runtime: fix mmap error return on linux.

Fixes #1511 again.

R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/4527070

diff --git a/src/pkg/runtime/linux/mem.c b/src/pkg/runtime/linux/mem.c
index ce1a8aa70b26582d425ef35f51dac0ad5d709485..02f798732fed60c4a6fbf920b0b47e6feb54fe9c 100644 (file)
--- a/src/pkg/runtime/linux/mem.c
+++ b/src/pkg/runtime/linux/mem.c
@@ -39,13 +39,19 @@ runtime·SysFree(void *v, uintptr n)
 void*
 runtime·SysReserve(void *v, uintptr n)
 {
+       void *p;
+
        // On 64-bit, people with ulimit -v set complain if we reserve too
        // much address space.  Instead, assume that the reservation is okay
        // and check the assumption in SysMap.
        if(sizeof(void*) == 8)
                return v;
        
-       return runtime·mmap(v, n, PROT_NONE, MAP_ANON|MAP_PRIVATE, -1, 0);
+       p = runtime·mmap(v, n, PROT_NONE, MAP_ANON|MAP_PRIVATE, -1, 0);
+       if(p < (void*)4096) {
+               return nil;
+       }
+       return p;
 }
 
 enum
@@ -63,6 +69,8 @@ runtime·SysMap(void *v, uintptr n)
        // On 64-bit, we don't actually have v reserved, so tread carefully.
        if(sizeof(void*) == 8) {
                p = runtime·mmap(v, n, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_ANON|MAP_PRIVATE, -1, 0);
+               if(p == (void*)ENOMEM)
+                       runtime·throw("runtime: out of memory");
                if(p != v) {
                        runtime·printf("runtime: address space conflict: map(%p) = %p\n", v, p);
                        runtime·throw("runtime: address space conflict");
@@ -71,7 +79,7 @@ runtime·SysMap(void *v, uintptr n)
        }
 
        p = runtime·mmap(v, n, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_ANON|MAP_FIXED|MAP_PRIVATE, -1, 0);
-       if(p == (void*)-ENOMEM)
+       if(p == (void*)ENOMEM)
                runtime·throw("runtime: out of memory");
        if(p != v)
                runtime·throw("runtime: cannot map pages in arena address space");