From ee338a256ee8dff064fd3920a2efe642ef1d3cfa Mon Sep 17 00:00:00 2001 From: Stefano Brivio Date: Thu, 11 Apr 2024 17:48:23 +0200 Subject: pasta, util: Align stack area for clones to maximum natural alignment Given that we use this stack pointer as a location to store arbitrary data types from the cloned process, we need to guarantee that its alignment matches any of those possible data types. runsisi reports that pasta gets a SIGBUS in pasta_open_ns() on aarch64, where the alignment requirement for stack pointers is a 16 bytes (same as the size of a long double), and similar requirements actually apply to most architectures we run on. Reported-by: runsisi Link: https://bugs.passt.top/show_bug.cgi?id=85 Signed-off-by: Stefano Brivio Reviewed-by: David Gibson --- util.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'util.h') diff --git a/util.h b/util.h index 7c261d7..8c37729 100644 --- a/util.h +++ b/util.h @@ -9,6 +9,7 @@ #include #include #include +#include #include #include @@ -116,7 +117,8 @@ int do_clone(int (*fn)(void *), char *stack_area, size_t stack_size, int flags, void *arg); #define NS_CALL(fn, arg) \ do { \ - char ns_fn_stack[NS_FN_STACK_SIZE]; \ + char ns_fn_stack[NS_FN_STACK_SIZE] \ + __attribute__ ((aligned(__alignof__(max_align_t)))); \ \ do_clone((fn), ns_fn_stack, sizeof(ns_fn_stack), \ CLONE_VM | CLONE_VFORK | CLONE_FILES | SIGCHLD,\ -- cgit v1.2.3