Messages in this thread | | | Date | Sun, 21 Jun 2009 13:20:56 +0300 | Subject | Re: Badness on the Warp | From | Pekka Enberg <> |
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On Sun, Jun 21, 2009 at 7:28 AM, Frans Pop<elendil@planet.nl> wrote: > On Sunday 21 June 2009, Sean MacLennan wrote: >> I found the source of the badness. The backtrace is correct: >> >> uic_init_one > > So that's in arch/powerpc/sysdev/uic.c. > >> ___alloc_bootmem >> ___alloc_bootmem_nopanic >> alloc_arch_preferred_bootmem >> >> In alloc_arch_preferred_bootmem we have: >> >> if (WARN_ON_ONCE(slab_is_available())) >> return kzalloc(size, GFP_NOWAIT); >> >> Since the slab is available (it had better be or the call will return >> NULL), we get the badness message, then a successful return from >> kzalloc. >> >> I believe the author wants something like: >> >> if (slab_is_available()) >> return kzalloc(size, GFP_NOWAIT); >> else >> WARN_ON_ONCE(1); > > Well, I myself have no idea. It could also indicate a bug in the uic code. > > But let's CC some people responsible for this code. Pekka recently added > this WARN that triggers in your case; David and Paul look to be the > people most involved in the uic code. > > Start of the thread is at http://lkml.org/lkml/2009/6/20/165.
The WARN_ON() is there to let us know that someone is doing a bootmem allocation but the slab allocator is already up. So the proper fix here is to use kmalloc() directly in the call-site that triggers this WARN_ON. I'm cc'ing Ben as he has been taking care of the fall-out from my patches on ppc.
Pekka -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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