[Openmp-commits] [openmp] 5300a67 - [OpenMP] Fix re-locking hang found in issue 86684 (#88539)

[via Openmp-commits]

Author: Jonathan Peyton
Date: 2024-04-12T15:13:59-05:00
New Revision: 5300a6731e98fbcf7bca68374e934de737166698

URL: https://github.com/llvm/llvm-project/commit/5300a6731e98fbcf7bca68374e934de737166698
DIFF: https://github.com/llvm/llvm-project/commit/5300a6731e98fbcf7bca68374e934de737166698.diff

LOG: [OpenMP] Fix re-locking hang found in issue 86684 (#88539)

This was initially reported here (including stacktraces):
https://stackoverflow.com/questions/78183545/does-compiling-imagick-with-openmp-enabled-in-freebsd-13-2-cause-sched-yield

If `__kmp_register_library_startup()` detects that another instance of
the library is present, `__kmp_is_address_mapped()` is eventually
called. which uses `kmpc_alloc()` to allocate memory. This function
calls `__kmp_entry_thread()` to access the thread-local memory pool,
which is a bad idea during initialization. This macro internally calls
`__kmp_get_global_thread_id_reg()` which sets the bootstrap lock at the
beginning (before calling `__kmp_register_library_startup()`).

The fix is to use `KMP_INTERNAL_MALLOC()`/`KMP_INTERNAL_FREE()` instead
of `kmpc_malloc()`/`kmpc_free()`. `KMP_INTERNAL_MALLOC` and
`KMP_INTERNAL_FREE` do not use any bootstrap locks. They just translate
to `malloc()`/`free()` and are meant to be used during library
initialization before other library-specific allocators have been
initialized.

Fixes: #86684

Added: 
    

Modified: 
    openmp/runtime/src/z_Linux_util.cpp

Removed: 
    


################################################################################
diff  --git a/openmp/runtime/src/z_Linux_util.cpp b/openmp/runtime/src/z_Linux_util.cpp
index be47be0dcec2af..11ce083f4801d3 100644
--- a/openmp/runtime/src/z_Linux_util.cpp
+++ b/openmp/runtime/src/z_Linux_util.cpp
@@ -2141,10 +2141,10 @@ int __kmp_is_address_mapped(void *addr) {
   // We pass from number of vm entry's semantic
   // to size of whole entry map list.
   lstsz = lstsz * 4 / 3;
-  buf = reinterpret_cast<char *>(kmpc_malloc(lstsz));
+  buf = reinterpret_cast<char *>(KMP_INTERNAL_MALLOC(lstsz));
   rc = sysctl(mib, 4, buf, &lstsz, NULL, 0);
   if (rc < 0) {
-    kmpc_free(buf);
+    KMP_INTERNAL_FREE(buf);
     return 0;
   }
 
@@ -2168,7 +2168,7 @@ int __kmp_is_address_mapped(void *addr) {
     }
     lw += cursz;
   }
-  kmpc_free(buf);
+  KMP_INTERNAL_FREE(buf);
 #elif KMP_OS_DRAGONFLY
   char err[_POSIX2_LINE_MAX];
   kinfo_proc *proc;
@@ -2234,12 +2234,12 @@ int __kmp_is_address_mapped(void *addr) {
     return 0;
   }
 
-  buf = kmpc_malloc(sz);
+  buf = KMP_INTERNAL_MALLOC(sz);
 
   while (sz > 0 && (rd = pread(file, buf, sz, 0)) == sz) {
     void *newbuf;
     sz <<= 1;
-    newbuf = kmpc_realloc(buf, sz);
+    newbuf = KMP_INTERNAL_REALLOC(buf, sz);
     buf = newbuf;
   }
 
@@ -2255,7 +2255,7 @@ int __kmp_is_address_mapped(void *addr) {
     }
   }
 
-  kmpc_free(map);
+  KMP_INTERNAL_FREE(map);
   close(file);
   KMP_INTERNAL_FREE(name);
 #elif KMP_OS_DARWIN