mknod() broken with uclibc built with -O0

[Tino Keitel]

Hi,

the mknod() syscall is broken in my ulibc if I compile with -O0. I
discoverd this with uclibc 0.9.29 (not sure if 0.9.28 was also
affected) and gcc 4.1, and it still applies to the current git of
buildroot using uclibc 0.9.30 and gcc 4.3.2. The i386 architecture was
used.

For the test, I use the following command. The busybox is the one from
buildroot, and is therefore statically linked against the uclibc from
buildroot.

$ strace ./bin/busybox mknod foobar c 10 63

With -O0, strace looks like this:

mknod("foobar", S_IFCHR|037746400666, makedev(2314, 104767)) = -1

2314 translates to 0x90a , to this is the 10, prefixed with some
trash. 104767 translates to 1993f, so this is the 63, prefixed with
some trash. I think the same applies to the mode.

This is the raw strace output, gathered with strace -e raw=mknod:

mknod(0xffa31a31, 0xffa321b6, 0x19990a3f) = -1

With DODEBUG disabled in the uclibc config, and therefore compiled with
-O2, strace looks like this:

mknod("foobar", S_IFCHR|0666, makedev(10, 63)) = -1

So it looks like there is some mangling of the mknod() arguments in
uclibc, which breaks if compiled with -O0.

Regards,
Tino

-- 
Tino Keitel
Software Engineer
 
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