amd64/129238: [panic] System randomly panics

[Jurriaan Nijkamp]

The following reply was made to PR amd64/129238; it has been noted by GNATS.

From: "Jurriaan Nijkamp" <alias at jurrie.net>
To: bug-followup at FreeBSD.org,
 alias at jurrie.net
Cc:  
Subject: Re: amd64/129238: [panic] System randomly panics
Date: Tue, 2 Dec 2008 08:13:22 +0100 (CET)

 After another crash yesterday, I got a new dump which, according to
 someone who knows what he's talking about, is actually useful. He also
 said the problem may lie with faulty memory, but I must say I did a
 memtest86+ test last week which said my memory was working perfectly.
 
 I am pasting the output of kgdb below.
 
 ---- output of kgdb kernel.debug /var/crash/vmcore.9 ----
 
 [GDB will not be able to debug user-mode threads:
 /usr/lib/libthread_db.so: Unde                                 fined
 symbol "ps_pglobal_lookup"]
 GNU gdb 6.1.1 [FreeBSD]
 Copyright 2004 Free Software Foundation, Inc.
 GDB is free software, covered by the GNU General Public License, and you are
 welcome to change it and/or distribute copies of it under certain conditions.
 Type "show copying" to see the conditions.
 There is absolutely no warranty for GDB.  Type "show warranty" for details.
 This GDB was configured as "amd64-marcel-freebsd".
 
 Unread portion of the kernel message buffer:
 
 
 Fatal trap 12: page fault while in kernel mode
 cpuid = 0; apic id = 00
 fault virtual address   = 0xffff800004003908
 fault code              = supervisor read data, page not present
 instruction pointer     = 0x8:0xffffffff8072436c
 stack pointer           = 0x10:0xffffffffae6d2a00
 frame pointer           = 0x10:0x4000000000
 code segment            = base 0x0, limit 0xfffff, type 0x1b
                         = DPL 0, pres 1, long 1, def32 0, gran 1
 processor eflags        = interrupt enabled, resume, IOPL = 0
 current process         = 5551 (sed)
 trap number             = 12
 panic: page fault
 cpuid = 0
 Uptime: 4h42m45s
 Physical memory: 2035 MB
 Dumping 311 MB: 296 280 264 248 232 216 200 184 168 152 136 120 104 88 72
 56 40                                  24 8
 
 #0  doadump () at pcpu.h:194
 194             __asm __volatile("movq %%gs:0,%0" : "=r" (td));
 (kgdb) bt
 #0  doadump () at pcpu.h:194
 #1  0x0000000000000004 in ?? ()
 #2  0xffffffff804776c9 in boot (howto=260)
     at /usr/src/sys/kern/kern_shutdown.c:409
 #3  0xffffffff80477acd in panic (fmt=0x104 <Address 0x104 out of bounds>)
     at /usr/src/sys/kern/kern_shutdown.c:563
 #4  0xffffffff8072edd4 in trap_fatal (frame=0xffffff00018bc9c0,
     eva=18446742974225594576) at /usr/src/sys/amd64/amd64/trap.c:724
 #5  0xffffffff8072f1a5 in trap_pfault (frame=0xffffffffae6d2950, usermode=0)
     at /usr/src/sys/amd64/amd64/trap.c:641
 #6  0xffffffff8072fae8 in trap (frame=0xffffffffae6d2950)
     at /usr/src/sys/amd64/amd64/trap.c:410
 #7  0xffffffff8071575e in calltrap ()
     at /usr/src/sys/amd64/amd64/exception.S:169
 #8  0xffffffff8072436c in pmap_remove_pages (pmap=0xffffff0001ab7778)
     at /usr/src/sys/amd64/amd64/pmap.c:388
 #9  0xffffffff80688238 in vmspace_exit (td=0xffffff00018bc9c0)
     at /usr/src/sys/vm/vm_map.c:404
 #10 0xffffffff804577ac in exit1 (td=0xffffff00018bc9c0, rv=0)
     at /usr/src/sys/kern/kern_exit.c:294
 #11 0xffffffff80458b5e in sys_exit (td=Variable "td" is not available.
 ) at /usr/src/sys/kern/kern_exit.c:98
 #12 0xffffffff8072f427 in syscall (frame=0xffffffffae6d2c70)
     at /usr/src/sys/amd64/amd64/trap.c:852
 #13 0xffffffff8071596b in Xfast_syscall ()
     at /usr/src/sys/amd64/amd64/exception.S:290
 #14 0x00000008006a8b3c in ?? ()
 Previous frame inner to this frame (corrupt stack?)
 
 ---- end kgdb output ----
 
 After this, following instructions given to me, I jumped to step #8 and
 did a 'list' command:
 
 ---- followup output ----
 
 (kgdb) frame 8
 #8  0xffffffff8072436c in pmap_remove_pages (pmap=0xffffff0001ab7778)
     at /usr/src/sys/amd64/amd64/pmap.c:388
 388             return (PTmap + ((va >> PAGE_SHIFT) & mask));
 (kgdb) list
 383     PMAP_INLINE pt_entry_t *
 384     vtopte(vm_offset_t va)
 385     {
 386             u_int64_t mask = ((1ul << (NPTEPGSHIFT + NPDEPGSHIFT +
 NPDPEPGSHIFT + NPML4EPGSHIFT)) - 1);
 387
 388             return (PTmap + ((va >> PAGE_SHIFT) & mask));
 389     }
 390
 391     static __inline pd_entry_t *
 392     vtopde(vm_offset_t va)
 
 ---- end followup output ----