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| -rw-r--r-- | Misc/README | 2 | ||||
| -rw-r--r-- | Misc/README.valgrind | 71 | ||||
| -rw-r--r-- | Misc/valgrind-python.supp | 216 |
3 files changed, 289 insertions, 0 deletions
diff --git a/Misc/README b/Misc/README index 67d4fd9..af6e8e8 100644 --- a/Misc/README +++ b/Misc/README @@ -24,8 +24,10 @@ pymemcompat.h Memory interface compatibility file. python.man UNIX man page for the python interpreter python-mode.el Emacs mode for editing Python programs README The file you're reading now +README.valgrind Information for Valgrind users, see valgrind-python.supp RFD Request For Discussion about a Python newsgroup RPM (Old) tools to build RPMs SpecialBuilds.txt Describes extra symbols you can set for debug builds setuid-prog.c C helper program for set-uid Python scripts vgrindefs Python configuration for vgrind (a generic pretty printer) +valgrind-python.supp Valgrind suppression file, see README.valgrind diff --git a/Misc/README.valgrind b/Misc/README.valgrind new file mode 100644 index 0000000..b5751ac --- /dev/null +++ b/Misc/README.valgrind @@ -0,0 +1,71 @@ +This document describes some caveats about the use of Valgrind with +Python. Valgrind is used periodically by Python developers to try +to ensure there are no memory leaks or invalid memory reads/writes. + +If you don't want to read about the details of using Valgrind, there +are still two things you must do to suppress the warnings. First, +you must use a suppressions file. One is supplied in +Misc/valgrind-python.supp. Second, you must do one of the following: + + * Uncomment Py_USING_MEMORY_DEBUGGER in Objects/obmalloc.c, + then rebuild Python + * Uncomment the lines in Misc/valgrind-python.supp that + suppress the warnings for PyObject_Free and PyObject_Realloc + +Details: +-------- +Python uses its own allocation scheme on top of malloc called PyMalloc. +Valgrind my show some unexpected results when PyMalloc is used. +Starting with Python 2.3, PyMalloc is used by default. You can disable +PyMalloc when configuring python by adding the --without-pymalloc option. +If you disable PyMalloc, most of the information in this document and +the supplied suppressions file will not be useful. + +If you use valgrind on a default build of Python, you will see +many errors like: + + ==6399== Use of uninitialised value of size 4 + ==6399== at 0x4A9BDE7E: PyObject_Free (obmalloc.c:711) + ==6399== by 0x4A9B8198: dictresize (dictobject.c:477) + +These are expected and not a problem. Tim Peters explains +the situation: + + PyMalloc needs to know whether an arbitrary address is one + that's managed by it, or is managed by the system malloc. + The current scheme allows this to be determined in constant + time, regardless of how many memory areas are under pymalloc's + control. + + The memory pymalloc manages itself is in one or more "arenas", + each a large contiguous memory area obtained from malloc. + The base address of each arena is saved by pymalloc + in a vector, and a field at the start of each arena contains + the index of that arena's base address in that vector. + + Given an arbitrary address, pymalloc computes the arena base + address corresponding to it, then looks at "the index" stored + near there. If the index read up is out of bounds for the + vector of arena base addresses pymalloc maintains, then + pymalloc knows for certain that this address is not under + pymalloc's control. Otherwise the index is in bounds, and + pymalloc compares + + the arena base address stored at that index in the vector + + to + + the computed arena address + + pymalloc controls this arena if and only if they're equal. + + It doesn't matter whether the memory pymalloc reads up ("the + index") is initialized. If it's not initialized, then + whatever trash gets read up will lead pymalloc to conclude + (correctly) that the address isn't controlled by it. + + This determination has to be made on every call to one of + pymalloc's free/realloc entry points, so its speed is critical + (Python allocates and frees dynamic memory at a ferocious rate + -- everything in Python, from integers to "stack frames", + lives in the heap). diff --git a/Misc/valgrind-python.supp b/Misc/valgrind-python.supp new file mode 100644 index 0000000..d9a7d83 --- /dev/null +++ b/Misc/valgrind-python.supp @@ -0,0 +1,216 @@ +# +# This is a valgrind suppression file that should be used when using valgrind. +# +# Here's an example of running valgrind: +# +# cd python/dist/src +# valgrind --tool=memcheck --suppressions=Misc/valgrind-python.supp \ +# ./python -E -tt ./Lib/test/regrtest.py -u bsddb,network +# +# You must edit Objects/obmalloc.c and uncomment Py_USING_MEMORY_DEBUGGER +# to use the preferred suppressions with Py_ADDRESS_IN_RANGE. +# +# If you do not want to recompile Python, you can uncomment +# suppressions for PyObject_Free and PyObject_Realloc. +# +# See Misc/README.valgrind for more information. + +# all tool names: Addrcheck,Memcheck,cachegrind,helgrind,massif +{ + ADDRESS_IN_RANGE/Invalid read of size 4 + Memcheck:Addr4 + fun:Py_ADDRESS_IN_RANGE +} + +{ + ADDRESS_IN_RANGE/Invalid read of size 4 + Memcheck:Value4 + fun:Py_ADDRESS_IN_RANGE +} + +{ + ADDRESS_IN_RANGE/Conditional jump or move depends on uninitialised value + Memcheck:Cond + fun:Py_ADDRESS_IN_RANGE +} + +###{ +### ADDRESS_IN_RANGE/Invalid read of size 4 +### Memcheck:Addr4 +### fun:PyObject_Free +###} +### +###{ +### ADDRESS_IN_RANGE/Invalid read of size 4 +### Memcheck:Value4 +### fun:PyObject_Free +###} +### +###{ +### ADDRESS_IN_RANGE/Conditional jump or move depends on uninitialised value +### Memcheck:Cond +### fun:PyObject_Free +###} + +###{ +### ADDRESS_IN_RANGE/Invalid read of size 4 +### Memcheck:Addr4 +### fun:PyObject_Realloc +###} +### +###{ +### ADDRESS_IN_RANGE/Invalid read of size 4 +### Memcheck:Value4 +### fun:PyObject_Realloc +###} +### +###{ +### ADDRESS_IN_RANGE/Conditional jump or move depends on uninitialised value +### Memcheck:Cond +### fun:PyObject_Realloc +###} + +### +### All the suppressions below are for errors that occur within libraries +### that Python uses. The problems to not appear to be related to Python's +### use of the libraries. +### +{ + GDBM problems, see test_gdbm + Memcheck:Param + write(buf) + fun:write + fun:gdbm_open + +} + +### +### These occur from somewhere within the SSL, when running +### test_socket_sll. They are too general to leave on by default. +### +###{ +### somewhere in SSL stuff +### Memcheck:Cond +### fun:memset +###} +###{ +### somewhere in SSL stuff +### Memcheck:Value4 +### fun:memset +###} +### +###{ +### somewhere in SSL stuff +### Memcheck:Cond +### fun:MD5_Update +###} +### +###{ +### somewhere in SSL stuff +### Memcheck:Value4 +### fun:MD5_Update +###} + +# +# All of these problems come from using test_socket_ssl +# +{ + from test_socket_ssl + Memcheck:Cond + fun:BN_bin2bn +} + +{ + from test_socket_ssl + Memcheck:Cond + fun:BN_num_bits_word +} + +{ + from test_socket_ssl + Memcheck:Value4 + fun:BN_num_bits_word +} + +{ + from test_socket_ssl + Memcheck:Cond + fun:BN_mod_exp_mont_word +} + +{ + from test_socket_ssl + Memcheck:Cond + fun:BN_mod_exp_mont +} + +{ + from test_socket_ssl + Memcheck:Param + write(buf) + fun:write + obj:/usr/lib/libcrypto.so.0.9.7 +} + +{ + from test_socket_ssl + Memcheck:Cond + fun:RSA_verify +} + +{ + from test_socket_ssl + Memcheck:Value4 + fun:RSA_verify +} + +{ + from test_socket_ssl + Memcheck:Value4 + fun:DES_set_key_unchecked +} + +{ + from test_socket_ssl + Memcheck:Value4 + fun:DES_encrypt2 +} + +{ + from test_socket_ssl + Memcheck:Cond + obj:/usr/lib/libssl.so.0.9.7 +} + +{ + from test_socket_ssl + Memcheck:Value4 + obj:/usr/lib/libssl.so.0.9.7 +} + +{ + from test_socket_ssl + Memcheck:Cond + fun:BUF_MEM_grow_clean +} + +{ + from test_socket_ssl + Memcheck:Cond + fun:memcpy + fun:ssl3_read_bytes +} + +{ + from test_socket_ssl + Memcheck:Cond + fun:SHA1_Update +} + +{ + from test_socket_ssl + Memcheck:Value4 + fun:SHA1_Update +} + + |