ulimit -t doesn't work in Ubuntu 09.04 (beta) 2.6.28-11-generic

[nguyenthanhvuh]

ulimit -t doesn't work as expected in kernel 2.6.28.

I think it might be some bug imcompatability w/ kernel 2.6.28 --- I want to file a bug to kernel dev group but just want to check here first. Whenever I use kernel 2.6.28 (e.g., compile my own vanilla linux source), the problem occurs. To make sure that it isn't due to my own kernel compilation and settings, I tried on the latest Ubuntu version (Jaunty, beta) w/ kernel 2.6.28 default, problem occurs again (I didn't touch the kernel of Jaunty at all, it's the stock default one).

Everything seems fine w/ kernel 2.6.27 (e.g., Intrepid or Hardy) or lower. Also note that dash / bash doesn't seem to be the problem (i.e., ulimit should work w/ both dash and bash).

Below is an example to reproduce the bug.

file: ulimit_test.sh

#!/bin/bash
ulimit -t 1
perl -e 'while(true){}'
exit 0

sh ulimit_test.sh : expected: process is killed after 1 sec,
but w/ 2.6.28: it doesn't get killed at all -- loop forever.

Update: okay it is a kernel related bug -> http://patchwork.kernel.org/patch/13605/ and a patch is being worked on.

[Leann Ogasawara (leannogasawara)]

Hi,

Thanks for the reference to the patch upstream. I'm pasting the upstream git commit id below for the kernel team to reference. Unfortunately the kernel is currently frozen for the upcoming Jaunty release, but I'll nominate this for a Stable Release Update. Thanks.

ogasawara@yoji:~/linux-2.6$ git log -p 37bebc70d7ad4144c571d74500db3bb26ec0c0eb
commit 37bebc70d7ad4144c571d74500db3bb26ec0c0eb
Author: Oleg Nesterov <email address hidden>
Date: Mon Mar 23 20:34:11 2009 +0100

    posix timers: fix RLIMIT_CPU && fork()

    See http://bugzilla.kernel.org/show_bug.cgi?id=12911

[Manoj Iyer (manjo)]

Can you please test the kernel in http://people.ubuntu.com/~manjo/lp361508-jaunty/ and report back here ?

[nguyenthanhvuh (thanhvu)]

Yes the kernel in http://people.ubuntu.com/~manjo/lp361508-jaunty/ seems to work --- thanks for the quick work.

[Manoj Iyer (manjo)]

Thanks for testing my kernel. In jaunty sru submit queue.

[Manoj Iyer (manjo)]

SRU JUSTIFICATION:

IMPACT: ulimit -t doesn't work in Ubuntu 09.04
FIX: This is a workaround patch for 2.6.28.
TEST: Originator of the bug tested the kernel in
http://people.ubuntu.com/~manjo/lp361508-jaunty/ and reported to work.

[Steve Langasek (vorlon)]

Accepted linux into jaunty-proposed, the package will build now and be available in a few hours. Please test and give feedback here. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you in advance!

[vos_ck (christian-klein1)]

Hi everybody,
I am having exactly the same problem with my x86 kernel.
Linux christian-laptop 2.6.28-11-generic #42-Ubuntu SMP Fri Apr 17 01:57:59 UTC 2009 i686 GNU/Linux
I am running Jaunty with 2.6.28-11.42

I ran the test code from above and it behaves exactly the same. I added the proposed repos to my sources but the error remains the same - probably because I am not running the amd kernel ;o)

I am also getting an error when calling ulimit -n 2048 :
bash: ulimit: open files: cannot modify limit: Operation not permitted

Are those issues related somehow?
Could you please insert the working path to the other kernels as well?

If you need more information just let me know.
Thanks,
Christian

[vos_ck (christian-klein1)]

Hi again,

okay, ulimit -n has nothing to do with this bug. I am so sorry. I just had a typo in my config file. uname -n is now working for me...

But the rest remains the same. ulimit -t 1 does not work on my kernel as well.

Sorry for my mistake.

Chris

[nguyenthanhvuh (thanhvu)]

Can you tell me how to try the kernel image in proposed ? I followed what suggested https://wiki.ubuntu.com/Testing/EnableProposed and created /etc/apt/preferences w/ all of those packages pinned so I don't update all of them automatically. Now how to just install the kernel-image in jaunty proposed ? Thanks

[Steve Beattie (sbeattie)]

I have reproduced the issue that ulimit -t not being applied with the 2.6.28-11.42 version of the kernel in jaunty, and have confirmed that the version of the kernel in jaunty-proposed, 2.6.28-13.44, does indeed fix the issue. Marking verification-done.

[Launchpad Janitor (janitor)]

This bug was fixed in the package linux - 2.6.28-13.44

---------------
linux (2.6.28-13.44) jaunty-proposed; urgency=low

  [ Stefan Bader ]

  * Revert "SAUCE: [jaunty] ALSA: Add retry for Intel8x0 clock measurement"
  * Revert "SAUCE: [jaunty] ALSA: Fix clock and buffer calculations for
    Intel8x0"
  * Revert "SAUCE: [jaunty] ALSA: Fix buffer positions and checks"

linux (2.6.28-12.43) jaunty-proposed; urgency=low

  [ Amit Kucheria ]

  * Enable SYN_COOKIES for iop32x and versatile flavours
    - LP: #361687
  * SAUCE: Quirk for BT USB device on MacbookPro to be reset before use
    - LP: #332443

  [ Brad Figg ]

  * [jaunty] Add missing mvsas (Marvel SAS 6440) module configuration.
    - LP: #352336

  [ Chuck Short ]

  * SAUCE: [USB] Unusual Device support for Gold MP3 Player Energy
    - LP: #125250

  [ Daniel T Chen ]

  * SAUCE: [jaunty] ALSA: Fix buffer positions and checks
    - LP: #345627
  * SAUCE: [jaunty] ALSA: Fix clock and buffer calculations for Intel8x0
    - LP: #345627
  * SAUCE: [jaunty] ALSA: Add retry for Intel8x0 clock measurement
    - LP: #345627

  [ Luke Yelavich ]

  * disable CONFIG_SND_HDA_INPUT_BEEP on amd64 and i386
    - LP: #331589

  [ Makito SHIOKAWA ]

  * [ARM] 5404/1: Fix condition in arm_elf_read_implies_exec() to set
    READ_IMPLIES_EXEC
    - LP: #364358

  [ Manoj Iyer ]

  * SAUCE: Added quirk to fix key release for Samsung NC20
    - LP: #360247

  [ Oleg Nesterov ]

  * posix timers: fix RLIMIT_CPU && fork()
    - LP: #361508

  [ Scott James Remnant ]

  * [Config] Disable libusual and the ub driver
    - LP: #364538

  [ Stefan Bader ]

  * Disable unwanted staging builds
    - LP: #366144
  * Remove prism2_usb driver from ubuntu and use the one from staging
    - LP: #325366
  * SAUCE: Make rtl8187se depend on WIRELESS_EXT
    - LP: #366144
  * Disable CONFIG_RTL8187SE for armel.versatile
    - LP: #366144

  [ Tejun Heo ]

  * libata: handle SEMB signature better
    - LP: #257790

  [ Tim Gardner ]

  * Set USB_SERIAL=m for i386/amd64
    - LP: #345002
  * SAUCE: Jaunty - aic79xx - set reset delay to 5 seconds, down from 15.
    - LP: #79542
  * SAUCE: (drop after 2.6.28) Wifi suspend/resume scan timeout fixes
    - LP: #336055
  * Sony laptop: Sony Vaio laptops do not enable wwan power by default.
    - LP: #364678

  [ Tyler Hicks ]

  * SAUCE: (drop after 2.6.28) eCryptfs: Larger buffer for encrypted
    symlink targets
    - LP: #357345

  [ Upstream Kernel Changes ]

  * V4L/DVB (9999): gspca - zc3xx: Webcam 046d:089d added.
    - LP: #326674
  * V4L/DVB (10044): gspca - pac7311: Webcam 093a:2620 added.
    - LP: #363195
  * hwmon: (it87) Add support for the ITE IT8720F
    - LP: #357766
  * vgacon: Return the upper half of 512 character fonts
    - LP: #355057
  * drm/i915: add support for G41 chipset
    - LP: #365958

 -- Stefan Bader <email address hidden> Mon, 25 May 2009 17:30:40 +0200

[Jeremy Foshee (jeremyfoshee)]

Marking Fix Released as this was simply overlooked earlier.

-JFo