On 2016-08-08, at 5:50 AM, Aurelien Jarno wrote:
> Looking more in details, there are small differences in the two
> implementations, but the only one that changes the behaviour is due to
> this missing hunk in the upstream version:
>
> --- a/nptl/allocatestack.c
> +++ b/nptl/allocatestack.c
> @@ -683,9 +692,13 @@
> prot) != 0)
> goto mprot_error;
> #elif _STACK_GROWS_UP
> - if (mprotect ((char *) pd - pd->guardsize,
> - pd->guardsize - guardsize, prot) != 0)
> - goto mprot_error;
> + char *new_guard = (char *) (((uintptr_t) pd - guardsize) &
> ~pagesize_m1);
> + char *old_guard = (char *) (((uintptr_t) pd - pd->guardsize) &
> ~pagesize_m1);
> + /* The guard size difference might be > 0, but once rounded
> + to the nearest page the size difference might be zero. */
> + if (old_guard - new_guard > 0)
> + if (mprotect (old_guard, new_guard - old_guard, prot) != 0)
> + goto mprot_error;
> #endif
>
> pd->guardsize = guardsize;
>
> It therefore looks like this should also be upstreamed. We can add it
> back in the debian version in the meantime.
Thanks for comparing patches.
I tried to confirm the above change fixes the test regression using upstream
source but it seems binutils 2.27-2 is broken:
[...]
a - elf/dl-tsd.os
hppa-linux-gnu-gcc-6 -nostdlib -nostartfiles -r -o
/home/dave/gnu/glibc/objdir/elf/librtld.map.o '-Wl,-('
/home/dave/gnu/glibc/objdir/elf/dl-allobjs.os
/home/dave/gnu/glibc/objdir/libc_pic.a -lgcc '-Wl,-)'
-Wl,-Map,/home/dave/gnu/glibc/objdir/elf/librtld.mapT
/usr/bin/ld:/home/dave/gnu/glibc/objdir/libc_pic.a: file format not recognized;
treating as linker script
/usr/bin/ld:/home/dave/gnu/glibc/objdir/libc_pic.a:1: syntax error
collect2: error: ld returned 1 exit status
Makefile:349: recipe for target '/home/dave/gnu/glibc/objdir/elf/librtld.map'
failed
make[2]: *** [/home/dave/gnu/glibc/objdir/elf/librtld.map] Error 1
The error doesn't occur with 2.26.1.
Dave
--
John David Anglin dave.ang...@bell.net
