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Isolate the tracemalloc Module Between Interpreters #101520

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Isolate the tracemalloc Module Between Interpreters#101520
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3.12only security fixesinterpreter-core(Objects, Python, Grammar, and Parser dirs)topic-subinterpreterstype-featureA feature request or enhancement
@ericsnowcurrently

Description

@ericsnowcurrently
ericsnowcurrently
opened on Feb 2, 2023

(See #100227.)

Currently the tracemalloc module has some state in _PyRuntimeState, including objects, which is shared by all interpreters. Interpreters should be isolated from each other, for a variety of reasons (including the possibility of a per-interpreter GIL). Isolating the module will involve moving some of the state to PyInterpreterState (and, under per-interpreter GIL, guarding other state with a global lock).

Analysis:

(expand)

Allocators

The module installs a custom allocator (using the PEP 445 API
(docs).

(expand)

the allocator functions:

domain func wraps wraps (reentrant) actually wraps

-

 tracemalloc_alloc() <original malloc() or calloc()> <---

-

 tracemalloc_realloc() <original realloc() or free()> <---

-

 tracemalloc_raw_alloc() tracemalloc_alloc() * <original malloc() or calloc()>

-

 tracemalloc_alloc_gil() tracemalloc_alloc() <original malloc() or calloc()>
raw
tracemalloc_raw_malloc() tracemalloc_alloc() <original malloc()> tracemalloc_raw_alloc()
tracemalloc_raw_calloc() tracemalloc_alloc() <original calloc()> tracemalloc_raw_alloc()
tracemalloc_raw_realloc() tracemalloc_realloc() * <original realloc()>
tracemalloc_free() <original free()> <---
mem
obj
tracemalloc_malloc_gil() tracemalloc_alloc_gil() <---
tracemalloc_calloc_gil() tracemalloc_alloc_gil() <---
tracemalloc_realloc_gil() tracemalloc_realloc() <original realloc()>
tracemalloc_free() <original free()> <---

* Note that tracemalloc_raw_alloc() wraps the tracemalloc_alloc() call
with PyGILState_Ensure()/PyGILState_Release().
Likewise for tracemalloc_raw_realloc() where it calls tracemalloc_realloc().
In no other case does an allocator function use the GILState API for any calls.

State

Fields

(expand)

https://github.com/python/cpython/blob/main/Include/internal/pycore_tracemalloc.h#L57-L107
https://github.com/python/cpython/blob/main/Include/internal/pycore_runtime.h#L147

raw

cpython/Include/internal/pycore_tracemalloc.h

Lines 43 to 55 in 0675b8f

struct
#ifdef __GNUC__
__attribute__((packed))
#endif
tracemalloc_frame {
/* filename cannot be NULL: "<unknown>" is used if the Python frame
filename is NULL */
PyObject *filename;
unsigned int lineno;
};
#ifdef _MSC_VER
#pragma pack(pop)
#endif

cpython/Include/internal/pycore_tracemalloc.h

Lines 57 to 64 in 0675b8f

struct tracemalloc_traceback {
Py_uhash_t hash;
/* Number of frames stored */
uint16_t nframe;
/* Total number of frames the traceback had */
uint16_t total_nframe;
struct tracemalloc_frame frames[1];
};

cpython/Include/internal/pycore_tracemalloc.h

Lines 57 to 107 in 0675b8f

struct tracemalloc_traceback {
Py_uhash_t hash;
/* Number of frames stored */
uint16_t nframe;
/* Total number of frames the traceback had */
uint16_t total_nframe;
struct tracemalloc_frame frames[1];
};
struct _tracemalloc_runtime_state {
struct _PyTraceMalloc_Config config;
/* Protected by the GIL */
struct {
PyMemAllocatorEx mem;
PyMemAllocatorEx raw;
PyMemAllocatorEx obj;
} allocators;
#if defined(TRACE_RAW_MALLOC)
PyThread_type_lock tables_lock;
#endif
/* Size in bytes of currently traced memory.
Protected by TABLES_LOCK(). */
size_t traced_memory;
/* Peak size in bytes of traced memory.
Protected by TABLES_LOCK(). */
size_t peak_traced_memory;
/* Hash table used as a set to intern filenames:
PyObject* => PyObject*.
Protected by the GIL */
_Py_hashtable_t *filenames;
/* Buffer to store a new traceback in traceback_new().
Protected by the GIL. */
struct tracemalloc_traceback *traceback;
/* Hash table used as a set to intern tracebacks:
traceback_t* => traceback_t*
Protected by the GIL */
_Py_hashtable_t *tracebacks;
/* pointer (void*) => trace (trace_t*).
Protected by TABLES_LOCK(). */
_Py_hashtable_t *traces;
/* domain (unsigned int) => traces (_Py_hashtable_t).
Protected by TABLES_LOCK(). */
_Py_hashtable_t *domains;
struct tracemalloc_traceback empty_traceback;
Py_tss_t reentrant_key;
};

cpython/Modules/_tracemalloc.c

Lines 54 to 55 in 0675b8f

typedef struct tracemalloc_frame frame_t;
typedef struct tracemalloc_traceback traceback_t;

cpython/Modules/_tracemalloc.c

Lines 69 to 76 in 0675b8f

/* Trace of a memory block */
typedef struct {
/* Size of the memory block in bytes */
size_t size;
/* Traceback where the memory block was allocated */
traceback_t *traceback;
} trace_t;

name type protected by #ifdef notes
config struct _PyTraceMalloc_Config
    . initialized enum {} GIL
    . tracing bool GIL
    . max_nframe int GIL
allocators see PEP 445 (docs)
    . mem PyMemAllocatorEx GIL
    . raw PyMemAllocatorEx GIL
    . obj PyMemAllocatorEx GIL
tables_lock PyThread_type_lock GIL TRACE_RAW_MALLOC
traced_memory size_t tables_lock
peak_traced_memory size_t tables_lock
filenames _Py_hashtable_t * GIL interned; effectively a set of objects
traceback struct tracemalloc_traceback * GIL a temporary buffer
tracebacks _Py_hashtable_t * GIL interned; effectively a set of traceback_t
traces _Py_hashtable_t * tables_lock void-ptr -> trace_t
domains _Py_hashtable_t * tables_lock domain -> _Py_hashtable_t * (per-domain traces)
empty_traceback struct tracemalloc_traceback ???
reentrant_key Py_tss_t ???

notes:

  • each frame in struct tracemalloc_traceback holds a filename object
  • traceback_t is a typedef for struct tracemalloc_traceback
  • frame_t is a typedef for struct tracemalloc_frame

hold objects:

  • filenames
  • traceback (filename in each frame)
  • tracebacks (filename in each frame of each traceback)
  • traces (filename in each frame of each traceback)
  • domains (filename in each frame of each traceback in each domain)

Usage

(expand)

simple:

name context get set
config
    . initialized lifecycle tracemalloc_init()
tracemalloc_deinit()		 tracemalloc_init()
tracemalloc_deinit()
    . tracing module _tracemalloc_is_tracing_impl()
_tracemalloc__get_traces_impl()
_tracemalloc_clear_traces_impl()
_tracemalloc_get_traceback_limit_impl()
_tracemalloc_get_traced_memory_impl()
_tracemalloc_reset_peak_impl()
C-API PyTraceMalloc_Track()
PyTraceMalloc_Untrack()
_PyTraceMalloc_NewReference()
_PyMem_DumpTraceback()
lifecycle tracemalloc_start()
tracemalloc_stop()		 tracemalloc_start()
tracemalloc_stop()
internal tracemalloc_get_traceback()
    . max_nframe module _tracemalloc_get_traceback_limit_impl()
lifecycle tracemalloc_start()
internal traceback_get_frames()
allocators
    . mem lifecycle tracemalloc_start() +
tracemalloc_stop()
    . raw lifecycle tracemalloc_init() +
tracemalloc_start() +
tracemalloc_stop()
internal raw_malloc()
raw_free()
    . obj lifecycle tracemalloc_start() +
tracemalloc_stop()
tables_lock module _tracemalloc__get_traces_impl() +
_tracemalloc_get_tracemalloc_memory_impl() +
_tracemalloc_get_traced_memory_impl() +
_tracemalloc_reset_peak_impl() +
C-API PyTraceMalloc_Track() +
PyTraceMalloc_Untrack() +
_PyTraceMalloc_NewReference() +
lifecycle tracemalloc_init()
tracemalloc_deinit()		 tracemalloc_init() *
tracemalloc_deinit() *
allocator tracemalloc_alloc() +
tracemalloc_realloc() +
tracemalloc_free() +
tracemalloc_realloc_gil() +
tracemalloc_raw_realloc() +
internal tracemalloc_get_traceback() +
tracemalloc_clear_traces() +
traced_memory module _tracemalloc_get_traced_memory_impl()
_tracemalloc_reset_peak_impl()
internal tracemalloc_add_trace() tracemalloc_add_trace()
tracemalloc_remove_trace()
tracemalloc_clear_traces()
peak_traced_memory module _tracemalloc_get_traced_memory_impl() _tracemalloc_reset_peak_impl()
internal tracemalloc_add_trace() tracemalloc_add_trace()
tracemalloc_clear_traces()
filenames module _tracemalloc_get_tracemalloc_memory_impl()
lifecycle tracemalloc_init() *
internal tracemalloc_get_frame()
tracemalloc_clear_traces() +
traceback lifecycle tracemalloc_stop() tracemalloc_start() *
tracemalloc_stop() *
internal traceback_new() +
tracebacks module _tracemalloc_get_tracemalloc_memory_impl()
lifecycle tracemalloc_init() *
tracemalloc_deinit() +
internal traceback_new() +
tracemalloc_clear_traces() +
traces module _tracemalloc__get_traces_impl()
_tracemalloc_get_tracemalloc_memory_impl()
C-API _PyTraceMalloc_NewReference()
lifecycle tracemalloc_deinit() + tracemalloc_init() *
internal tracemalloc_get_traces_table()
tracemalloc_add_trace() (indirect)
tracemalloc_remove_trace() (indirect)
tracemalloc_get_traceback() (indirect)
tracemalloc_clear_traces() +
domains module _tracemalloc__get_traces_impl()
_tracemalloc_get_tracemalloc_memory_impl()
lifecycle tracemalloc_deinit() + tracemalloc_init() *
internal tracemalloc_get_traces_table()
tracemalloc_remove_trace() (indirect)
tracemalloc_get_traceback() (indirect)
tracemalloc_clear_traces() +
tracemalloc_add_trace() +
empty_traceback lifecycle tracemalloc_init() +
internal traceback_new()
reentrant_key lifecycle tracemalloc_init() +
tracemalloc_deinit() +
allocator tracemalloc_alloc_gil() (indirect) +
tracemalloc_realloc_gil() (indirect) +
tracemalloc_raw_alloc() (indirect) +
tracemalloc_raw_realloc() (indirect) +
internal get_reentrant()
set_reentrant() +

* the function allocates/deallocates the value (see below)
+ the function mutates the value (see below)

simple (extraneous):

name context allocate/deallocate get (assert-only)
config.tracing internal tracemalloc_add_trace()
tracemalloc_remove_trace()
tables_lock lifecycle tracemalloc_init()
tracemalloc_deinit()
traced_memory internal tracemalloc_remove_trace()
filenames lifecycle tracemalloc_init()
traceback lifecycle tracemalloc_start()
tracemalloc_stop()		 tracemalloc_start()
tracebacks lifecycle tracemalloc_init()
traces lifecycle tracemalloc_init()
domains lifecycle tracemalloc_init()

mutation of complex fields:

name context initialize finalize clear modify
allocators.mem lifecycle tracemalloc_start()
allocators.raw lifecycle tracemalloc_init()
tracemalloc_start()
allocators.obj lifecycle tracemalloc_start()
tables_lock module _tracemalloc__get_traces_impl()
_tracemalloc_get_tracemalloc_memory_impl()
_tracemalloc_get_traced_memory_impl()
_tracemalloc_reset_peak_impl()
C-API PyTraceMalloc_Track()
PyTraceMalloc_Untrack()
_PyTraceMalloc_NewReference()
allocator tracemalloc_alloc() tracemalloc_alloc()
tracemalloc_realloc()
tracemalloc_free()
tracemalloc_realloc_gil()
tracemalloc_raw_realloc()
internal tracemalloc_clear_traces()
tracemalloc_get_traceback()
filenames internal tracemalloc_clear_traces() tracemalloc_get_frame()
tracemalloc_clear_traces()
lifecycle tracemalloc_deinit()
traceback internal traceback_new()
tracebacks lifecycle tracemalloc_deinit()
internal tracemalloc_clear_traces() traceback_new()
traces lifecycle tracemalloc_deinit()
internal tracemalloc_clear_traces()
domains lifecycle tracemalloc_deinit()
internal tracemalloc_clear_traces() tracemalloc_add_trace()
reentrant_key lifecycle tracemalloc_init() tracemalloc_deinit()
internal set_reentrant()

indirection:

name context direct indirect
allocators.raw lifecycle tracemalloc_start()
tracemalloc_copy_trace()		 raw_malloc()
tracemalloc_stop() raw_free()
internal traceback_new()
tracemalloc_add_trace()
tracemalloc_copy_trace()		 raw_malloc()
traceback_new()
tracemalloc_add_trace()
tracemalloc_remove_trace()		 raw_free()
traces internal tracemalloc_add_trace()
tracemalloc_remove_trace()
tracemalloc_get_traceback()		 tracemalloc_get_traces_table()
domains internal tracemalloc_add_trace()
tracemalloc_remove_trace()
tracemalloc_get_traceback()		 tracemalloc_get_traces_table()
reentrant_key allocator tracemalloc_alloc_gil()
tracemalloc_realloc_gil()
tracemalloc_raw_alloc()
tracemalloc_raw_realloc()		 get_reentrant()
tracemalloc_alloc_gil()
tracemalloc_realloc_gil()
tracemalloc_raw_alloc()
tracemalloc_raw_realloc()		 set_reentrant()

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