From c118881ee607dcac661b89893de07cbcbaeb304c Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Sat, 20 Mar 2021 10:57:20 -0600 Subject: [PATCH] tcg: Workaround macOS 11.2 mprotect bug There's a change in mprotect() behaviour [1] in the latest macOS on M1 and it's not yet clear if it's going to be fixed by Apple. As a short-term fix, ignore failures setting up the guard pages. [1] https://gist.github.com/hikalium/75ae822466ee4da13cbbe486498a191f Signed-off-by: Richard Henderson Tested-by: Roman Bolshakov Reviewed-by: Roman Bolshakov Buglink: https://bugs.launchpad.net/qemu/+bug/1914849 Message-Id: <20210320165720.1813545-3-richard.henderson@linaro.org> --- tcg/tcg.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/tcg/tcg.c b/tcg/tcg.c index 88c9e6f8a4..1fbe0b686d 100644 --- a/tcg/tcg.c +++ b/tcg/tcg.c @@ -864,11 +864,15 @@ void tcg_region_init(void) */ for (i = 0; i < region.n; i++) { void *start, *end; - int rc; tcg_region_bounds(i, &start, &end); - rc = qemu_mprotect_none(end, page_size); - g_assert(!rc); + + /* + * macOS 11.2 has a bug (Apple Feedback FB8994773) in which mprotect + * rejects a permission change from RWX -> NONE. Guard pages are + * nice for bug detection but are not essential; ignore any failure. + */ + (void)qemu_mprotect_none(end, page_size); } tcg_region_trees_init();