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[PATCH v3 for-6.0 2/2] tcg: Workaround macOS 11.2 mprotect bug
From: |
Richard Henderson |
Subject: |
[PATCH v3 for-6.0 2/2] tcg: Workaround macOS 11.2 mprotect bug |
Date: |
Sat, 20 Mar 2021 10:57:20 -0600 |
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
Buglink: https://bugs.launchpad.net/qemu/+bug/1914849
Signed-off-by: Richard Henderson <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();
--
2.25.1