Reproduction steps:
1. Execute command: iotop -b -n 10 &
2. Execute the command in another session: valgrind /usr/sbin/iotop -b -n 5 > iotop_test

The output information is as follows:
[root@openEuler ~]# valgrind /usr/sbin/iotop -b -n 5 > iotop_test
==13750== Memcheck, a memory error detector
==13750== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==13750== Using Valgrind-3.16.0 and LibVEX; rerun with -h for copyright info
==13750== Command: /usr/sbin/iotop -b -n 5
==13750==
==13750== Conditional jump or move depends on uninitialised value(s)
==13750== at 0x49B2C40: PyUnicode_Decode (unicodeobject.c:3488)
==13750== by 0x49B335B: unicode_new (unicodeobject.c:15465)
==13750== by 0x4982C07: type_call (typeobject.c:1014)
==13750== by 0x492CA17: _PyObject_MakeTpCall (call.c:191)
==13750== by 0x48F1863: _PyObject_VectorcallTstate (abstract.h:116)
==13750== by 0x48F1863: _PyObject_VectorcallTstate (abstract.h:103)
==13750== by 0x48F1863: PyObject_Vectorcall (abstract.h:127)
==13750== by 0x48F1863: call_function (ceval.c:5075)
==13750== by 0x48F1863: _PyEval_EvalFrameDefault (ceval.c:3518)
==13750== by 0x48EAEE7: _PyEval_EvalFrame (pycore_ceval.h:40)
==13750== by 0x48EAEE7: function_code_fastcall (call.c:330)
==13750== by 0x492CBE7: _PyObject_FastCallDictTstate (call.c:118)
==13750== by 0x492CEEB: _PyObject_Call_Prepend (call.c:489)
==13750== by 0x498A007: slot_tp_init (typeobject.c:6964)
==13750== by 0x4982C4F: type_call (typeobject.c:1026)
==13750== by 0x492CA17: _PyObject_MakeTpCall (call.c:191)
==13750== by 0x48F1863: _PyObject_VectorcallTstate (abstract.h:116)
==13750== by 0x48F1863: _PyObject_VectorcallTstate (abstract.h:103)
==13750== by 0x48F1863: PyObject_Vectorcall (abstract.h:127)
==13750== by 0x48F1863: call_function (ceval.c:5075)
==13750== by 0x48F1863: _PyEval_EvalFrameDefault (ceval.c:3518)
==13750==
==13751== Warning: invalid file descriptor 1024 in syscall close()
==13751== Warning: invalid file descriptor 1025 in syscall close()
==13751== Warning: invalid file descriptor 1026 in syscall close()
==13751== Warning: invalid file descriptor 1027 in syscall close()
==13751== Use --log-fd= to select an alternative log fd.
==13751== Warning: invalid file descriptor 1028 in syscall close()
==13751== Warning: invalid file descriptor 1029 in syscall close()
==13752== Warning: invalid file descriptor 1024 in syscall close()
==13752== Warning: invalid file descriptor 1025 in syscall close()
==13752== Warning: invalid file descriptor 1026 in syscall close()
==13752== Warning: invalid file descriptor 1027 in syscall close()
==13752== Use --log-fd= to select an alternative log fd.
==13752== Warning: invalid file descriptor 1028 in syscall close()
==13752== Warning: invalid file descriptor 1029 in syscall close()
==13750==
==13750== HEAP SUMMARY:
==13750== in use at exit: 1,069,715 bytes in 10,017 blocks
==13750== total heap usage: 589,638 allocs, 579,621 frees, 128,672,782 bytes allocated
==13750==
==13750== LEAK SUMMARY:
==13750== definitely lost: 0 bytes in 0 blocks
==13750== indirectly lost: 0 bytes in 0 blocks
==13750== possibly lost: 1,042,483 bytes in 9,894 blocks
==13750== still reachable: 27,232 bytes in 123 blocks
==13750== suppressed: 0 bytes in 0 blocks
==13750== Rerun with --leak-check=full to see details of leaked memory
==13750==
==13750== Use --track-origins=yes to see where uninitialised values come from
==13750== For lists of detected and suppressed errors, rerun with: -s
==13750== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0)

Software version: python3-3.9.9 & python3.9.10  iotop-6.0

The above stack information is in Python 3.9.10 and this problem cannot be reproduced in Python 3.7.


So is it a python3  problem or an iotop problem?  How to fix it.

It is possible that some core developer may get regular valgrind reports, but I would not know who.  I am pretty sure that you should run it at least on the latest release of the 'main' branch, 3.11.0a5, and perhaps even better, the current tip.  There might be a performance patch that was not backported.  (I have no idea what iotop is.)

The latest version is also problematic (Python 3.11.0a5). The above is the output stack information. Here are the steps to reproduce:

1. iotop -b -n 10 &

2. valgrind --leak-check=full /usr/sbin/iotop -b -n 5 > iotop_ test

I also installed Python3.7.9、Python3. 8.5 tested and found no problems.

Posting a thousand line message makes following a discussion extremely difficult.  Move it into an attachment, if you did not do that already, and delete the message by 'editing' it.  As I said, I cannot otherwise respond to this.

Valgrind does not understand Python's custom obmalloc allocator. You have to run valgrind with our suppression rules Misc/valgrind-python.supp to ignore false errors.

Ok, thanks. There is no memory problem exposed when I add --suppressions=Misc/valgrind-python.supp. I will close this issue.