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[3.12] gh-110052: Fix faulthandler for freed tstate (#110069) (#110071)

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gh-110052: Fix faulthandler for freed tstate (#110069)

faulthandler now detected freed interp and freed tstate, and no
longer dereference them.

(cherry picked from commit 2e37a38bcb)
This commit is contained in:
Victor Stinner 2023-10-02 17:44:51 +02:00 • committed by GitHub
parent a2074911ba
commit d0641ab676
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GPG key ID: 4AEE18F83AFDEB23
2 changed files with 38 additions and 12 deletions
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3
Modules/faulthandler.c
View file

@ -176,7 +176,6 @@ faulthandler_dump_traceback(int fd, int all_threads,
PyInterpreterState *interp)
{
static volatile int reentrant = 0;
PyThreadState *tstate;
if (reentrant)
return;
@ -191,7 +190,7 @@ faulthandler_dump_traceback(int fd, int all_threads,
fault if the thread released the GIL, and so this function cannot be
used. Read the thread specific storage (TSS) instead: call
PyGILState_GetThisThreadState(). */
tstate = PyGILState_GetThisThreadState();
PyThreadState *tstate = PyGILState_GetThisThreadState();
if (all_threads) {
(void)_Py_DumpTracebackThreads(fd, NULL, tstate);

47
Python/traceback.c
View file

@ -1218,23 +1218,45 @@ dump_frame(int fd, _PyInterpreterFrame *frame)
PUTS(fd, "\n");
}
static int
tstate_is_freed(PyThreadState *tstate)
{
if (_PyMem_IsPtrFreed(tstate)) {
return 1;
}
if (_PyMem_IsPtrFreed(tstate->interp)) {
return 1;
}
return 0;
}
static int
interp_is_freed(PyInterpreterState *interp)
{
return _PyMem_IsPtrFreed(interp);
}
static void
dump_traceback(int fd, PyThreadState *tstate, int write_header)
{
_PyInterpreterFrame *frame;
unsigned int depth;
if (write_header) {
PUTS(fd, "Stack (most recent call first):\n");
}
frame = tstate->cframe->current_frame;
if (tstate_is_freed(tstate)) {
PUTS(fd, " <tstate is freed>\n");
return;
}
_PyInterpreterFrame *frame = tstate->cframe->current_frame;
if (frame == NULL) {
PUTS(fd, " <no Python frame>\n");
return;
}
depth = 0;
unsigned int depth = 0;
while (1) {
if (MAX_FRAME_DEPTH <= depth) {
PUTS(fd, " ...\n");
@ -1298,9 +1320,6 @@ const char*
_Py_DumpTracebackThreads(int fd, PyInterpreterState *interp,
PyThreadState *current_tstate)
{
PyThreadState *tstate;
unsigned int nthreads;
if (current_tstate == NULL) {
/* _Py_DumpTracebackThreads() is called from signal handlers by
faulthandler.
@ -1316,6 +1335,10 @@ _Py_DumpTracebackThreads(int fd, PyInterpreterState *interp,
current_tstate = PyGILState_GetThisThreadState();
}
if (current_tstate != NULL && tstate_is_freed(current_tstate)) {
return "tstate is freed";
}
if (interp == NULL) {
if (current_tstate == NULL) {
interp = _PyGILState_GetInterpreterStateUnsafe();
@ -1330,14 +1353,18 @@ _Py_DumpTracebackThreads(int fd, PyInterpreterState *interp,
}
assert(interp != NULL);
if (interp_is_freed(interp)) {
return "interp is freed";
}
/* Get the current interpreter from the current thread */
tstate = PyInterpreterState_ThreadHead(interp);
PyThreadState *tstate = PyInterpreterState_ThreadHead(interp);
if (tstate == NULL)
return "unable to get the thread head state";
/* Dump the traceback of each thread */
tstate = PyInterpreterState_ThreadHead(interp);
nthreads = 0;
unsigned int nthreads = 0;
_Py_BEGIN_SUPPRESS_IPH
do
{