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authorEfraim Flashner <efraim@flashner.co.il>2017-02-14 21:48:30 +0200
committerEfraim Flashner <efraim@flashner.co.il>2017-02-20 12:58:06 +0200
commit77e16733197b8950f6b665be1f69375cb2a7155f (patch)
treee939354807138560f721b5d5090f10604fd97c98 /nix
parent653add37af10b0d5dbc20c8bc7ce30eec8cf4ae7 (diff)
downloadguix-77e16733197b8950f6b665be1f69375cb2a7155f.tar.gz
daemon: Ensure proper alignment on the stack.
* nix/libstore/build.cc (startBuilder): When calling 'clone', increase
the step to 16 and ensure it aligns properly on the stack.
Diffstat (limited to 'nix')
-rw-r--r--nix/libstore/build.cc7
1 files changed, 6 insertions, 1 deletions
diff --git a/nix/libstore/build.cc b/nix/libstore/build.cc
index cebc404d1c..9b7bb5391c 100644
--- a/nix/libstore/build.cc
+++ b/nix/libstore/build.cc
@@ -26,6 +26,7 @@
 #include <errno.h>
 #include <stdio.h>
 #include <cstring>
+#include <stdint.h>
 
 #include <pwd.h>
 #include <grp.h>
@@ -2008,7 +2009,11 @@ void DerivationGoal::startBuilder()
 	char stack[32 * 1024];
 	int flags = CLONE_NEWPID | CLONE_NEWNS | CLONE_NEWIPC | CLONE_NEWUTS | SIGCHLD;
 	if (!fixedOutput) flags |= CLONE_NEWNET;
-	pid = clone(childEntry, stack + sizeof(stack) - 8, flags, this);
+
+	/* Ensure proper alignment on the stack.  On aarch64, it has to be 16
+	   bytes.  */
+	pid = clone(childEntry, (char *)(((uintptr_t)stack + 16) & ~0xf),
+		    flags, this);
 	if (pid == -1)
 	    throw SysError("cloning builder process");
     } else