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53 lines
2.4 KiB
53 lines
2.4 KiB
commit 489bbd321e46c110ab9d92fb91725870d7c40491
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Author: Willy Tarreau <w@1wt.eu>
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Date: Tue Sep 24 10:43:03 2019 +0200
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BUG/MEDIUM: checks: make sure the connection is ready before trying to recv
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As identified in issue #278, the backport of commit c594039225 ("BUG/MINOR:
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checks: do not uselessly poll for reads before the connection is up")
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introduced a regression in 2.0 when default checks are enabled (not
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"option tcp-check"), but it did not affect 2.1.
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What happens is that in 2.0 and earlier we have the fd cache which makes
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a speculative call to the I/O functions after an attempt to connect, and
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the __event_srv_chk_r() function was absolutely not designed to be called
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while a connection attempt is still pending. Thus what happens is that the
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test for success/failure expects the verdict to be final before waking up
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the check task, and since the connection is not yet validated, it fails.
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It will usually work over the loopback depending on scheduling, which is
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why it doesn't fail in reg tests.
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In 2.1 after the failed connect(), we subscribe to polling and usually come
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back with a validated connection, so the function is not expected to be
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called before it completes, except if it happens as a side effect of some
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spurious wake calls, which should not have any effect on such a check.
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The other check types are not impacted by this issue because they all
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check for a minimum data length in the buffer, and wait for more data
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until they are satisfied.
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This patch fixes the issue by explicitly checking that the connection
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is established before trying to read or to give a verdict. This way the
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function becomes safe to call regardless of the connection status (even
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if it's still totally ugly).
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This fix must be backported to 2.0.
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(cherry picked from commit 0f0393fc0d2badc5ea329844691f06ba28827f78)
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Signed-off-by: Willy Tarreau <w@1wt.eu>
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diff --git a/src/checks.c b/src/checks.c
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index b088da2e..06f47ad9 100644
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--- a/src/checks.c
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+++ b/src/checks.c
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@@ -875,6 +875,9 @@ static void __event_srv_chk_r(struct conn_stream *cs)
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}
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}
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+ /* the rest of the code below expects the connection to be ready! */
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+ if (!(conn->flags & CO_FL_CONNECTED) && !done)
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+ goto wait_more_data;
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/* Intermediate or complete response received.
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* Terminate string in b_head(&check->bi) buffer.
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