runtime: mmap(2) on Solaris & Illumos can return EAGAIN.

In low memory situations mmap(2) on Illumos[2] can return EAGAIN when it is unable to reserve the necessary space for the requested mapping. Go was not previously handling this correctly for Illumos and would fail to recognize it was in a low-memory situation, the result being the program would terminate with a panic instead of running the GC. Fixes: #14930 [1]: https://www.illumos.org/man/2/mmap Change-Id: I889cc0547e23f9d6c56e4fdd7bcbd0e15403873a Reviewed-on: https://go-review.googlesource.com/43461 Reviewed-by: Brad Fitzpatrick <[email protected]>
golang · May 16, 2017 · 13cdd81 · 13cdd81
1 parent 3b263e4
commit 13cdd81
Showing 1 changed file with 3 additions and 2 deletions.
diff --git a/src/runtime/mem_bsd.go b/src/runtime/mem_bsd.go
@@ -59,6 +59,7 @@ func sysReserve(v unsafe.Pointer, n uintptr, reserved *bool) unsafe.Pointer {
 	return p
 }
 
+const _sunosEAGAIN = 11
 const _ENOMEM = 12
 
 func sysMap(v unsafe.Pointer, n uintptr, reserved bool, sysStat *uint64) {
@@ -76,7 +77,7 @@ func sysMap(v unsafe.Pointer, n uintptr, reserved bool, sysStat *uint64) {
 			flags |= _MAP_FIXED
 		}
 		p := mmap(v, n, _PROT_READ|_PROT_WRITE, flags, -1, 0)
-		if uintptr(p) == _ENOMEM {
+		if uintptr(p) == _ENOMEM || (GOOS == "solaris" && uintptr(p) == _sunosEAGAIN) {
 			throw("runtime: out of memory")
 		}
 		if p != v {
@@ -87,7 +88,7 @@ func sysMap(v unsafe.Pointer, n uintptr, reserved bool, sysStat *uint64) {
 	}
 
 	p := mmap(v, n, _PROT_READ|_PROT_WRITE, _MAP_ANON|_MAP_FIXED|_MAP_PRIVATE, -1, 0)
-	if uintptr(p) == _ENOMEM {
+	if uintptr(p) == _ENOMEM || (GOOS == "solaris" && uintptr(p) == _sunosEAGAIN) {
 		throw("runtime: out of memory")
 	}
 	if p != v {