Efraim Flashner <efr...@flashner.co.il> skribis:
> man2 clone: EINVAL: ... on aarch64, child_stack must be a multiple of 16.
>
> * nix/libstore/build.cc (DerivationGoal::startBuilder): When on aarch64,
> when calling clone(), increment the stack by 16.
> ---
> 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 cebc404d1..362b2d91d 100644
> --- a/nix/libstore/build.cc
> +++ b/nix/libstore/build.cc
> @@ -2008,7 +2008,12 @@ 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);
> +// if statements are hard, fix this
> +//#if __AARCH64__
> + pid = clone(childEntry, stack + sizeof(stack) - 16, flags, this);
> +//#else
> +// pid = clone(childEntry, stack + sizeof(stack) - 8, flags, this);
> +//#endif
I think we can make it unconditional. Could you test whether the
attached patch works for aarch64?
Thanks!
Ludo’.
diff --git a/nix/libstore/build.cc b/nix/libstore/build.cc
index cebc404d1..9b7bb5391 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
