BUG: commit "ARM: Remove __ARCH_WANT_INTERRUPTS_ON_CTXSW on pre-ARMv6 CPUs" breaks armv5 with CONFIG_PREEMPT

Will Deacon will.deacon at arm.com
Thu Jun 20 05:25:27 EDT 2013


Hi Marc,

On Thu, Jun 20, 2013 at 09:43:33AM +0100, Marc Kleine-Budde wrote:
> The problem can be reproduced on several mx28 and an at91sam9263 and
> only occurs of CONFIG_PREEMPT (Preemptible Kernel (Low-Latency Desktop))
> is enabled.
> 
> I have the gut feeling that the "if (irqs_disabled())" check in the
> above patch is not correct for CONFIG_PREEMPT.
> 
> Marc
> 
> [1] The test program creating 150 threads in a row crashes like this:
> > [8]+  Segmentation fault         ./thread_test_c
> > [5]   Illegal instruction        ./thread_test_c
> > [4]   Illegal instruction        ./thread_test_c
> > [2]   Segmentation fault         ./thread_test_c
> > [3]   Illegal instruction        ./thread_test_c
> > [1]   Segmentation fault         ./thread_test_c

Any chance you can make your test available somewhere please? I remember
testing on a 926 when the patch was written, so it could be a bad
interaction with some later changes.

Cheers,

Will



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