ptcwrite panic (with dump)

[Doug White]

Can you print *tp in frame 23, and then print tp->t_pgrp->pg_members?  The
code above should avoid the case of t_pgrp being NULL, but I wonder if
there is a race or if pg_members can end up uninitialized somewhere.

On Sun, 8 May 2005, Kris Kennaway wrote:

> Grr, truncation.
>
> Script started on Sun May  8 23:18:33 2005
> pointyhat# kgdb =07vmco=1B[16C=1B[Kkernel.debug.1 vmcore.1
> [GDB will not be able to debug user-mode threads: /usr/lib/libthread_db.s=
o: Undefined 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 conditi=
ons.
> Type "show copying" to see the conditions.
> There is absolutely no warranty for GDB.  Type "show warranty" for detail=
s.
> This GDB was configured as "i386-marcel-freebsd".
> #0  doadump () at pcpu.h:165
> 165=09pcpu.h: No such file or directory.
> =09in pcpu.h
> (kgdb) bt full
> #0  doadump () at pcpu.h:165
> No locals.
> #1  0xc045b605 in db_fncall (dummy1=3D1016, dummy2=3D0, dummy3=3D11, dumm=
y4=3D0xee3e38d4 "\f")
>     at ../../../ddb/db_command.c:531
> =09fn_addr =3D -1068399536
> =09args =3D {0 <repeats 11 times>}
> =09nargs =3D 11
> =09retval =3D 0
> =09func =3D (fcn_10args_t *) 0xc0518450 <doadump>
> =09t =3D 0
> #2  0xc045b392 in db_command (last_cmdp=3D0xc0753584, cmd_table=3D0x0, au=
x_cmd_tablep=3D0xc071f13c,
>     aux_cmd_tablep_end=3D0xc071f140) at ../../../ddb/db_command.c:349
> =09cmd =3D (struct command *) 0xc0724600
> =09t =3D 0
> =09modif =3D "\f\000\000\000=F8\003\000\000=F08>=EEf=F2h=C0=F8\003\000\00=
0=F8\003\000\000\r\000\000\000\0349>=EE=A5=F4h=C0\0049>=EE=F8\003\000\000\2=
00%\000\000\f\000\017\003\v\222U=C0x\000\000\000\200>u=C0\f\000\000\00049>=
=EE1=DAE=C0}=E8o=C0=B0=D6E=C0\000\000\000\000\020\000\000\000\f\000\000\000=
\200>u=C0=C6=CCE=C0\200>u=C086u=C0x\000\000\000\2309>=EE"
> =09addr =3D 1016
> =09count =3D 11
> =09have_addr =3D 0
> =09result =3D 0
> #3  0xc045b4a5 in db_command_loop () at ../../../ddb/db_command.c:455
> No locals.
> #4  0xc045d5e5 in db_trap (type=3D12, code=3D0) at ../../../ddb/db_main.c=
:221
> =09jb =3D {{_jb =3D {-297911912, -297911940, -297911860, 1, 12, -10691651=
78, 1, 12, -297911860,
>       -1068242440, -297911860, -1068273856}}}
> =09prev_jb =3D (void *) 0x0
> =09bkpt =3D 0
> #5  0xc0536fee in kdb_trap (type=3D0, code=3D0, tf=3D0xee3e3ab0) at ../..=
/../kern/subr_kdb.c:421
> =09did_stop_cpus =3D 1
> =09handled =3D -297911632
> #6  0xc06bbf06 in trap_fatal (frame=3D0xee3e3ab0, eva=3D0) at ../../../i3=
86/i386/trap.c:801
> =09code =3D 40
> ---Type <return> to continue, or q <return> to quit---
> =09type =3D 12
> =09ss =3D 40
> =09esp =3D 0
> =09softseg =3D {ssd_base =3D 0, ssd_limit =3D 1048575, ssd_type =3D 27, s=
sd_dpl =3D 0, ssd_p =3D 1,
>   ssd_xx =3D 11, ssd_xx1 =3D 1, ssd_def32 =3D 1, ssd_gran =3D 1}
> #7  0xc06bbbc2 in trap_pfault (frame=3D0xee3e3ab0, usermode=3D0, eva=3D8)=
 at ../../../i386/i386/trap.c:724
> =09va =3D 0
> =09vm =3D (struct vmspace *) 0x0
> =09map =3D 0x1
> =09rv =3D 1
> =09ftype =3D 1 '\001'
> =09td =3D (struct thread *) 0xc3a5ad80
> =09p =3D (struct proc *) 0xc3a593f8
> #8  0xc06bb78e in trap (frame=3D
>       {tf_fs =3D 8, tf_es =3D -1066074072, tf_ds =3D -1066074072, tf_edi =
=3D -1017107456, tf_esi =3D -1017107456, tf_ebp =3D -297911476, tf_isp =3D =
-297911588, tf_ebx =3D 20, tf_edx =3D 4, tf_ecx =3D 1, tf_eax =3D 0, tf_tra=
pno =3D 12, tf_err =3D 0, tf_eip =3D -1068146714, tf_cs =3D 32, tf_eflags =
=3D 66178, tf_esp =3D -1066031968, tf_ss =3D -1066384328}) at ../../../i386=
/i386/trap.c:414
> =09td =3D (struct thread *) 0xc3a5ad80
> =09p =3D (struct proc *) 0xc3a593f8
> =09sticks =3D 3228935364
> =09i =3D 0
> =09ucode =3D 0
> =09type =3D 12
> =09code =3D 0
> =09eva =3D 8
> #9  0xc06a683a in calltrap () at ../../../i386/i386/exception.s:139
> No locals.
> #10 0x00000008 in ?? ()
> No symbol table info available.
> #11 0xc0750028 in legacy_pcib_methods ()
> No symbol table info available.
> #12 0xc0750028 in legacy_pcib_methods ()
> ---Type <return> to continue, or q <return> to quit---
> No symbol table info available.
> #13 0xc3602c00 in ?? ()
> No symbol table info available.
> #14 0xc3602c00 in ?? ()
> No symbol table info available.
> #15 0xee3e3b4c in ?? ()
> No symbol table info available.
> #16 0xee3e3adc in ?? ()
> No symbol table info available.
> #17 0x00000014 in ?? ()
> No symbol table info available.
> #18 0x00000004 in ?? ()
> No symbol table info available.
> #19 0x00000001 in ?? ()
> No symbol table info available.
> #20 0x00000000 in ?? ()
> No symbol table info available.
> #21 0x0000000c in ?? ()
> No symbol table info available.
> #22 0x00000000 in ?? ()
> No symbol table info available.
> #23 0xc0555fe6 in ttyinfo (tp=3D0xc3602c00) at ../../../kern/tty.c:2565
> =09utime =3D {tv_sec =3D -1009844964, tv_usec =3D 1}
> =09stime =3D {tv_sec =3D -1066411237, tv_usec =3D 299}
> =09p =3D (struct proc *) 0x14
> =09pick =3D (struct proc *) 0xc050e9fa
> =09td =3D (struct thread *) 0x0
> =09stateprefix =3D 0xee3e3b4c "\200;>=EE=E4(U=C0"
> =09state =3D 0xc0704438 "../../../kern/tty.c"
> =09rss =3D 623
> =09load =3D 0
> =09pctcpu =3D -1017107456
> #24 0xc05528e4 in ttyinput (c=3D20, tp=3D0xc3602c00) at ../../../kern/tty=
=2Ec:626
> ---Type <return> to continue, or q <return> to quit---
> =09iflag =3D 11010
> =09lflag =3D 1483
> =09cc =3D (cc_t *) 0xc3602cbc "\004=FF=FF\177\027\025\022\b\003\034\032\0=
31\021\023\026\017\001"
> =09i =3D 0
> =09err =3D 0
> #25 0xc0559ef0 in ptcwrite (dev=3D0x0, uio=3D0xee3e3c70, flag=3D4) at lin=
edisc.h:122
> =09tp =3D (struct tty *) 0xc3602c00
> =09cp =3D (u_char *) 0xee3e3ba1 ""
> =09cc =3D 1
> =09locbuf =3D "\024\000\000\000\027=ACo=C0=CC;>=EE=FA=E9P=C0\200\210u=C0\=
001\000\000\000\033=DBo=C0+\001\000\000\000\177s=C0\000=ED\n=C6\200=AD=A5=
=C3=E4;>=EE*=B2N=C0\200\210u=C0\000\000\000\000\027=ACo=C0C\000\000\000\004=
<>=EE\200=A3u=C0V\005\000\000\003\201o=C0\034<>=EE:=E9P=C0\200=A3u=C0\b\000=
\000"
> =09cnt =3D 0
> =09error =3D 0
> #26 0xc04cf504 in devfs_write_f (fp=3D0xc5874d38, uio=3D0xee3e3c70, cred=
=3D0xc3c30e80, flags=3D0, td=3D0x1)
>     at ../../../fs/devfs/devfs_vnops.c:1367
> =09dev =3D (struct cdev *) 0xc60aed00
> =09error =3D 4
> =09ioflag =3D 4
> =09resid =3D 1
> =09dsw =3D (struct cdevsw *) 0xc0737f00
> #27 0xc054594b in dofilewrite (td=3D0xc3a5ad80, fp=3D0xc5874d38, fd=3D0, =
buf=3D0x0, nbyte=3D3228744800, offset=3DUnhandled dwarf expression opcode 0=
x93
> )
>     at file.h:246
> =09auio =3D {uio_iov =3D 0xee3e3c68, uio_iovcnt =3D 1, uio_offset =3D 150=
6491, uio_resid =3D 0,
>   uio_segflg =3D UIO_USERSPACE, uio_rw =3D UIO_WRITE, uio_td =3D 0xc3a5ad=
80}
> =09aiov =3D {iov_base =3D 0x80f30e5, iov_len =3D 0}
> =09cnt =3D 1
> =09error =3D -1066222496
> =09ktruio =3D (struct uio *) 0x0
> #28 0xc0545779 in write (td=3D0xc3a5ad80, uap=3D0xee3e3d04) at ../../../k=
ern/sys_generic.c:301
> =09fp =3D (struct file *) 0xc5874d38
> =09error =3D 0
> #29 0xc06bc280 in syscall (frame=3D
> ---Type <return> to continue, or q <return> to quit---
>       {tf_fs =3D 59, tf_es =3D 59, tf_ds =3D -1078001605, tf_edi =3D 0, t=
f_esi =3D 0, tf_ebp =3D -1077943160, tf_isp =3D -297910940, tf_ebx =3D 1352=
13056, tf_edx =3D 1, tf_ecx =3D 13, tf_eax =3D 4, tf_trapno =3D 0, tf_err =
=3D 2, tf_eip =3D 672630591, tf_cs =3D 51, tf_eflags =3D 514, tf_esp =3D -1=
077943188, tf_ss =3D 59})
>     at ../../../i386/i386/trap.c:951
> =09params =3D 0xbfbfe470 <Address 0xbfbfe470 out of bounds>
> =09callp =3D (struct sysent *) 0xc072ddc0
> =09td =3D (struct thread *) 0xc3a5ad80
> =09p =3D (struct proc *) 0xc3a593f8
> =09orig_tf_eflags =3D 514
> =09sticks =3D 61923
> =09error =3D 0
> =09narg =3D 3
> =09args =3D {13, 135213284, 1, 0, 0, -297910996, -1066739755, 135213056}
> =09code =3D 4
> #30 0xc06a688f in Xint0x80_syscall () at ../../../i386/i386/exception.s:2=
00
> No locals.
> #31 0x0000003b in ?? ()
> No symbol table info available.
> #32 0x0000003b in ?? ()
> No symbol table info available.
> #33 0xbfbf003b in ?? ()
> No symbol table info available.
> #34 0x00000000 in ?? ()
> No symbol table info available.
> #35 0x00000000 in ?? ()
> No symbol table info available.
> #36 0xbfbfe488 in ?? ()
> No symbol table info available.
> #37 0xee3e3d64 in ?? ()
> No symbol table info available.
> #38 0x080f3000 in ?? ()
> No symbol table info available.
> #39 0x00000001 in ?? ()
> ---Type <return> to continue, or q <return> to quit---
> No symbol table info available.
> #40 0x0000000d in ?? ()
> No symbol table info available.
> #41 0x00000004 in ?? ()
> No symbol table info available.
> #42 0x00000000 in ?? ()
> No symbol table info available.
> #43 0x00000002 in ?? ()
> No symbol table info available.
> #44 0x2817873f in ?? ()
> No symbol table info available.
> #45 0x00000033 in ?? ()
> No symbol table info available.
> #46 0x00000202 in ?? ()
> No symbol table info available.
> #47 0xbfbfe46c in ?? ()
> No symbol table info available.
> #48 0x0000003b in ?? ()
> No symbol table info available.
> #49 0x00000000 in ?? ()
> No symbol table info available.
> #50 0x00000000 in ?? ()
> No symbol table info available.
> #51 0x00000000 in ?? ()
> No symbol table info available.
> #52 0x00000000 in ?? ()
> No symbol table info available.
> #53 0x60abe000 in ?? ()
> No symbol table info available.
> #54 0xc3a593f8 in ?? ()
> No symbol table info available.
> #55 0xc3a5ad80 in ?? ()
> No symbol table info available.
> ---Type <return> to continue, or q <return> to quit---
> #56 0xee3e36d4 in ?? ()
> No symbol table info available.
> #57 0xee3e36b0 in ?? ()
> No symbol table info available.
> #58 0xc34df600 in ?? ()
> No symbol table info available.
> #59 0xc052d050 in sched_switch (td=3D0x0, newtd=3D0x80f3000, flags=3DCann=
ot access memory at address 0xbfbfe498
> ) at ../../../kern/sched_4bsd.c:971
> =09kg =3D (struct ksegrp *) 0x0
> =09p =3D (struct proc *) 0x0
> Previous frame inner to this frame (corrupt stack?)
>

--=20
Doug White                    |  FreeBSD: The Power to Serve
dwhite at gumbysoft.com          |  www.FreeBSD.org