Hi!
On Wed, 2016-11-09 at 23:46:42 +0000, James Clarke wrote:
> Package: dpkg-dev
> Version: 1.18.13
> Severity: important
> User: [email protected]
> Usertags: sparc64
> X-Debbugs-Cc: [email protected]
> Unfortunately, your new specs files lead to segfaults on sparc64:
>
> > $ cat exit.c
> > #include <stdlib.h>
> >
> > int main(int argc, char **argv) {
> > exit(1);
> > return 2;
> > }
> > $ gcc -specs=/usr/share/dpkg/pie-compile.specs -c exit.c -o exit.o
> > $ gcc -specs=/usr/share/dpkg/pie-link.specs exit.o -o exit
> > $ ./exit
> > Segmentation fault
>
> This is because, while cc1 is given -fPIE, as is not given anything. For
> most architectures, this is actually fine, but on SPARC, as *must* be
> given -K PIC. When looking at strace, this is the only difference
> between gcc -specs=... and gcc -fPIE for compiling. Otherwise, what
> happens is the assembler does not emit a PLT call, instead leaving the
> call address as an immediate to be filled in by a 30-bit relocation,
> which doesn't fit at runtime (with this particular example, libc was
> loaded such that exit was at 0xfff80001001624e0) and gets truncated.
> Note that the linker invocation itself is fine; it was just given bad
> input (although perhaps this is something it could have caught and given
> an error message?).
>
> As far as I can tell, changing the cc1_options to self_spec in
> (no-)pie-compile.specs should work fine. It certainly fixes the problem
> here, and off the top of my head, I can't think of any issues this would
> cause.
Thanks for the analysis! I've done several changes to the specs, I've
tried on a powerpc schroot I had already lying around due to another
report, if you could test on sparc64 that would be appreciated!
Attached the changes.
Thanks,
Guillem
diff --git i/data/no-pie-compile.specs w/data/no-pie-compile.specs
index f85b394..2277b97 100644
--- i/data/no-pie-compile.specs
+++ w/data/no-pie-compile.specs
@@ -1,2 +1,2 @@
-*cc1_options:
+*self_spec:
+ %{!r:%{!fpie:%{!fPIE:%{!fpic:%{!fPIC:%{!fno-pic:-fno-PIE}}}}}}
diff --git i/data/no-pie-link.specs w/data/no-pie-link.specs
index 15243a0..54db649 100644
--- i/data/no-pie-link.specs
+++ w/data/no-pie-link.specs
@@ -1,2 +1,2 @@
*self_spec:
-+ %{!shared:%{!r:-fno-PIE -no-pie}}
++ %{!shared:%{!r:%{!fPIE:%{!pie:-fno-PIE -no-pie}}}}
diff --git i/data/pie-compile.specs w/data/pie-compile.specs
index fc54bcb..74d8215 100644
--- i/data/pie-compile.specs
+++ w/data/pie-compile.specs
@@ -1,2 +1,2 @@
-*cc1_options:
-+ %{!r:%{!fpie:%{!fPIE:%{!fpic:%{!fPIC:%{!fno-pic:-fPIE}}}}}}
+*self_spec:
++ %{!r:%{!fpie:%{!fPIE:%{!fpic:%{!fPIC:%{!fno-pic:%{!fno-PIE:%{!no-pie:-fPIE}}}}}}}}
diff --git i/data/pie-link.specs w/data/pie-link.specs
index a5e0fe4..35d26e1 100644
--- i/data/pie-link.specs
+++ w/data/pie-link.specs
@@ -1,2 +1,2 @@
*self_spec:
-+ %{!shared:%{!r:-fPIE -pie}}
++ %{!shared:%{!r:%{!fno-PIE:%{!no-pie:-fPIE -pie}}}}
