Re: About "panic: bufwrite: buffer is not busy???"

On Sun, Feb 20, 2011 at 10:30:52AM -0500, Mike Tancsa wrote:
> On 2/20/2011 9:33 AM, Andrey Smagin wrote:
> > On week -current I have same problem, my box paniced every 2-15 min. I resolve problem by next steps - unplug network connectors from 2 intel em (82574L) cards. I think last time that mpd5 related panic, but mpd5 work with another re interface interated on MB. I think it may be em related panic, or em+mpd5.
> 
> The latest panic I saw didnt have anything to do with em.  Are you sure
> your crashes are because of the nic drive ?
> 
> The latest I saw was on Friday.
> 
> # kgdb /usr/obj/usr/src/sys/router/kernel.debug vmcore.11
> (kgdb) bt
> #0  doadump () at pcpu.h:231
> #1  0xc04a51f9 in db_fncall (dummy1=1, dummy2=0, dummy3=-1063333856,
> dummy4=0xc6b9696c "") at /usr/src/sys/ddb/db_command.c:548
> #2  0xc04a55f1 in db_command (last_cmdp=0xc096f73c, cmd_table=0x0,
> dopager=1) at /usr/src/sys/ddb/db_command.c:445
> #3  0xc04a574a in db_command_loop () at /usr/src/sys/ddb/db_command.c:498
> #4  0xc04a764d in db_trap (type=12, code=0) at
> /usr/src/sys/ddb/db_main.c:229
> #5  0xc068ba7e in kdb_trap (type=12, code=0, tf=0xc6b96b94) at
> /usr/src/sys/kern/subr_kdb.c:546
> #6  0xc088056f in trap_fatal (frame=0xc6b96b94, eva=52) at
> /usr/src/sys/i386/i386/trap.c:937
> #7  0xc0880830 in trap_pfault (frame=0xc6b96b94, usermode=0, eva=52) at
> /usr/src/sys/i386/i386/trap.c:859
> #8  0xc0880d4a in trap (frame=0xc6b96b94) at
> /usr/src/sys/i386/i386/trap.c:532
> #9  0xc086716c in calltrap () at /usr/src/sys/i386/i386/exception.s:166
> #10 0xc0657a16 in uihold (uip=0x0) at /usr/src/sys/kern/kern_resource.c:1248
> #11 0xc0654ec9 in crcopy (dest=0xce3ee800, src=0xce3ee600) at
> /usr/src/sys/kern/kern_prot.c:1873
> #12 0xc0654fd1 in crcopysafe (p=0xc90cc810, cr=0xce3ee800) at
> /usr/src/sys/kern/kern_prot.c:1950
> #13 0xc0656d7f in seteuid (td=0xc9196b80, uap=0xc6b96cec) at
> /usr/src/sys/kern/kern_prot.c:615
> #14 0xc06985ff in syscallenter (td=0xc9196b80, sa=0xc6b96ce4) at
> /usr/src/sys/kern/subr_trap.c:315
> #15 0xc0880884 in syscall (frame=0xc6b96d28) at
> /usr/src/sys/i386/i386/trap.c:1061
> #16 0xc08671d1 in Xint0x80_syscall () at
> /usr/src/sys/i386/i386/exception.s:264
> #17 0x00000033 in ?? ()
> 
> (kgdb) frame 10
> #10 0xc0657a16 in uihold (uip=0x0) at /usr/src/sys/kern/kern_resource.c:1248
> 1248    {
> (kgdb) list
> 1243     * Place another refcount on a uidinfo struct.
> 1244     */
> 1245    void
> 1246    uihold(uip)
> 1247            struct uidinfo *uip;
> 1248    {
> 1249
> 1250            refcount_acquire(&uip->ui_ref);
> 1251    }
> 1252
> (kgdb) p *uip
> Cannot access memory at address 0x0
> (kgdb) p uip
> $1 = (struct uidinfo *) 0x0
> (kgdb)
Is this reproducable ?
What system version is it ?

Could you, please, go to frame 12 and show the output of "p *p",
"p *(p->p_ucred)" ?