Re: Bug#816077: ruby2.3: FTBFS on m68k - Segmentation fault at 0x5f583332

[John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>]

Hi!

Here's an updated patch which contains the actual changes that upstream
committed to the git repository to close the upstream bug 12118 [1].

Would be possible to cherry-pick this fix from upstream until the
changes have been backported to ruby2.3? I'd be happy to perform
an NMU as well to fix the issue. I assume that should be okay since
ruby2,3 is LowNMU?

Attaching the updated and cleaned up patch in any case.

Adrian

> [1] https://bugs.ruby-lang.org/issues/12118

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer - glaubitz@debian.org
`. `'   Freie Universitaet Berlin - glaubitz@physik.fu-berlin.de
  `-    GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913

Description: Cherry-picked updates for upstream bug 12118
 Upstream has improved the stack allocator and fixed the function
 prototype for rb_locale_charmap_index in localeinit.c. Both changes
 are necessary to fix the build on m68k.
 Upstream bug: https://bugs.ruby-lang.org/issues/12118
 Debian bug: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=816077
 .

--- ruby2.3-2.3.0.orig/localeinit.c
+++ ruby2.3-2.3.0/localeinit.c
@@ -89,7 +89,7 @@ enc_find_index(const char *name)
 }
 
 int
-rb_locale_charmap_index(VALUE klass)
+rb_locale_charmap_index(void)
 {
     return (int)locale_charmap(enc_find_index);
 }
--- ruby2.3-2.3.0.orig/thread_pthread.c
+++ ruby2.3-2.3.0/thread_pthread.c
@@ -690,17 +690,31 @@ reserve_stack(volatile char *limit, size
 	const volatile char *end = buf + sizeof(buf);
 	limit += size;
 	if (limit > end) {
-	    size = limit - end;
-	    limit = alloca(size);
-	    limit[stack_check_margin+size-1] = 0;
+           /* |<-bottom (=limit(a))                                     top->|
+            * | .. |<-buf 256B |<-end                          | stack check |
+            * |  256B  |              =size=                   | margin (4KB)|
+            * |              =size=         limit(b)->|  256B  |             |
+            * |                |       alloca(sz)     |        |             |
+            * | .. |<-buf      |<-limit(c)    [sz-1]->0>       |             |
+            */
+           size_t sz = limit - end;
+           limit = alloca(sz);
+           limit[sz-1] = 0;
 	}
     }
     else {
 	limit -= size;
 	if (buf > limit) {
-	    limit = alloca(buf - limit);
-	    limit[0] = 0; /* ensure alloca is called */
-	    limit -= stack_check_margin;
+           /* |<-top (=limit(a))                                     bottom->|
+            * | .. | 256B buf->|                               | stack check |
+            * |  256B  |              =size=                   | margin (4KB)|
+            * |              =size=         limit(b)->|  256B  |             |
+            * |                |       alloca(sz)     |        |             |
+            * | .. |      buf->|           limit(c)-><0>       |             |
+            */
+           size_t sz = buf - limit;
+           limit = alloca(sz);
+           limit[0] = 0;
 	}
     }
 }