Speaking of bugs detected by LTP - I'm currently chasing
a race condition in the armv7a kernel between futex locking
by a waiter thread and voluntary termination of the
previous futex owner thread.
Haven't progressed far enough yet to make a report -
but the bug was discovered while attempting to run
testcases/realtime/func/prio-wake/prio-wake in the LTP suite.
On Tue, Nov 11, 2014 at 8:07 AM, Jan Stancek <[email protected]> wrote:
>
>
> ----- Original Message -----
> > From: "Cyril Hrubis" <[email protected]>
> > To: [email protected]
> > Sent: Monday, 10 November, 2014 9:41:08 AM
> > Subject: [LTP] LTP usage survey
> >
> > Hi!
> > I'm working on an article about LTP for lwn.net. It will be a short
> > introduction to the project and to the test library. Generally noting
> > new for most of you.
> >
> > What Jake asked for and I think which will be interesting information
> > is where is LTP used and what bugs it's able to find. This is where I
> > need your help.
> >
> > Please take a few minutes and tell us what do you use LTP for and if
> > it's easy enough point to a bugreports/patches/etc.
>
> Hi,
>
> in scope of my team, it's used on daily basis as part of automated
> sanity/smoke tests for (RHEL) kernel builds. It consists of subset
> of tests, that try to cover as much as possible in limited timeframe
> (e.g. <2 hours). kernel QE runs whole sets (runtests), like
> various stress and long running tests on release candidates.
>
> Since January 2014, there were 125 BZs reported/updated against
> RHEL kernel mentioning "LTP" (case sensitive).
>
> It found all kinds of bugs over last couple years, change in syscall
> behaviour, exposed memory leak, crashes or races. Testcases were not
> always designed to catch that particular issue, which is where "-i"
> parameter comes often handy when trying to debug whether it is kernel
> userspace or test problem.
>
> Here are few (upstream) examples I can think of of top of my head:
> (greping kernel tree for "LTP" will surely find more)
>
> 1. pthread_cond_broadcast revelead issue with futex code:
> commit 69cd9eba38867a493a043bb13eb9b33cad5f1a9a
> Author: Linus Torvalds <[email protected]>
> Date: Tue Apr 8 15:30:07 2014 -0700
> futex: avoid race between requeue and wake
>
> 2. move_pages or migrate_pages found an issue with manual
> page migration:
> commit 27329369c9ecf37771b2a65202cbf5578cff3331
> Author: Johannes Weiner <[email protected]>
> Date: Mon Mar 3 15:38:41 2014 -0800
> mm: page_alloc: exempt GFP_THISNODE allocations from zone fairness
>
> 3. mmapstress proved as reliable reproducer for panics, that started
> after kernel has been compiled with newer gcc:
> commit b6a9b7f6b1f21735a7456d534dc0e68e61359d2c
> Author: Jan Stancek <[email protected]>
> Date: Thu Apr 4 11:35:10 2013 -0700
> mm: prevent mmap_cache race in find_vma()
>
> LTP/lcov is also the partial reason, why there was push to get
> gcov fixed for new gcc -> nice coverage reports for kernel code
> commit 5f41ea0386a53414d688cfcaa321a78310e5f7c1
> Author: Frantisek Hrbata <[email protected]>
> Date: Tue Nov 12 15:11:26 2013 -0800
> gcov: add support for gcc 4.7 gcov format
>
> Maybe a lcov report from full LTP run (e.g. x86_64 2+ NUMA system),
> on latest stable kernel, showing coverage of various kernel subdirs
> would be interesting.
>
> Regards,
> Jan
>
> >
> > --
> > Cyril Hrubis
> > [email protected]
> >
> >
> ------------------------------------------------------------------------------
> > _______________________________________________
> > Ltp-list mailing list
> > [email protected]
> > https://lists.sourceforge.net/lists/listinfo/ltp-list
> >
>
>
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