Date: Fri, 17 Apr 1998 01:05:25 -0700 (PDT) From: "Jason K. Fritcher" <jkf@microline.org> To: FreeBSD-gnats-submit@FreeBSD.ORG Subject: misc/6329: _thread_flockfile hangs with NULL file pointer. Message-ID: <199804170805.BAA22860@sys1.microline.org>
next in thread | raw e-mail | index | archive | help
>Number: 6329
>Category: misc
>Synopsis: _thread_flockfile hangs with NULL file pointer.
>Confidential: no
>Severity: serious
>Priority: medium
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Fri Apr 17 01:10:14 PDT 1998
>Last-Modified:
>Originator: Jason K. Fritcher
>Organization:
N/A
>Release: FreeBSD 2.2.6-STABLE i386
>Environment:
FreeBSD sys1.microline.org 2.2.6-STABLE FreeBSD 2.2.6-STABLE #0: Sun Apr 5
14:20:20 PDT 1998 root@sys1.microline.org:/usr/src/sys/compile/microline i386
>Description:
Calling any function that calls _thread_flockfile with a file pointer that
happens to be NULL, the function will hang, and consume call idle cpu time.
>How-To-Repeat:
Save this to a file, ie blah.c.
#include <pthread.h>
#include <stdio.h>
main()
{
FILE* fBlah = NULL;
fprintf(fBlah, "Blah\n");
}
Then do this:
gcc -lc_r -o blah blah.c
./blah
hangs. Have to 'kill -9' to stop.
But this:
gcc -o blah blah.c
./blah
core dumps as expected.
>Fix:
Apply this patch to /usr/src/lib/libc_r/uthread/uthread_file.c
--- uthread_file.c.old Sun Jan 21 16:23:18 1996
+++ uthread_file.c Thu Apr 16 23:51:22 1998
@@ -42,10 +42,12 @@
int fd, flags;
int status;
- /* Block signals: */
- _thread_kern_sig_block(&status);
if ((fd = fileno(fp)) >= 0) {
+ /* Block signals: */
+ _thread_kern_sig_block(&status);
+
+
if (fp->_flags & __SRW) {
flags = FD_READ | FD_WRITE;
} else {
@@ -58,9 +60,10 @@
/* This might fail but POSIX doesn't give a damn. */
_thread_fd_lock(fd, flags, NULL, fname, lineno);
+
+ /* Unblock signals: */
+ _thread_kern_sig_unblock(status);
}
- /* Unblock signals: */
- _thread_kern_sig_unblock(status);
return;
}
>Audit-Trail:
>Unformatted:
To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-bugs" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199804170805.BAA22860>