Bug#200619: gcc: parisc: compiling dietlibc-dev with -Os causes segfault

[Gerrit Pape <pape-dbnbgs@smarden.org>]

Package: gcc

This applies to gcc_3.2.3-6 and gcc_3.3.1-0pre0 on hppa; gcc_3.0.4-16
doesn't have this problem.

The dietlibc_0.22-2 builds with -Os by default on hppa, and this test
program linked against the dietlibc dies with a segfault after fopen():

#include <stdio.h>
int main() {
  FILE *f;
  fopen("foo", "a");
  fclose(f);
  return(0);
}

If the dietlibc is built without -Os, the program works fine.

The bug is triggered by the following changes in
dietlibc/libstdio/fdglue2.c (I attach fdglue2.c for reference):

diff -u -r1.10 -r1.11
--- libstdio/fdglue2.c  9 Feb 2002 00:45:18 -0000       1.10
+++ libstdio/fdglue2.c  4 Dec 2002 18:32:33 -0000       1.11
@@ -1,5 +1,6 @@
 #include <unistd.h>
 #include <fcntl.h>
+#include <sys/stat.h>
 #include <errno.h>
 #include "dietstdio.h"
 #include <stdlib.h>
@@ -23,7 +24,12 @@
   tmp->bm=0;
   tmp->bs=0;
   tmp->buflen=BUFSIZE;
-  tmp->flags=0;
+  {
+    struct stat st;
+    fstat(fd,&st);
+    tmp->flags=(S_ISFIFO(st.st_mode))?FDPIPE:0;
+  }
+  tmp->popen_kludge=0;
   if (__stdio_atexit==0) {
     __stdio_atexit=1;
     atexit(__stdio_flushall);
  
The dietlibc compiled with revision 1.10 doesn't segfault, revision 1.11
does.

The code changes look fine to me, and it works on other architectures,
so I suppose it's a problem with gcc version >=3.2 on hppa optimizing
the code.

I've a complete test environment on paer, and did run this through gdb
several times.  If you need more details, just ask for it, I should be
able to provide them.

Regards, Gerrit.

#include <unistd.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <errno.h>
#include "dietstdio.h"
#include <stdlib.h>
#include <pthread.h>

extern int __stdio_atexit;

FILE* __stdio_init_file_nothreads(int fd,int closeonerror);
FILE* __stdio_init_file_nothreads(int fd,int closeonerror) {
  FILE *tmp=(FILE*)malloc(sizeof(FILE));
  if (!tmp) goto err_out;
  tmp->buf=(char*)malloc(BUFSIZE);
  if (!tmp->buf) {
    free(tmp);
err_out:
    if (closeonerror) close(fd);
    errno=ENOMEM;
    return 0;
  }
  tmp->fd=fd;
  tmp->bm=0;
  tmp->bs=0;
  tmp->buflen=BUFSIZE;
  {
    struct stat st;
    fstat(fd,&st);
    tmp->flags=(S_ISFIFO(st.st_mode))?FDPIPE:0;
  }
  tmp->popen_kludge=0;
  if (__stdio_atexit==0) {
    __stdio_atexit=1;
    atexit(__stdio_flushall);
  }
  tmp->next=__stdio_root;
  __stdio_root=tmp;
  tmp->ungotten=0;
  return tmp;
}

FILE* __stdio_init_file(int fd,int closeonerror) __attribute__((weak,alias("__stdio_init_file_nothreads")));