Report error to the caller

Author: vstinner

Include/internal/pycore_mmap.h

@@ -17,26 +17,27 @@ extern "C" {
 #endif
 
 #if defined(HAVE_PR_SET_VMA_ANON_NAME) && defined(__linux__)
-static inline void
+static inline int
 _PyAnnotateMemoryMap(void *addr, size_t size, const char *name)
 {
 #ifndef Py_DEBUG
     if (!_Py_GetConfig()->dev_mode) {
-        return;
+        return 0;
     }
 #endif
     // The name length cannot exceed 80 (including the '\0').
     assert(strlen(name) < 80);
-    int old_errno = errno;
-    prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, (unsigned long)addr, size, name);
-    /* Ignore errno from prctl */
-    /* See: https://bugzilla.redhat.com/show_bug.cgi?id=2302746 */
-    errno = old_errno;
+    int res = prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, (unsigned long)addr, size, name);
+    if (res < 0) {
+        return -1;
+    }
+    return 0;
 }
 #else
-static inline void
+static inline int
 _PyAnnotateMemoryMap(void *Py_UNUSED(addr), size_t Py_UNUSED(size), const char *Py_UNUSED(name))
 {
+    return 0;
 }
 #endif
 

Lib/test/test_mmap.py

@@ -6,6 +6,7 @@
 from test.support.import_helper import import_module
 from test.support.os_helper import TESTFN, unlink
 from test.support.script_helper import assert_python_ok
+import errno
 import unittest
 import os
 import re
@@ -1171,7 +1172,17 @@ def test_set_name(self):
         # Test setting name on anonymous mmap
         m = mmap.mmap(-1, PAGESIZE)
         self.addCleanup(m.close)
-        result = m.set_name('test_mapping')
+        try:
+            result = m.set_name('test_mapping')
+        except OSError as exc:
+            if exc.errno == errno.EINVAL:
+                # gh-142419: On Fedora, prctl(PR_SET_VMA_ANON_NAME) fails with
+                # EINVAL because the kernel option CONFIG_ANON_VMA_NAME is
+                # disabled.
+                # See: https://bugzilla.redhat.com/show_bug.cgi?id=2302746
+                self.skipTest("prctl() failed with EINVAL")
+            else:
+                raise
         self.assertIsNone(result)
 
         # Test name length limit (80 chars including prefix "cpython:mmap:" and '\0')

Modules/mmapmodule.c

@@ -1138,7 +1138,10 @@ mmap_mmap_set_name_impl(mmap_object *self, const char *name)
     if (self->flags & MAP_ANONYMOUS) {
         char buf[80];
         sprintf(buf, "%s%s", prefix, name);
-        _PyAnnotateMemoryMap(self->data, self->size, buf);
+        if (_PyAnnotateMemoryMap(self->data, self->size, buf) < 0) {
+            PyErr_SetFromErrno(PyExc_OSError);
+            return NULL;
+        }
         Py_RETURN_NONE;
     }
     else {
@@ -1993,7 +1996,7 @@ new_mmap_object(PyTypeObject *type, PyObject *args, PyObject *kwdict)
     }
 #ifdef MAP_ANONYMOUS
     if (m_obj->flags & MAP_ANONYMOUS) {
-        _PyAnnotateMemoryMap(m_obj->data, map_size, "cpython:mmap");
+        (void)_PyAnnotateMemoryMap(m_obj->data, map_size, "cpython:mmap");
     }
 #endif
     m_obj->access = (access_mode)access;

Objects/obmalloc.c

@@ -468,7 +468,7 @@ _PyMem_ArenaAlloc(void *Py_UNUSED(ctx), size_t size)
     if (ptr == MAP_FAILED)
         return NULL;
     assert(ptr != NULL);
-    _PyAnnotateMemoryMap(ptr, size, "cpython:pymalloc");
+    (void)_PyAnnotateMemoryMap(ptr, size, "cpython:pymalloc");
     return ptr;
 #else
     return malloc(size);

Python/jit.c

@@ -77,7 +77,7 @@ jit_alloc(size_t size)
     unsigned char *memory = mmap(NULL, size, prot, flags, -1, 0);
     int failed = memory == MAP_FAILED;
     if (!failed) {
-        _PyAnnotateMemoryMap(memory, size, "cpython:jit");
+        (void)_PyAnnotateMemoryMap(memory, size, "cpython:jit");
     }
 #endif
     if (failed) {

Python/perf_jit_trampoline.c

@@ -1086,7 +1086,8 @@ static void* perf_map_jit_init(void) {
         close(fd);
         return NULL;  // Memory mapping failed
     }
-    _PyAnnotateMemoryMap(perf_jit_map_state.mapped_buffer, page_size, "cpython:perf_jit_trampoline");
+    (void)_PyAnnotateMemoryMap(perf_jit_map_state.mapped_buffer, page_size,
+                               "cpython:perf_jit_trampoline");
 #endif
 
     perf_jit_map_state.mapped_size = page_size;

Python/perf_trampoline.c

@@ -291,7 +291,7 @@ new_code_arena(void)
         perf_status = PERF_STATUS_FAILED;
         return -1;
     }
-    _PyAnnotateMemoryMap(memory, mem_size, "cpython:perf_trampoline");
+    (void)_PyAnnotateMemoryMap(memory, mem_size, "cpython:perf_trampoline");
     void *start = &_Py_trampoline_func_start;
     void *end = &_Py_trampoline_func_end;
     size_t code_size = end - start;