From 1c6d867d78475fd8c6274e2b64ebb27735b6cabf Mon Sep 17 00:00:00 2001 From: Josh Stone Date: Sat, 26 Aug 2023 11:50:16 -0700 Subject: [PATCH] wasi: round up the size for `aligned_alloc` C11 `aligned_alloc` requires that the size be a multiple of the alignment. This is enforced in the wasi-libc emmalloc implementation, which always returns NULL if the size is not a multiple. (The default `MALLOC_IMPL=dlmalloc` does not currently check this.) --- library/std/src/sys/unix/alloc.rs | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/library/std/src/sys/unix/alloc.rs b/library/std/src/sys/unix/alloc.rs index 8604b53983d..af0089978ec 100644 --- a/library/std/src/sys/unix/alloc.rs +++ b/library/std/src/sys/unix/alloc.rs @@ -86,7 +86,11 @@ unsafe fn aligned_malloc(layout: &Layout) -> *mut u8 { } else if #[cfg(target_os = "wasi")] { #[inline] unsafe fn aligned_malloc(layout: &Layout) -> *mut u8 { - libc::aligned_alloc(layout.align(), layout.size()) as *mut u8 + // C11 aligned_alloc requires that the size be a multiple of the alignment. + // Layout already checks that the size rounded up doesn't overflow isize::MAX. + let align = layout.align(); + let size = layout.size().next_multiple_of(align); + libc::aligned_alloc(align, size) as *mut u8 } } else { #[inline]