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[Bug 1502168] Re: select's FD_ISSET returns true with no data to read

 

apport information

** Tags added: apport-collected

** Description changed:

  Description:    Ubuntu 14.04.3 LTS
  Release:        14.04
  
  Ubuntu 3.13.0-65.105-generic 3.13.11-ckt26
  
    3.13.0-63-generic seems to work fine, but in 3.13.0-65-generic, when
  using select; FD_ISSET returns true even when there is no data on a tty
  with min=0, time=0.  getchar() returns -1
  
    Wondering if it's anything to do with the fix for
  https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1397976 which was
  added in 3.13.0-65.105?
  
  
    Actually noticed this within sox:
  play xx.wav
    hangs due to continually reading the tty (it's not great code - but it showed up the bug).  Whereas:
  play xx.wav < /dev/null
    is fine.
  
    Cheers,
      Tarim
+ --- 
+ ApportVersion: 2.14.1-0ubuntu3.15
+ Architecture: i386
+ AudioDevicesInUse:
+  USER        PID ACCESS COMMAND
+  /dev/snd/controlC0:  tarim      2172 F.... pulseaudio
+ CurrentDesktop: Unity
+ DistroRelease: Ubuntu 14.04
+ HibernationDevice: RESUME=UUID=a6e8d910-2435-40ac-a7da-169eaf499ccd
+ InstallationDate: Installed on 2010-07-17 (1903 days ago)
+ InstallationMedia: Ubuntu 10.04 LTS "Lucid Lynx" - Release i386 (20100429)
+ IwConfig:
+  lo        no wireless extensions.
+  
+  eth0      no wireless extensions.
+ Lsusb:
+  Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
+  Bus 004 Device 002: ID 1c4f:0034 SiGma Micro 
+  Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
+  Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
+  Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
+ MachineType: MICRO-STAR INTERNATIONAL CO.,LTD MS-7530
+ Package: linux (not installed)
+ ProcFB: 0 nouveaufb
+ ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.13.0-65-generic root=UUID=de43ae6e-c38c-45d1-a8eb-2a9a5d55735b ro quiet splash vt.handoff=7
+ ProcVersionSignature: Ubuntu 3.13.0-65.105-generic 3.13.11-ckt26
+ RelatedPackageVersions:
+  linux-restricted-modules-3.13.0-65-generic N/A
+  linux-backports-modules-3.13.0-65-generic  N/A
+  linux-firmware                             1.127.15
+ RfKill:
+  
+ Tags:  trusty
+ Uname: Linux 3.13.0-65-generic i686
+ UpgradeStatus: Upgraded to trusty on 2014-11-28 (308 days ago)
+ UserGroups: adm admin audio cdrom dialout lp lpadmin plugdev sambashare video www-data
+ _MarkForUpload: True
+ dmi.bios.date: 03/04/2009
+ dmi.bios.vendor: American Megatrends Inc.
+ dmi.bios.version: V1.2
+ dmi.board.asset.tag: To Be Filled By O.E.M.
+ dmi.board.name: P7NGM-Digital (MS-7530)
+ dmi.board.vendor: MICRO-STAR INTERNATIONAL CO.,LTD
+ dmi.board.version: 1.0
+ dmi.chassis.asset.tag: To Be Filled By O.E.M.
+ dmi.chassis.type: 3
+ dmi.chassis.vendor: MICRO-STAR INTERNATIONAL CO.,LTD
+ dmi.chassis.version: 1.0
+ dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrV1.2:bd03/04/2009:svnMICRO-STARINTERNATIONALCO.,LTD:pnMS-7530:pvr1.0:rvnMICRO-STARINTERNATIONALCO.,LTD:rnP7NGM-Digital(MS-7530):rvr1.0:cvnMICRO-STARINTERNATIONALCO.,LTD:ct3:cvr1.0:
+ dmi.product.name: MS-7530
+ dmi.product.version: 1.0
+ dmi.sys.vendor: MICRO-STAR INTERNATIONAL CO.,LTD

** Attachment added: "AlsaInfo.txt"
   https://bugs.launchpad.net/bugs/1502168/+attachment/4482804/+files/AlsaInfo.txt

-- 
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https://bugs.launchpad.net/bugs/1502168

Title:
  select's FD_ISSET returns true with no data to read

Status in linux package in Ubuntu:
  Confirmed

Bug description:
  Description:    Ubuntu 14.04.3 LTS
  Release:        14.04

  Ubuntu 3.13.0-65.105-generic 3.13.11-ckt26

    3.13.0-63-generic seems to work fine, but in 3.13.0-65-generic, when
  using select; FD_ISSET returns true even when there is no data on a
  tty with min=0, time=0.  getchar() returns -1

    Wondering if it's anything to do with the fix for
  https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1397976 which was
  added in 3.13.0-65.105?

  
    Actually noticed this within sox:
  play xx.wav
    hangs due to continually reading the tty (it's not great code - but it showed up the bug).  Whereas:
  play xx.wav < /dev/null
    is fine.

    Cheers,
      Tarim
  --- 
  ApportVersion: 2.14.1-0ubuntu3.15
  Architecture: i386
  AudioDevicesInUse:
   USER        PID ACCESS COMMAND
   /dev/snd/controlC0:  tarim      2172 F.... pulseaudio
  CurrentDesktop: Unity
  DistroRelease: Ubuntu 14.04
  HibernationDevice: RESUME=UUID=a6e8d910-2435-40ac-a7da-169eaf499ccd
  InstallationDate: Installed on 2010-07-17 (1903 days ago)
  InstallationMedia: Ubuntu 10.04 LTS "Lucid Lynx" - Release i386 (20100429)
  IwConfig:
   lo        no wireless extensions.
   
   eth0      no wireless extensions.
  Lsusb:
   Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
   Bus 004 Device 002: ID 1c4f:0034 SiGma Micro 
   Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
   Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
   Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
  MachineType: MICRO-STAR INTERNATIONAL CO.,LTD MS-7530
  Package: linux (not installed)
  ProcFB: 0 nouveaufb
  ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.13.0-65-generic root=UUID=de43ae6e-c38c-45d1-a8eb-2a9a5d55735b ro quiet splash vt.handoff=7
  ProcVersionSignature: Ubuntu 3.13.0-65.105-generic 3.13.11-ckt26
  RelatedPackageVersions:
   linux-restricted-modules-3.13.0-65-generic N/A
   linux-backports-modules-3.13.0-65-generic  N/A
   linux-firmware                             1.127.15
  RfKill:
   
  Tags:  trusty
  Uname: Linux 3.13.0-65-generic i686
  UpgradeStatus: Upgraded to trusty on 2014-11-28 (308 days ago)
  UserGroups: adm admin audio cdrom dialout lp lpadmin plugdev sambashare video www-data
  _MarkForUpload: True
  dmi.bios.date: 03/04/2009
  dmi.bios.vendor: American Megatrends Inc.
  dmi.bios.version: V1.2
  dmi.board.asset.tag: To Be Filled By O.E.M.
  dmi.board.name: P7NGM-Digital (MS-7530)
  dmi.board.vendor: MICRO-STAR INTERNATIONAL CO.,LTD
  dmi.board.version: 1.0
  dmi.chassis.asset.tag: To Be Filled By O.E.M.
  dmi.chassis.type: 3
  dmi.chassis.vendor: MICRO-STAR INTERNATIONAL CO.,LTD
  dmi.chassis.version: 1.0
  dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrV1.2:bd03/04/2009:svnMICRO-STARINTERNATIONALCO.,LTD:pnMS-7530:pvr1.0:rvnMICRO-STARINTERNATIONALCO.,LTD:rnP7NGM-Digital(MS-7530):rvr1.0:cvnMICRO-STARINTERNATIONALCO.,LTD:ct3:cvr1.0:
  dmi.product.name: MS-7530
  dmi.product.version: 1.0
  dmi.sys.vendor: MICRO-STAR INTERNATIONAL CO.,LTD

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