Date: 17 Jun 2000 17:41:29 -0000 From: greg@straynet.com To: FreeBSD-gnats-submit@freebsd.org Subject: bin/19355: fstat gives signal 10 (SIGBUS) when outputting data Message-ID: <20000617174129.84754.qmail@straynet.com>
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>Number: 19355
>Category: bin
>Synopsis: fstat gives signal 10 (SIGBUS) when outputting data
>Confidential: no
>Severity: non-critical
>Priority: medium
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Sat Jun 17 10:50:00 PDT 2000
>Closed-Date:
>Last-Modified:
>Originator: Greg Prosser
>Release: FreeBSD 3.4-STABLE i386
>Organization:
Straynet Online
>Environment:
Straynet is a public hosting machine, with many users. When executing
a script which calls sockstat I noticed fstat was dying on SIGBUS
repeatedly. I changed CFLAGS in the /usr/src Makefile for fstat to include
-g, and ran it through gdb and still could not find the problem.
The sources are the ones currently in the RELENG_3 line (I used anoncvs to
checkout the sources, and ran diffs. No changes) and are running on a
FreeBSD-stable machine with the following uname tag:
FreeBSD voyager.straynet.com 3.4-STABLE FreeBSD 3.4-STABLE #0: Tue May 16 \
20:16:55 EDT 2000 gregp@voyager.straynet.com:/usr/src/sys/compile/USERSSUCK \
i386
(Long lines wrapped with \)
>Description:
This problem popped up when I was running sockstat, as stated earlier, and was
then isolated to fstat specifically. It appeared to core when listing information
for a specific user (it was the last user in the list that appeared onscreen when
doing a plain 'fstat' before it SIGBUS'd), and the behaviour repeats when I use
fstat -u username. Example follows with gdb output.
[root@voyager] /usr/src/usr.bin/fstat: make clean all
[root@voyager] /usr/src/usr.bin/fstat: cd /usr/obj/usr/src/usr.bin/fstat
[root@voyager] /usr/obj/usr/src/usr.bin/fstat: gdb ./fstat
GNU gdb 4.18
Copyright 1998 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 "i386-unknown-freebsd"...
(gdb) run -u bin2ooo
Starting program: /usr/obj/usr/src/usr.bin/fstat/./fstat -u bin2ooo
USER CMD PID FD MOUNT INUM MODE SZ|DV R/W
bin2ooo bnc 10558 root / 2 drwxr-xr-x 1024 r
bin2ooo bnc 10558 wd /home 1714378 drwxr-xr-x 512 r
bin2ooo bnc 10558 text /usr 3190287 -rwxr-xr-x 79658 r
bin2ooo bnc 10558 0 / 6766 crw--w---- ttyp2 rw
bin2ooo bnc 10558 1 / 6766 crw--w---- ttyp2 rw
bin2ooo bnc 10558 2 / 6766 crw--w---- ttyp2 rw
bin2ooo bnc 10558 3* internet stream tcp dc5b9180
bin2ooo bnc 10558 4 /home 1714190 -rw-r--r-- 25717 w
bin2ooo bnc 10558 6* internet stream tcp dc5d4840
bin2ooo bnc 10558 7* internet stream tcp dc5ff2a0
bin2ooo bash 10547 text /usr 3190357 -rwxr-xr-x 367780 r
Program received signal SIGBUS, Bus error.
0x280cd832 in bcopy () from /usr/lib/libc.so.3
(gdb) bt
#0 0x280cd832 in bcopy () from /usr/lib/libc.so.3
#1 0x5 in ?? ()
#2 0x8048e80 in main (argc=3, argv=0xbfbfdbe8)
at /usr/src/usr.bin/fstat/fstat.c:265
#3 0x80489f5 in _start ()
(gdb) up
#1 0x5 in ?? ()
(gdb) up
#2 0x8048e80 in main (argc=3, argv=0xbfbfdbe8)
at /usr/src/usr.bin/fstat/fstat.c:265
265 dofiles(p);
(gdb) list
260 putchar('\n');
261
262 for (plast = &p[cnt]; p < plast; ++p) {
263 if (p->kp_proc.p_stat == SZOMB)
264 continue;
265 dofiles(p);
266 }
267 exit(0);
268 }
269
(gdb) quit
The program is running. Exit anyway? (y or n) y
[root@voyager] /usr/obj/usr/src/usr.bin/fstat: ps uwxU bin2ooo
USER PID %CPU %MEM VSZ RSS TT STAT STARTED TIME COMMAND
bin2ooo 10547 0.0 0.0 0 0 p2 IEs+ - 0:00.00 (bash)
bin2ooo 10558 0.0 0.1 1000 576 ?? Is Thu08PM 0:03.63 bnc
[root@voyager] /usr/obj/usr/src/usr.bin/fstat:
>How-To-Repeat:
I'm not sure if this can be reproduced on other systems, I can't
seem to track down this error myself, so I can't pinpoint where it's
failing and thus reproduce it elsewhere, but for the last ten minutes
the same action has caused this to happen again and again. More info
available upon request (that's if it's still
failing when you request it :))
>Fix:
I'm wondering if this is a memory failure somewhere in fstat? I'm
no FreeBSD hacker, so I don't have the slightest clue.
>Release-Note:
>Audit-Trail:
>Unformatted:
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