gh-119999: Fix potential race condition in _Py_ExplicitMergeRefcount
#120000
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…efcount` We need to write to `ob_ref_local` and `ob_tid` before `ob_ref_shared`. Once we mark `ob_ref_shared` as merged, some other thread may free the object because the caller also passes in `-1` as `extra` to give up its only reference.
colesbury
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topic-free-threading
needs backport to 3.13
pimzero
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Jun 3, 2024
…s.*Selector.select` Since f70e1ca, and following PEP-475, `select.select` (and calls to other multiplexing syscalls in the `select` module) should not raise `InterruptedError`. However, if a signal happen and interrupts the `select` syscall in `select.select`, and it raises an exception (uncaught in the signal handler), then the `select` syscall will returns `-EINTR`, `PyErr_CheckSignals()` returns -1 and we don't retry the `select` syscall, the exception being forwarded to the `select.select` caller (in our case, `selectors.SelectSelector.select`. It is an issue if the exception raised in the signal handler is `InterruptedError`: given `selectors.SelectSelector.select` catches this exception and returns an empty list, it is not possible to differentiate between a timeout and a `InterruptedError` exception raised in a signal handler (additionally, this exception is not propagated)
JelleZijlstra
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_Py_ExplicitMergeRefcount_Py_ExplicitMergeRefcount
corona10
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Jun 4, 2024
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Thanks @colesbury for the PR 🌮🎉.. I'm working now to backport this PR to: 3.13. |
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…fcount` (pythonGH-120000) We need to write to `ob_ref_local` and `ob_tid` before `ob_ref_shared`. Once we mark `ob_ref_shared` as merged, some other thread may free the object because the caller also passes in `-1` as `extra` to give up its only reference. (cherry picked from commit 4055577) Co-authored-by: Sam Gross <colesbury@gmail.com>
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GH-120073 is a backport of this pull request to the 3.13 branch. |
colesbury
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Jun 4, 2024
…efcount` (GH-120000) (#120073) We need to write to `ob_ref_local` and `ob_tid` before `ob_ref_shared`. Once we mark `ob_ref_shared` as merged, some other thread may free the object because the caller also passes in `-1` as `extra` to give up its only reference. (cherry picked from commit 4055577) Co-authored-by: Sam Gross <colesbury@gmail.com>
barneygale
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Jun 5, 2024
…fcount` (python#120000) We need to write to `ob_ref_local` and `ob_tid` before `ob_ref_shared`. Once we mark `ob_ref_shared` as merged, some other thread may free the object because the caller also passes in `-1` as `extra` to give up its only reference.
noahbkim
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Jul 11, 2024
…fcount` (python#120000) We need to write to `ob_ref_local` and `ob_tid` before `ob_ref_shared`. Once we mark `ob_ref_shared` as merged, some other thread may free the object because the caller also passes in `-1` as `extra` to give up its only reference.
estyxx
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Jul 17, 2024
…fcount` (python#120000) We need to write to `ob_ref_local` and `ob_tid` before `ob_ref_shared`. Once we mark `ob_ref_shared` as merged, some other thread may free the object because the caller also passes in `-1` as `extra` to give up its only reference.
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We need to write to
ob_ref_localandob_tidbeforeob_ref_shared. Once we markob_ref_sharedas merged, some other thread may free the object because the caller also passes in-1asextrato give up its only reference._Py_ExplicitMergeRefcount#119999