Locking code to busy loop (trylock) instead of calling the lock >macro. The busy loop will loop for some period of time after which it will assume a >hang and printout the thread trying to catch the lock and the thread that owns the >lock to the console. > >The approach make a lot of assumptions but in some circumstances can be useful. > > > > >Jeff Goldszer >Senior Software Engineer >AlebraTechnologies >65C Commodore Lane >West Babylon NY, 11704 >Phone: 631-321-5118 >FAX: 631-321-5119 > > -----Original Message----- >From: Dave Grothe [mailto:[EMAIL PROTECTED]] >Sent: Monday, May 20, 2002 12:06 PM >To: Linux STREAMS >Subject: [Linux-streams] LiS vs gcc 2.96 > >I have observed that gcc 2.96 contains a code optimization error that >causes mysterious system hangs when running LiS and certain driver >combinations that include interactions with the ldl driver. The hangs >are so bad that a 2 CPU SMP system with NMI watchdog timer enabled >cannot break into the loop. > >Due to the severity of the hang I was never able to get close enough to >the problem to pinpoint it. Therefore it cannot be usefully reported to >the gcc authors. > >The solution is to use -O2 instead of -O3 to build LiS and its included >drivers. The next published version of LiS will be configured to use >-O2. In the meantime if anyone is experiencing these sorts of problems, >try editing the LiS file config.mk directly and changing the >optimization level. > >I am uncertain whether it is necesary to build your STREAMS drivers with >-O2 rather than -O3. > >gcc 2.96 is distributed with both Red Hat 7.2 and 7.3. Both versions >have the problem. > >-- Dave > > >_______________________________________________ >Linux-streams mailing list >[EMAIL PROTECTED] >http://gsyc.escet.urjc.es/mailman/listinfo/linux-streams > _______________________________________________ Linux-streams mailing list [EMAIL PROTECTED] http://gsyc.escet.urjc.es/mailman/listinfo/linux-streams
