[Python-checkins] bpo-33916: Fix bz2 and lzma init when called twice (GH-7843)

[Miss Islington (bot)]

https://github.com/python/cpython/commit/efc6bf66a58e96c12116d65984ac69b0f36f85de
commit: efc6bf66a58e96c12116d65984ac69b0f36f85de
branch: 3.7
author: Miss Islington (bot) <31488909+miss-islington at users.noreply.github.com>
committer: GitHub <noreply at github.com>
date: 2018-06-23T01:53:03-07:00
summary:

bpo-33916: Fix bz2 and lzma init when called twice (GH-7843)


bz2, lzma: When Decompressor.__init__() is called twice, free the old
lock to not leak memory.
(cherry picked from commit 9b7cf757213cf4d7ae1d436d86ad53f5ba362d55)

Co-authored-by: Victor Stinner <vstinner at redhat.com>

files:
A Misc/NEWS.d/next/Library/2018-06-21-11-35-47.bpo-33916.cZgPCD.rst
M Modules/_bz2module.c
M Modules/_lzmamodule.c

diff --git a/Misc/NEWS.d/next/Library/2018-06-21-11-35-47.bpo-33916.cZgPCD.rst b/Misc/NEWS.d/next/Library/2018-06-21-11-35-47.bpo-33916.cZgPCD.rst
new file mode 100644
index 000000000000..65b9d2bf89a5
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2018-06-21-11-35-47.bpo-33916.cZgPCD.rst
@@ -0,0 +1,2 @@
+bz2 and lzma: When Decompressor.__init__() is called twice, free the old
+lock to not leak memory.
diff --git a/Modules/_bz2module.c b/Modules/_bz2module.c
index 0789b6179e52..3890b60b1b87 100644
--- a/Modules/_bz2module.c
+++ b/Modules/_bz2module.c
@@ -634,11 +634,15 @@ _bz2_BZ2Decompressor___init___impl(BZ2Decompressor *self)
 {
     int bzerror;
 
-    self->lock = PyThread_allocate_lock();
-    if (self->lock == NULL) {
+    PyThread_type_lock lock = PyThread_allocate_lock();
+    if (lock == NULL) {
         PyErr_SetString(PyExc_MemoryError, "Unable to allocate lock");
         return -1;
     }
+    if (self->lock != NULL) {
+        PyThread_free_lock(self->lock);
+    }
+    self->lock = lock;
 
     self->needs_input = 1;
     self->bzs_avail_in_real = 0;
diff --git a/Modules/_lzmamodule.c b/Modules/_lzmamodule.c
index 5bcd088d7721..7b501d8202d8 100644
--- a/Modules/_lzmamodule.c
+++ b/Modules/_lzmamodule.c
@@ -1163,11 +1163,15 @@ _lzma_LZMADecompressor___init___impl(Decompressor *self, int format,
     self->lzs.allocator = &self->alloc;
     self->lzs.next_in = NULL;
 
-    self->lock = PyThread_allocate_lock();
-    if (self->lock == NULL) {
+    PyThread_type_lock lock = PyThread_allocate_lock();
+    if (lock == NULL) {
         PyErr_SetString(PyExc_MemoryError, "Unable to allocate lock");
         return -1;
     }
+    if (self->lock != NULL) {
+        PyThread_free_lock(self->lock);
+    }
+    self->lock = lock;
 
     self->check = LZMA_CHECK_UNKNOWN;
     self->needs_input = 1;