fix: prevent SIGSEGV when closing AsyncSession during active stream (#675) - #751
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fix: prevent SIGSEGV when closing AsyncSession during active stream (#675)#751minhduytran wants to merge 1 commit into
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When closing an async streaming response (SSE / long-lived chunked stream) before the server ends it, aclose() must set quit_now before awaiting the perform task. Without this: 1. The perform coroutine never receives the abort signal so aclose() hangs forever on long-lived connections. 2. The curl easy handle may be in a half-initialized streaming state when cleanup runs, causing curl_easy_reset() / curl_easy_cleanup() to free already-freed memory -> SIGSEGV / SIGABRT. Also reorder AsyncSession.close() to set _closed = True before await self.acurl.close(). release_curl() is called as a done-callback on the stream task and checks self._closed to decide whether to call acurl.remove_handle() or curl.close(). If _closed is set after the multi-handle is destroyed, remove_handle() is called on a dead pointer. Fixes lexiforest#675
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The original issue is about sync session, but this PR is about async session. Are they really related? |
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Problem
Two race conditions cause segfaults/hangs when AsyncSession.close() or Response.aclose() is called during an active streaming request.
1. AsyncSession.close() ordering race (SIGSEGV / SIGABRT)
_closed is set AFTER await self.acurl.close(). Between these two lines, the release_curl callback fires, sees _closed == False, and calls acurl.remove_handle() on the already-destroyed multi-handle.
2. Response.aclose() missing abort signal (hang + crash)
aclose() never sets quit_now before awaiting astream_task. For SSE streams, await self.astream_task hangs forever, and the curl handle is left in a partially-initialized state that crashes on cleanup.
Fix
Related
Fixes #675
The Curl.reset = lambda self: None monkey-patch workaround documented in the issue confirms this root cause.
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