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HPCC-32822 Fix MP protocol error logged indefinitely in loop #19207

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merged 1 commit into from
Oct 18, 2024
Merged

HPCC-32822 Fix MP protocol error logged indefinitely in loop #19207

merged 1 commit into from
Oct 18, 2024

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@jakesmith jakesmith commented Oct 18, 2024 •
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The detection of a MP packet with an invalid header threw an exception that was logged, but did not close the socket. When the client closed the socket, the MP server was notified but because it had nothing left to read of the [bad] header, it saw the invalid protocol error again and rethrew the same error. The epoll handler loop continuously notified the handler of the close event (because it did nothing with it), and the protocol error was continuously output. The socket should be close on this and any other exception. In case these events are too frequent, add a timer to log the protocol errors less frequently, and log the header bytes received to help diagnose what the source of these 'rogue' connections are.

Signed-off-by: Jake Smith [email protected]

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Jira Issue: https://hpccsystems.atlassian.net//browse/HPCC-32822

Jirabot Action Result:
Assigning user: [email protected]
Workflow Transition To: Merge Pending
Updated PR

@jakesmith jakesmith requested a review from ghalliday October 18, 2024 08:37
ghalliday
ghalliday reviewed Oct 18, 2024
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system/mp/mpcomm.cpp
if (periodicTimer.hasElapsed())
{
StringBuffer packetHdrBytes("Packet Header bytes: ");
hexdump2string((byte const *)&hdr, sizeof(hdr), packetHdrBytes);
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Should this be std::min(packetHdrBytes, sizeRead)?

Also, should the number of bytes be logged in the message?

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it is guaranteed to have read exactly sizeof(hdr) at this point, if it was less remaining would be >0 and it wouldn't reach here.

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Also, should the number of bytes be logged in the message?

could make hexdump2string prefix message with # bytes..

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have changed hexdump2string to include # bytes

@jakesmith jakesmith requested a review from ghalliday October 18, 2024 11:27
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in testing, there was another (likely the main) issue that causes repeated tracing of this issue.

After the exception, the socket was left opened.
When the client closed the socket, it hit notifySelected, but had no remaining bytes to read (so didn't read anything), but had a activemsg (with the invalid hdr) so repeated the check and threw another exception.
The epoll notify loop then repeated the notification of the close (0 bytes) and the process repeated infinitely!

@jakesmith jakesmith force-pushed the HPCC-32822-protocol-error branch from cea0719 to 285f454 Compare October 18, 2024 11:54
@jakesmith jakesmith changed the title HPCC-32822 Suppress frequent MP protocol error logging HPCC-32822 Fix MP protocol error logged indefinitely in loop Oct 18, 2024
@jakesmith
HPCC-32822 Fix MP protocol error logged indefinitely in loop
81b3e2e 
The detection of a MP packet with an invalid header threw
an exception that was logged, but did not close the socket.
When the client closed the socket, the MP server was notified
but because it had nothing left to read of the [bad] header,
it saw the invalid protocol error again and rethrew the
same error.
The epoll handler loop continuously notified the handler
of the close event (because it did nothing with it), and
the protocol error was continuosly output.

The socket should be close on this and any other exception.

In case these events are too frequent, add a timer to log
the protocol errors less frequently, and log the header
bytes received to help diagnose what the source of these
'rogue' connections are.

Signed-off-by: Jake Smith <[email protected]>
@jakesmith jakesmith force-pushed the HPCC-32822-protocol-error branch from 285f454 to 81b3e2e Compare October 18, 2024 12:19
@ghalliday ghalliday merged commit afff3f8 into hpcc-systems:candidate-9.8.x Oct 18, 2024
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Jirabot Action Result:
Added fix version: 9.8.32
Workflow Transition: 'Resolve issue'

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