Fix FD leak in connSocketBlockingConnect on timeout#3541
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enjoy-binbin merged 1 commit intovalkey-io:unstablefrom Apr 23, 2026
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Fix FD leak in connSocketBlockingConnect on timeout#3541enjoy-binbin merged 1 commit intovalkey-io:unstablefrom
enjoy-binbin merged 1 commit intovalkey-io:unstablefrom
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Assign conn->fd immediately after anetTcpNonBlockConnect() succeeds, so that the caller's connClose() properly cleans up the fd on any subsequent error (e.g., aeWait timeout). Previously, conn->fd was only assigned on success, so a timeout left the fd orphaned — one leak per failed MIGRATE connection attempt. Signed-off-by: Madelyn Olson <madelyneolson@gmail.com>
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xdk-amz
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Apr 20, 2026
Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## unstable #3541 +/- ##
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+ Coverage 76.41% 76.44% +0.02%
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Files 159 159
Lines 79927 79927
============================================
+ Hits 61078 61097 +19
+ Misses 18849 18830 -19
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enjoy-binbin
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I am merging it and added the backport label, let me know if you think otherwise. |
sarthakaggarwal97
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## Summary Fix a file descriptor leak in `connSocketBlockingConnect()` when `aeWait()` times out. ## Bug When `anetTcpNonBlockConnect()` succeeds but `aeWait()` times out (e.g., MIGRATE to an unreachable host), the fd is leaked because it was never assigned to `conn->fd`. The caller's `connClose()` checks `conn->fd != -1` and skips cleanup. ## Fix Assign `conn->fd = fd` immediately after `anetTcpNonBlockConnect()` succeeds, before `aeWait()`. This way the caller's normal `connClose()` cleanup path handles the fd on any error, which is consistent with how the rest of the connection lifecycle works. TLS connections also benefit since `connTLSBlockingConnect` delegates to this function for the TCP layer. ## Reproducer ``` valkey-cli SET key hello # Repeat against unreachable host: for i in $(seq 1 30); do valkey-cli MIGRATE 192.0.2.1 6379 key 0 500; done # Check: /proc/<pid>/fd shows 30 leaked socket fds ``` *This issue was generated by AI but verified, with love, by a human.* Signed-off-by: Madelyn Olson <madelyneolson@gmail.com>
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Summary
Fix a file descriptor leak in
connSocketBlockingConnect()whenaeWait()times out.Bug
When
anetTcpNonBlockConnect()succeeds butaeWait()times out (e.g., MIGRATE to an unreachable host), the fd is leaked because it was never assigned toconn->fd. The caller'sconnClose()checksconn->fd != -1and skips cleanup.Fix
Assign
conn->fd = fdimmediately afteranetTcpNonBlockConnect()succeeds, beforeaeWait(). This way the caller's normalconnClose()cleanup path handles the fd on any error, which is consistent with how the rest of the connection lifecycle works.TLS connections also benefit since
connTLSBlockingConnectdelegates to this function for the TCP layer.Reproducer
This issue was generated by AI but verified, with love, by a human.