Re: Filesystem wedges caused by r251446

On Thu, Jul 04, 2013 at 09:21:11AM +0200, Ian FREISLICH wrote:
> Hi
> 
> I've been experiencing process wedges writing files.  It occurs
> reliably under "heavy" IO activity, perhaps with large files but
> I'm not entirely sure what the trigger is.  The symptom is that
> during an installworld, it reliably hangs the install process on
> /usr/bin/clang (sometimes it hangs earlier at the mtree on /usr)
> 
> The problem leaves the filesystem in a state where it cannot be
> cleanly unmounted.  A binary search pins the offending commit on
> r251446.
> 
> The major differences between the working system and the broken one
> are, CPU, RAM and arch (i386/amd64) they are otherwise identical
> Dell R200 servers.
> 
> Working:
> CPU: Intel(R) Core(TM)2 Duo CPU     E4600  _at_ 2.40GHz (2400.14-MHz 686-class CPU)
> RAM:	2G
> Arch:	i386
> 
> Broken:
> CPU: Intel(R) Core(TM)2 Duo CPU     E7300  _at_ 2.66GHz (2666.82-MHz K8-class CPU)
> RAM: 	4G
> Arch:	amd64
> 
> The compiler, gcc, clang (trunk or release) has no effect.
> 
> Working CPU:
> FreeBSD 10.0-CURRENT #6 r252384: Sun Jun 30 08:36:31 SAST 2013
>     ianf_at_fw2:/usr/obj/usr/src/sys/FIREWALL i386
> FreeBSD clang version 3.3 (tags/RELEASE_33/final 183502) 20130610
> CPU: Intel(R) Core(TM)2 Duo CPU     E4600  _at_ 2.40GHz (2400.14-MHz 686-class CPU)
>   Origin = "GenuineIntel"  Id = 0x6fd  Family = 0x6  Model = 0xf  Stepping = 13
>   Features=0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,C
> MOV,PAT,PSE36,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE>
>   Features2=0xe39d<SSE3,DTES64,MON,DS_CPL,EST,TM2,SSSE3,CX16,xTPR,PDCM>
>   AMD Features=0x20100000<NX,LM>
>   AMD Features2=0x1<LAHF>
>   TSC: P-state invariant, performance statistics
> real memory  = 2147483648 (2048 MB)
> avail memory = 2076581888 (1980 MB)
> 
> 
> Broken on:
> FreeBSD 10.0-CURRENT #19 r251445: Thu Jul  4 08:39:21 SAST 2013
>     ianf_at_fw1:/usr/obj/usr/src/sys/FIREWALL amd64
> FreeBSD clang version 3.3 (trunk 178860) 20130405
> CPU: Intel(R) Core(TM)2 Duo CPU     E7300  _at_ 2.66GHz (2666.82-MHz K8-class CPU)
>   Origin = "GenuineIntel"  Id = 0x10676  Family = 0x6  Model = 0x17  Stepping = 6
>   Features=0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE>
>   Features2=0x8e39d<SSE3,DTES64,MON,DS_CPL,EST,TM2,SSSE3,CX16,xTPR,PDCM,SSE4.1>
>   AMD Features=0x20100800<SYSCALL,NX,LM>
>   AMD Features2=0x1<LAHF>
>   TSC: P-state invariant, performance statistics
> real memory  = 4294967296 (4096 MB)
> avail memory = 3970727936 (3786 MB)

Care to provide any useful information ?

http://www.freebsd.org/doc/en_US.ISO8859-1/books/developers-handbook/kerneldebug-deadlocks.html