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bpo-41710: PyThread_acquire_lock_timed() clamps the timout (GH-28643)

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PyThread_acquire_lock_timed() now clamps the timeout into the
[_PyTime_MIN; _PyTime_MAX] range (_PyTime_t type) if it is too large,
rather than calling Py_FatalError() which aborts the process.

PyThread_acquire_lock_timed() no longer uses
MICROSECONDS_TO_TIMESPEC() to compute sem_timedwait() argument, but
_PyTime_GetSystemClock() and _PyTime_AsTimespec_truncate().

Fix _thread.TIMEOUT_MAX value on Windows: the maximum timeout is
0x7FFFFFFF milliseconds (around 24.9 days), not 0xFFFFFFFF
milliseconds (around 49.7 days).

Set PY_TIMEOUT_MAX to 0x7FFFFFFF milliseconds, rather than 0xFFFFFFFF
milliseconds.

Fix PY_TIMEOUT_MAX overflow test: replace (us >= PY_TIMEOUT_MAX) with
(us > PY_TIMEOUT_MAX).
This commit is contained in:
Victor Stinner 2021-09-30 10:16:51 +02:00 • committed by GitHub
parent a143717003
commit 37b8294d62
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9 changed files with 67 additions and 39 deletions
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22
Python/thread_nt.h
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@ -292,6 +292,10 @@ PyThread_free_lock(PyThread_type_lock aLock)
FreeNonRecursiveMutex(aLock) ;
}
// WaitForSingleObject() documentation: "The time-out value needs to be a
// positive number between 0 and 0x7FFFFFFF." INFINITE is equal to 0xFFFFFFFF.
const DWORD TIMEOUT_MS_MAX = 0x7FFFFFFF;
/*
* Return 1 on success if the lock was acquired
*
@ -309,10 +313,20 @@ PyThread_acquire_lock_timed(PyThread_type_lock aLock,
if (microseconds >= 0) {
milliseconds = microseconds / 1000;
if (microseconds % 1000 > 0)
++milliseconds;
if (milliseconds > PY_DWORD_MAX) {
Py_FatalError("Timeout larger than PY_TIMEOUT_MAX");
// Round milliseconds away from zero
if (microseconds % 1000 > 0) {
milliseconds++;
}
if (milliseconds > (PY_TIMEOUT_T)TIMEOUT_MS_MAX) {
// bpo-41710: PyThread_acquire_lock_timed() cannot report timeout
// overflow to the caller, so clamp the timeout to
// [0, TIMEOUT_MS_MAX] milliseconds.
//
// TIMEOUT_MS_MAX milliseconds is around 24.9 days.
//
// _thread.Lock.acquire() and _thread.RLock.acquire() raise an
// OverflowError if microseconds is greater than PY_TIMEOUT_MAX.
milliseconds = TIMEOUT_MS_MAX;
}
}
else {