[microblaze-uclinux] BUG: fstat64() clobbers stack; uclibc and kernel don't agree on "struct kernel_stat64".

[Graeme Smecher <graeme.smecher@xxxxxxxxxxxxxx>]

Hi,

I've just tracked down a header mismatch that causes stack corruption on 
Petalinux releases v0.20-rc3 and v0.30-rc1. The fstat64() syscall relies 
on coherent headers between the kernel and userspace, but they appear to 
be out-of-sync. We have:

-----------

$  diff -ub linux-2.4.x/include/asm-microblaze/stat.h 
uClibc/libc/sysdeps/linux/microblaze/bits/kernel_stat.h
--- linux-2.4.x/include/asm-microblaze/stat.h    2006-01-30 
00:57:53.000000000 -0500
+++ uClibc/libc/sysdeps/linux/microblaze/bits/kernel_stat.h    
2006-01-29 22:37:04.000000000 -0500
@@ -1,7 +1,10 @@
-#ifndef __MICROBLAZE_STAT_H__
-#define __MICROBLAZE_STAT_H__
+/* Stat structure for linux/microblaze*/

-struct stat {
+#ifndef _BITS_STAT_STRUCT_H
+#define _BITS_STAT_STRUCT_H
+
+struct kernel_stat
+{
    __kernel_dev_t    st_dev;
    __kernel_ino_t    st_ino;
    __kernel_mode_t    st_mode;
@@ -22,7 +25,8 @@
    unsigned long    __unused5;
};

-struct stat64 {
+struct kernel_stat64
+{
    __kernel_dev_t    st_dev;
    unsigned long    __unused0;
    unsigned long    __unused1;
@@ -42,8 +46,8 @@
    __kernel_loff_t    st_size;
    unsigned long    st_blksize;

-    unsigned long    st_blocks; /* No. of 512-byte blocks allocated */
    unsigned long    __unused4; /* future possible st_blocks high bits */
+    unsigned long    st_blocks;    /* Number 512-byte blocks allocated. */

    unsigned long    st_atime;
    unsigned long    __unused5;
@@ -53,8 +57,6 @@

    unsigned long    st_ctime;
    unsigned long    __unused7; /* high 32 bits of ctime someday */
-
-    unsigned long    __unused8;
};

-#endif /* __MICROBLAZE_STAT_H__ */
+#endif    /*  _BITS_STAT_STRUCT_H */

-----------

Two problems:
  * the kernel_stat->st_blocks entry is in the wrong spot, and
  * __unused8 is present in the kernel, but not in userspace. The 
result is a clobbered int32_t on the stack.

Please let me know if I can do anything to help resolve this.

regards,
Graeme Smecher
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