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

Jonathan Peyton · web-flow · commit 5300a6731e98 · 2024-04-12T15:13:59.000-05:00
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
diff --git 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

Original file line number	Diff line number	Diff line change
`@@ -2141,10 +2141,10 @@ int __kmp_is_address_mapped(void *addr) {`
`2141`	`2141`	`// We pass from number of vm entry's semantic`
`2142`	`2142`	`// to size of whole entry map list.`
`2143`	`2143`	`lstsz = lstsz * 4 / 3;`
`2144`		`- buf = reinterpret_cast<char *>(kmpc_malloc(lstsz));`
	`2144`	`+ buf = reinterpret_cast<char *>(KMP_INTERNAL_MALLOC(lstsz));`
`2145`	`2145`	`rc = sysctl(mib, 4, buf, &lstsz, NULL, 0);`
`2146`	`2146`	`if (rc < 0) {`
`2147`		`- kmpc_free(buf);`
	`2147`	`+ KMP_INTERNAL_FREE(buf);`
`2148`	`2148`	`return 0;`
`2149`	`2149`	`}`
`2150`	`2150`
`@@ -2168,7 +2168,7 @@ int __kmp_is_address_mapped(void *addr) {`
`2168`	`2168`	`}`
`2169`	`2169`	`lw += cursz;`
`2170`	`2170`	`}`
`2171`		`- kmpc_free(buf);`
	`2171`	`+ KMP_INTERNAL_FREE(buf);`
`2172`	`2172`	`#elif KMP_OS_DRAGONFLY`
`2173`	`2173`	`char err[_POSIX2_LINE_MAX];`
`2174`	`2174`	`kinfo_proc *proc;`
`@@ -2234,12 +2234,12 @@ int __kmp_is_address_mapped(void *addr) {`
`2234`	`2234`	`return 0;`
`2235`	`2235`	`}`
`2236`	`2236`
`2237`		`- buf = kmpc_malloc(sz);`
	`2237`	`+ buf = KMP_INTERNAL_MALLOC(sz);`
`2238`	`2238`
`2239`	`2239`	`while (sz > 0 && (rd = pread(file, buf, sz, 0)) == sz) {`
`2240`	`2240`	`void *newbuf;`
`2241`	`2241`	`sz <<= 1;`
`2242`		`- newbuf = kmpc_realloc(buf, sz);`
	`2242`	`+ newbuf = KMP_INTERNAL_REALLOC(buf, sz);`
`2243`	`2243`	`buf = newbuf;`
`2244`	`2244`	`}`
`2245`	`2245`
`@@ -2255,7 +2255,7 @@ int __kmp_is_address_mapped(void *addr) {`
`2255`	`2255`	`}`
`2256`	`2256`	`}`
`2257`	`2257`
`2258`		`- kmpc_free(map);`
	`2258`	`+ KMP_INTERNAL_FREE(map);`
`2259`	`2259`	`close(file);`
`2260`	`2260`	`KMP_INTERNAL_FREE(name);`
`2261`	`2261`	`#elif KMP_OS_DARWIN`