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| author | Stefan Krah <skrah@bytereef.org> | 2020-03-02 20:22:36 (GMT) |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2020-03-02 20:22:36 (GMT) |
| commit | b3b9ade4a3d3fe00d933bcd8fc5c5c755d1024f9 (patch) | |
| tree | 20c2b9d6a7a68e8c3d8c9bd1f0609bebcb420197 | |
| parent | 2d2f85517f8216146a2f888d1ad4d765b3be2339 (diff) | |
| download | cpython-b3b9ade4a3d3fe00d933bcd8fc5c5c755d1024f9.zip cpython-b3b9ade4a3d3fe00d933bcd8fc5c5c755d1024f9.tar.gz cpython-b3b9ade4a3d3fe00d933bcd8fc5c5c755d1024f9.tar.bz2 | |
bpo-39776: Lock ++interp->tstate_next_unique_id. (GH-18746) (#18746)
- Threads created by PyGILState_Ensure() could have a duplicate tstate->id.
| -rw-r--r-- | Misc/NEWS.d/next/Core and Builtins/2020-03-02-20-12-33.bpo-39776.fNaxi_.rst | 6 | ||||
| -rw-r--r-- | Python/pystate.c | 3 |
2 files changed, 7 insertions, 2 deletions
diff --git a/Misc/NEWS.d/next/Core and Builtins/2020-03-02-20-12-33.bpo-39776.fNaxi_.rst b/Misc/NEWS.d/next/Core and Builtins/2020-03-02-20-12-33.bpo-39776.fNaxi_.rst new file mode 100644 index 0000000..e5a00bd --- /dev/null +++ b/Misc/NEWS.d/next/Core and Builtins/2020-03-02-20-12-33.bpo-39776.fNaxi_.rst @@ -0,0 +1,6 @@ +Fix race condition where threads created by PyGILState_Ensure() could get a +duplicate id. + +This affects consumers of tstate->id like the contextvar caching machinery, +which could return invalid cached objects under heavy thread load (observed +in embedded scenarios). diff --git a/Python/pystate.c b/Python/pystate.c index ebc17ea..4001c63 100644 --- a/Python/pystate.c +++ b/Python/pystate.c @@ -606,13 +606,12 @@ new_threadstate(PyInterpreterState *interp, int init) tstate->context = NULL; tstate->context_ver = 1; - tstate->id = ++interp->tstate_next_unique_id; - if (init) { _PyThreadState_Init(tstate); } HEAD_LOCK(runtime); + tstate->id = ++interp->tstate_next_unique_id; tstate->prev = NULL; tstate->next = interp->tstate_head; if (tstate->next) |