[Bug 1914849] Re: mprotect fails after MacOS 11.2 on arm mac

[Roman Bolshakov]

The patch can be used as a workaround for now:
diff --git a/util/osdep.c b/util/osdep.c
index 66d01b9160..76be8c295b 100644
--- a/util/osdep.c
+++ b/util/osdep.c
@@ -110,6 +110,9 @@ int qemu_mprotect_none(void *addr, size_t size)
 {
 #ifdef _WIN32
     return qemu_mprotect__osdep(addr, size, PAGE_NOACCESS);
+#elif defined(__APPLE__) && defined(__arm64__)
+    /* Workaround mprotect (RWX->NONE) issue on Big Sur 11.2 */
+    return 0;
 #else
     return qemu_mprotect__osdep(addr, size, PROT_NONE);
 #endif

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https://bugs.launchpad.net/bugs/1914849

Title:
  mprotect fails after MacOS 11.2 on arm mac

Status in QEMU:
  New

Bug description:
  I got the following error when I ran qemu on arm mac(MacOS 11.2).

  ```
  $ ./qemu-system-x86_64
  qemu-system-x86_64: qemu_mprotect__osdep: mprotect failed: Permission denied
  **
  ERROR:../tcg/tcg.c:844:tcg_region_init: assertion failed: (!rc)
  Bail out! ERROR:../tcg/tcg.c:844:tcg_region_init: assertion failed: (!rc)
  [1]    34898 abort      ./qemu-system-x86_64
  ```

  I tested the same version of qemu on intel mac(MacOS 11.2), but it
  works fine.

  And my friend told me that they did not have this error with MacOS
  11.1.

  So, I think it is CPU architecture or an OS version dependent error.

  
  Environment:

  Qemu commit id: d0dddab40e472ba62b5f43f11cc7dba085dabe71
  OS: MacOS 11.2(20D64)
  Hardware: MacBook Air (M1, 2020)

  
  How to build:

  ```
  mkdir build/
  cd build/
  ../configure --target-list=aarch64-softmmu,x86_64-softmmu
  make
  ```

  
  How to reproduce:

  ```
  ./qemu-system-x86_64
  ```

  
  Error message:

  ```
  $ ./qemu-system-x86_64
  qemu-system-x86_64: qemu_mprotect__osdep: mprotect failed: Permission denied
  **
  ERROR:../tcg/tcg.c:844:tcg_region_init: assertion failed: (!rc)
  Bail out! ERROR:../tcg/tcg.c:844:tcg_region_init: assertion failed: (!rc)
  [1]    34898 abort      ./qemu-system-x86_64
  ```

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