Messages in this thread | | | Date | Fri, 21 Jan 2011 20:43:17 +0100 | From | Ingo Molnar <> | Subject | Re: PPS parport boot lockup: INFO: HARDIRQ-READ-safe -> HARDIRQ-READ-unsafe lock order detected |
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* Linus Torvalds <torvalds@linux-foundation.org> wrote:
> HOWEVER, even then I think you should see the lockdep message as a > problem. The automated toolchain is great because it shows problems > that it thinks might happen - not when they happen, but based on a > simpler theoretical model. Ignoring the error because there is some > rule in place that is hard to explain to the automated toolchain is > the wrong thing to do, because it makes the lockdep automation less > reliable.
Yeah. Also, inevitably the false positives have a higher likelyhood of making it into a released kernel, often because the bugs where there was a real lockup as well got noticed via other means.
It's similar with compiler warnings as well: the questionable ones where GCC is wrong or at least confused accumulate.
Also note that here there's a real lockup here as well, shortly after the lockdep message - the boot never continues, the box keep spewing the PPS debug messages:
[ 76.240020] pps pps0: PPS event at 4294911356 [ 76.244380] pps pps0: PPS event at 1295471377.240018362 [ 76.249608] pps pps0: capture assert seq #2 [ 77.252019] pps pps0: PPS event at 4294911609 [ 77.256379] pps pps0: PPS event at 1295471378.252017372 [ 77.261604] pps pps0: capture assert seq #3 [ 78.264021] pps pps0: PPS event at 4294911862 [ 78.268387] pps pps0: PPS event at 1295471379.264018619 [ 78.273621] pps pps0: capture assert seq #4 [ 79.276018] pps pps0: PPS event at 4294912115 [ 79.280384] pps pps0: PPS event at 1295471380.276016791 [ 79.285619] pps pps0: capture assert seq #5
But nothing happens, the boot never continues.
Thanks,
Ingo
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