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| author | mpage <mpage@meta.com> | 2024-04-17 17:19:28 (GMT) |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2024-04-17 17:19:28 (GMT) |
| commit | 0d29302155f49d4d5c7fa34a658ad5a97dd013a2 (patch) | |
| tree | 84ab95a6fa91eb9c4c600fd452e9b6495529bb39 /Python/lock.c | |
| parent | b6c62c79e7d9592ca1ea6b93f6ce3dd3829939d0 (diff) | |
| download | cpython-0d29302155f49d4d5c7fa34a658ad5a97dd013a2.zip cpython-0d29302155f49d4d5c7fa34a658ad5a97dd013a2.tar.gz cpython-0d29302155f49d4d5c7fa34a658ad5a97dd013a2.tar.bz2 | |
gh-117657: Quiet erroneous TSAN reports of data races in `_PySeqLock` (#117955)
Quiet erroneous TSAN reports of data races in `_PySeqLock`
TSAN reports a couple of data races between the compare/exchange in
`_PySeqLock_LockWrite` and the non-atomic loads in `_PySeqLock_{Abandon,Unlock}Write`.
This is another instance of TSAN incorrectly modeling failed compare/exchange
as a write instead of a load.
Diffstat (limited to 'Python/lock.c')
| -rw-r--r-- | Python/lock.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/Python/lock.c b/Python/lock.c index 7d1ead5..91c66df 100644 --- a/Python/lock.c +++ b/Python/lock.c @@ -472,7 +472,7 @@ _PyRWMutex_Unlock(_PyRWMutex *rwmutex) void _PySeqLock_LockWrite(_PySeqLock *seqlock) { - // lock the entry by setting by moving to an odd sequence number + // lock by moving to an odd sequence number uint32_t prev = _Py_atomic_load_uint32_relaxed(&seqlock->sequence); while (1) { if (SEQLOCK_IS_UPDATING(prev)) { @@ -492,14 +492,14 @@ void _PySeqLock_LockWrite(_PySeqLock *seqlock) void _PySeqLock_AbandonWrite(_PySeqLock *seqlock) { - uint32_t new_seq = seqlock->sequence - 1; + uint32_t new_seq = _Py_atomic_load_uint32_relaxed(&seqlock->sequence) - 1; assert(!SEQLOCK_IS_UPDATING(new_seq)); _Py_atomic_store_uint32(&seqlock->sequence, new_seq); } void _PySeqLock_UnlockWrite(_PySeqLock *seqlock) { - uint32_t new_seq = seqlock->sequence + 1; + uint32_t new_seq = _Py_atomic_load_uint32_relaxed(&seqlock->sequence) + 1; assert(!SEQLOCK_IS_UPDATING(new_seq)); _Py_atomic_store_uint32(&seqlock->sequence, new_seq); } |