efraim pushed a commit to branch core-updates in repository guix. commit 77e16733197b8950f6b665be1f69375cb2a7155f Author: Efraim Flashner <efr...@flashner.co.il> Date: Tue Feb 14 21:48:30 2017 +0200
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. --- nix/libstore/build.cc | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/nix/libstore/build.cc b/nix/libstore/build.cc index cebc404..9b7bb53 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