Date: Fri, 13 Jun 1997 13:56:40 -0700 From: "Jin Guojun[ITG]" <jin@george.lbl.gov> To: smp@csn.net Cc: bugs@FreeBSD.ORG, smp@FreeBSD.ORG Subject: Re: (kern/3827) : was ASUS P/I-P65UP5 with C-P55T2D Message-ID: <199706132056.NAA22863@george.lbl.gov>
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The problem has been narrowed to a very small program at below.
It appears to happen at subroutine level. That is, the open/freopn works
in main() program, but fails in subroutine. To replace the subroutine call
at line 7 in main(), marked /* replace HERE */, with the body of openread() ,
then, program works. So, what can cause this problem?
----------------------------------------------
/* openread.c */
#include <stdio.h>
main(int argc, char **argv)
{
openread(argc > 1 ? argv[1] : "openread.c"); /* replace HERE */
}
openread(char *fn) /* if put body below into main, then it works */
{
FILE * fp = stdin;
int c;
if (!(fp=fopen(fn, "rb")))
exit(1);
while( (c = fgetc(fp)) != EOF)
fputc(c, stdout);
if (!(fp=freopen(fn, "rb", stdin)))
exit(2);
while (fread(&c, sizeof(c), 1, fp) == 1)
fwrite(&c, sizeof(c), 1, stdout);
fclose(fp);
}
------------------------------------------------
to load:
cc -g openread.c -lc_r
------------------------------------------------
xxgdb can't trace this program, but gdb can.
It hangs at _thread_sys_sigprocmask() call.
Because I am not fimilar with thread_sys_calls(),
would some one help me on solving it?
Any information, hints, and comments are appreciated.
thanks,
-Jin
=======================================
Below is the gdb tracing:
gdb a.out
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under certain conditions; type "show copying" to see the conditions.
There is absolutely no warranty for GDB; type "show warranty" for details.
GDB 4.16 (i386-unknown-freebsd),
Copyright 1996 Free Software Foundation, Inc...
(gdb) l
1 /* openread.c */
2
3 #include <stdio.h>
4
5 main(int argc, char **argv)
6 {
7 openread(argc > 1 ? argv[1] : "openread.c");
8 }
9
10 openread(char *fn)
(gdb) b 7
Breakpoint 1 at 0x1594: file openread.c, line 7.
(gdb) run
Starting program: /export/src/ccs-lib/tools/x11/tuner/FreeBSD/a.out
Breakpoint 1, main (argc=1, argv=0xefbfda5c) at openread.c:7
7 openread(argc > 1 ? argv[1] : "openread.c");
(gdb) s
openread (fn=0x1580 "openread.c") at openread.c:12
12 FILE * fp = stdin;
(gdb) s
15 if (!(fp=fopen(fn, "rb")))
(gdb) s
fopen (file=0x1580 "openread.c", mode=0x15b4 "rb")
at /usr/src/lib/libc_r/../libc/stdio/fopen.c:57
57 if ((flags = __sflags(mode, &oflags)) == 0)
(gdb) s
__sflags (mode=0x15b4 "rb", optr=0xefbfda0c)
at /usr/src/lib/libc_r/../libc/stdio/flags.c:63
63 switch (*mode++) {
(gdb) s
66 ret = __SRD;
(gdb) s
67 m = O_RDONLY;
(gdb) s
68 o = 0;
(gdb) s
69 break;
(gdb) s
89 if (*mode == '+' || (*mode == 'b' && mode[1] == '+')) {
(gdb) s
93 *optr = m | o;
(gdb) s
95 }
(gdb) s
fopen (file=0x1580 "openread.c", mode=0x15b4 "rb")
at /usr/src/lib/libc_r/../libc/stdio/fopen.c:59
59 if ((fp = __sfp()) == NULL)
(gdb) s
__sfp () at /usr/src/lib/libc_r/../libc/stdio/findfp.c:105
105 if (!__sdidinit)
(gdb) s
106 __sinit();
(gdb) s
__sinit () at /usr/src/lib/libc_r/../libc/stdio/findfp.c:173
173 __cleanup = _cleanup; /* conservative */
(gdb) s
174 __sdidinit = 1;
(gdb) s
175 }
(gdb) s
__sfp () at /usr/src/lib/libc_r/../libc/stdio/findfp.c:107
107 for (g = &__sglue;; g = g->next) {
(gdb) s
108 for (fp = g->iobs, n = g->niobs; --n >= 0; fp++)
(gdb) s
109 if (fp->_flags == 0)
(gdb) s
108 for (fp = g->iobs, n = g->niobs; --n >= 0; fp++)
(gdb) s
109 if (fp->_flags == 0)
(gdb) s
108 for (fp = g->iobs, n = g->niobs; --n >= 0; fp++)
(gdb) s
109 if (fp->_flags == 0)
(gdb) s
108 for (fp = g->iobs, n = g->niobs; --n >= 0; fp++)
(gdb) s
111 if (g->next == NULL && (g->next = moreglue(NDYNAMIC)) == NULL)
(gdb) s
107 for (g = &__sglue;; g = g->next) {
(gdb) s
108 for (fp = g->iobs, n = g->niobs; --n >= 0; fp++)
(gdb) s
109 if (fp->_flags == 0)
(gdb) s
116 fp->_flags = 1; /* reserve this slot; caller sets real flags */
(gdb) s
117 fp->_p = NULL; /* no current pointer */
(gdb) s
118 fp->_w = 0; /* nothing to read or write */
(gdb) s
119 fp->_r = 0;
(gdb) s
120 fp->_bf._base = NULL; /* no buffer */
(gdb) s
121 fp->_bf._size = 0;
(gdb) s
122 fp->_lbfsize = 0; /* not line buffered */
(gdb) s
123 fp->_file = -1; /* no file */
(gdb) s
125 fp->_ub._base = NULL; /* no ungetc buffer */
(gdb) s
126 fp->_ub._size = 0;
(gdb) s
127 fp->_lb._base = NULL; /* no line buffer */
(gdb) s
128 fp->_lb._size = 0;
(gdb) s
130 }
(gdb) s
fopen (file=0x1580 "openread.c", mode=0x15b4 "rb")
at /usr/src/lib/libc_r/../libc/stdio/fopen.c:61
61 if ((f = open(file, oflags, DEFFILEMODE)) < 0) {
(gdb) s
open (path=0x1580 "openread.c", flags=0)
at /usr/src/lib/libc_r/uthread/uthread_open.c:45
45 int mode = 0;
(gdb) s
50 _thread_kern_sig_block(&status);
(gdb) s
_thread_kern_sig_block (status=0xefbfd9ec)
at /usr/src/lib/libc_r/uthread/uthread_kern.c:952
952 _thread_sys_sigprocmask(SIG_SETMASK, &sig_to_block, &oset);
(gdb) s
Hanging HERE !!!
help
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