[PULL,31/41] linux-user/elfload: use MAP_FIXED_NOREPLACE in pgb_reserved_va

Message ID 20200707070858.6622-32-alex.bennee@linaro.org
State Accepted
Commit c1f6ad798c7bb328a6f387f2509bf86305383d37
Headers show
Series
  • testing updates (vm, gitlab, misc build fixes)
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Commit Message

Alex Bennée July 7, 2020, 7:08 a.m.
Given we assert the requested address matches what we asked we should
also make that clear in the mmap flags. Otherwise we see failures in
the GitLab environment for some currently unknown but allowable
reason. We use MAP_FIXED_NOREPLACE if we can so we don't just clobber
an existing mapping. Also include the strerror string for a bit more
info on failure.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>


Message-Id: <20200701135652.1366-34-alex.bennee@linaro.org>

-- 
2.20.1

Patch

diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index b5cb21384a1c..7e7f642332dc 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -2294,7 +2294,7 @@  static void pgb_dynamic(const char *image_name, long align)
 static void pgb_reserved_va(const char *image_name, abi_ulong guest_loaddr,
                             abi_ulong guest_hiaddr, long align)
 {
-    const int flags = MAP_ANONYMOUS | MAP_PRIVATE | MAP_NORESERVE;
+    int flags = MAP_ANONYMOUS | MAP_PRIVATE | MAP_NORESERVE;
     void *addr, *test;
 
     if (guest_hiaddr > reserved_va) {
@@ -2307,15 +2307,19 @@  static void pgb_reserved_va(const char *image_name, abi_ulong guest_loaddr,
     /* Widen the "image" to the entire reserved address space. */
     pgb_static(image_name, 0, reserved_va, align);
 
+#ifdef MAP_FIXED_NOREPLACE
+    flags |= MAP_FIXED_NOREPLACE;
+#endif
+
     /* Reserve the memory on the host. */
     assert(guest_base != 0);
     test = g2h(0);
     addr = mmap(test, reserved_va, PROT_NONE, flags, -1, 0);
     if (addr == MAP_FAILED) {
         error_report("Unable to reserve 0x%lx bytes of virtual address "
-                     "space for use as guest address space (check your "
+                     "space (%s) for use as guest address space (check your "
                      "virtual memory ulimit setting or reserve less "
-                     "using -R option)", reserved_va);
+                     "using -R option)", reserved_va, strerror(errno));
         exit(EXIT_FAILURE);
     }
     assert(addr == test);