kernel-packages team mailing list archive

[Jason Curl <jcurl@xxxxxxxx>]

Public bug reported:

When developing an application using serial ports, behaviour between
process restarts is undefined for particular usb serial port chipsets.

Tested chipsets to fail are:
* pl2303H
* ftdi

Tested chipsets to work are:
* 16550A
* pl2303ra

Attached is a minimal test program to recreate the issue. The program
needs to run twice, the first to create the problem, the second instance
that shows the problem. See the comments at the beginning of the test
program to see expected output and observed output.

Note, flushing, and other workarounds haven't worked, only physically
removing and reinserting the problematic devices between runs (in
particular, the device that is receiving the data over the serial port).

As there appears to be data in a buffer between runs that can't be
properly flushed, I can't say if this is a potential security issue or
not.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: linux-image-3.19.0-49-generic 3.19.0-49.55~14.04.1
ProcVersionSignature: Ubuntu 3.19.0-49.55~14.04.1-generic 3.19.8-ckt12
Uname: Linux 3.19.0-49-generic i686
ApportVersion: 2.14.1-0ubuntu3.19
Architecture: i386
CurrentDesktop: Unity
Date: Sun Feb  7 15:28:42 2016
InstallationDate: Installed on 2016-02-04 (2 days ago)
InstallationMedia:
 
SourcePackage: linux-lts-vivid
UpgradeStatus: No upgrade log present (probably fresh install)

** Affects: linux-lts-vivid (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: apport-bug i386 trusty

** Attachment added: "Test program to recreate the bug"
   https://bugs.launchpad.net/bugs/1542862/+attachment/4566084/+files/kernelbug.c

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https://bugs.launchpad.net/bugs/1542862

Title:
  pl2303h and ftdi serial port bug

Status in linux-lts-vivid package in Ubuntu:
  New

Bug description:
  When developing an application using serial ports, behaviour between
  process restarts is undefined for particular usb serial port chipsets.

  Tested chipsets to fail are:
  * pl2303H
  * ftdi

  Tested chipsets to work are:
  * 16550A
  * pl2303ra

  Attached is a minimal test program to recreate the issue. The program
  needs to run twice, the first to create the problem, the second
  instance that shows the problem. See the comments at the beginning of
  the test program to see expected output and observed output.

  Note, flushing, and other workarounds haven't worked, only physically
  removing and reinserting the problematic devices between runs (in
  particular, the device that is receiving the data over the serial
  port).

  As there appears to be data in a buffer between runs that can't be
  properly flushed, I can't say if this is a potential security issue or
  not.

  ProblemType: Bug
  DistroRelease: Ubuntu 14.04
  Package: linux-image-3.19.0-49-generic 3.19.0-49.55~14.04.1
  ProcVersionSignature: Ubuntu 3.19.0-49.55~14.04.1-generic 3.19.8-ckt12
  Uname: Linux 3.19.0-49-generic i686
  ApportVersion: 2.14.1-0ubuntu3.19
  Architecture: i386
  CurrentDesktop: Unity
  Date: Sun Feb  7 15:28:42 2016
  InstallationDate: Installed on 2016-02-04 (2 days ago)
  InstallationMedia:
   
  SourcePackage: linux-lts-vivid
  UpgradeStatus: No upgrade log present (probably fresh install)

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