From a1aa5dabaa5d570710da7190a3c3dca5442b9daa Mon Sep 17 00:00:00 2001 From: Mark H Weaver Date: Mon, 7 Aug 2017 16:41:03 -0400 Subject: daemon: Ensure the child stack is aligned on a 16-byte boundary. * nix/libstore/build.cc (DerivationGoal::startBuilder): When calling 'clone', ensure that the stack is aligned on a 16-byte boundary. --- nix/libstore/build.cc | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/nix/libstore/build.cc b/nix/libstore/build.cc index 693fa70c8d..63540ddfc1 100644 --- a/nix/libstore/build.cc +++ b/nix/libstore/build.cc @@ -26,6 +26,7 @@ #include #include #include +#include #include #include @@ -2008,11 +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; -#ifdef __aarch64__ - pid = clone(childEntry, stack + sizeof(stack) - 16, flags, this); -#else - pid = clone(childEntry, stack + sizeof(stack) - 8, flags, this); -#endif + /* Ensure proper alignment on the stack. On aarch64, it has to be 16 + bytes. */ + pid = clone(childEntry, + (char *)(((uintptr_t)stack + sizeof(stack) - 8) & ~(uintptr_t)0xf), + flags, this); if (pid == -1) throw SysError("cloning builder process"); } else -- cgit v1.2.3