Date: Fri, 23 Apr 1999 15:33:23 +0930 From: Greg Lehey <grog@lemis.com> To: FreeBSD current users <FreeBSD-current@FreeBSD.ORG> Subject: Problems with symbol sequences in recent kernels Message-ID: <19990423153323.P91260@freebie.lemis.com>
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I've just had a strange experience. I have some gdb macros which I
use for debugging Vinum. One, ps, gives me a ps-like listing:
(kgdb) ps
Check your .gdbinit, it contains a y command
pid proc addr uid ppid pgrp flag stat comm wchan
1544 c68a5100 c6df3000 0 1534 1544 004006 2 Vinum
1534 c68a57e0 c6ddb000 0 1524 1534 004086 3 bash wait c68a57e0
1524 c68a5c00 c6dc9000 1004 1516 1524 004086 3 bash wait c68a5c00
Another macro helps me load symbols from a kld:
Without:
(kgdb) bt
#0 Debugger (msg=0xc11696a0 "vinum debug") at ../../i386/i386/db_interface.c:318
#1 0xc1163585 in ?? ()
#2 0xc01826ea in spec_ioctl (ap=0xc6df4e1c) at ../../miscfs/specfs/spec_vnops.c:440
With:
(kgdb) bt
#0 Debugger (msg=0xc11696a0 "vinum debug") at ../../i386/i386/db_interface.c:318
#1 0xc1163585 in vinumioctl (dev=0x40001901, cmd=0xc008464b, data=0xc6df4ee0 "", flag=0x3, p=0xc68a5100)
at /src/PANIC/src/sys/modules/Vinum/../../dev/Vinum/vinumioctl.c:96
#2 0xc01826ea in spec_ioctl (ap=0xc6df4e1c) at ../../miscfs/specfs/spec_vnops.c:440
This has worked quite nicely for some time. Since yesterday, after
building a kernel with newbus support, I get strange messages if I
read in the Vinum symbols before reading in the kernel symbols:
(kgdb) bt
#0 Debugger (msg=0xc11696a0 "vinum debug") at ../../i386/i386/db_interface.c:318
#1 0xc1163585 in vinumioctl (dev=0x40001901, cmd=0xc008464b, data=0xc6df4ee0 "", flag=0x3, p=0xc68a5100)
at /src/PANIC/src/sys/modules/Vinum/../../dev/Vinum/vinumioctl.c:96
During symbol reading, "repeated" header file opt_global.h not previously seen, at symtab pos 23.
During symbol reading, Invalid symbol data: type number (2,2) out of range at symtab pos 25..
#2 0xc01826ea in spec_ioctl (ap=0xc6df4e1c) at ../../miscfs/specfs/spec_vnops.c:440
The following stack frames also look strange:
#5 0xc017ccdd in vn_ioctl (fp=<error type>, com=<incomplete type>, data=<incomplete type>, p=<error type>)
at vnode_if.h:395
#6 0xc015c5f7 in ioctl (p=0xc68a5100, uap=0xc6df4f94) at ../../kern/sys_generic.c:564
#7 0xc021e916 in syscall (frame=<error type>) at ../../i386/i386/trap.c:1071
I debugged gdb and found that it was finding these references
(opt_global.h) in cd9660_rrip.o, which it read after reading the Vinum
kld symbols. If I can convince it to read the kernel symbols first, I
don't have any trouble. I don't think that it's anything to do with
that particular file; there must be about 30 files in a typical kernel
build which refer to this symbol.
If I don't get any response on the list, I'll put in a PR, but I
thought there's a good chance that somebody will recognize this
problem and be able to fix it.
Greg
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