| Bug #46308 | LoadPacket stuck in loop | ||
|---|---|---|---|
| Submitted: | 20 Jul 15:36 | Modified: | 5 Aug 14:25 |
| Reporter: | Mark Logan | ||
| Status: | Closed | ||
| Category: | Connector/Net | Severity: | S2 (Serious) |
| Version: | 6.0.4 | OS: | Microsoft Windows (XP) |
| Assigned to: | Target Version: | ||
| Tags: | Load Packet, deadlock, infinite loop | ||
[21 Jul 8:34]
Tonci Grgin
Hi Mark and thanks for your report. I'll leave it open until Wlad's patch for Bug#43678 is released so you can retest.
[29 Jul 13:07]
Bugs System
A patch for this bug has been committed. After review, it may be pushed to the relevant source trees for release in the next version. You can access the patch from: http://lists.mysql.com/commits/79516 731 Vladislav Vaintroub 2009-07-29 fixed potential infinite loop in LoadPacket(), when read from a stream returns 0. (bug#46308)
[5 Aug 14:25]
Tony Bedford
An entry was added to the 6.0.5 and 6.1.1 changelogs: MySQL Connector/NET sometimes hung, without generating an exception. This happened if a read from a stream failed returning a 0, causing the code in LoadPacket() to enter an infinite loop.
Description: Running .NET webservice using connector.net on Windows XP to connect to MySQL(version 5.0.45) on Linux process sometimes deadlocks. No exceptions are thrown. Debugging into source code of MySqlStream.cs line 171: while (leftToRead > 0) { int read = inStream.Read(packet.Buffer, offset, leftToRead); leftToRead -= read; offset += read; } inStream.Read() always returns 0 and leftToRead is > 0 so results in infinte loop. .Net documentation indicates that 0 will be returned if the end of the stream has been reached. Somehow there are still bytes to be read but the Read method indicates end of stream - indicating stream is broken. In this instance infinte loop results. This is similar to: Bug #43678 Reading from a CompressedStream may result in deadlock How to repeat: Error recurrs intermittently. In our testing, web service is only called by 4 other processes (concurrently). Connection to mysql server seems to be breaking somehow. Suggested fix: while (leftToRead > 0) { int read = baseStream.Read(inBuffer, numRead, numToRead); numRead += read; numToRead -= read; if (read == 0 && numToRead > 0) throw new MySqlException("The end of the stream was unexpectedly reached."); }