SLOB breaks Crypto
in [Kernel]
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From: David Woodhouse on 19 May 2010 07:20 On Wed, 2010-05-19 at 14:08 +0300, Pekka Enberg wrote: > > Acked-by: Pekka Enberg <penberg(a)cs.helsinki.fi> > > Are you sending the patches to Linus or do you want me to pull them in > slab.git? I don't mind. Feel free to apply them to slab.git, but be aware that Herbert wanted to see a patch fixing sparc32 ARCH_SLAB_MINALIGN before the crypto one is applied. Although arguably SLOB was broken on sparc32 even before the crypto patch -- so perhaps that fix shouldn't _have_ to go in first? -- David Woodhouse Open Source Technology Centre David.Woodhouse(a)intel.com Intel Corporation -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Herbert Xu on 19 May 2010 07:50 On Wed, May 19, 2010 at 12:16:45PM +0100, David Woodhouse wrote: > > I don't mind. Feel free to apply them to slab.git, but be aware that > Herbert wanted to see a patch fixing sparc32 ARCH_SLAB_MINALIGN before > the crypto one is applied. > > Although arguably SLOB was broken on sparc32 even before the crypto > patch -- so perhaps that fix shouldn't _have_ to go in first? Well prior to this crypto on sparc32 did work with SLAB/SLUB. If you change it without including the sparc pach, then sparc32 would be broken regardless of which allocator you used. Cheers, -- Visit Openswan at http://www.openswan.org/ Email: Herbert Xu ~{PmV>HI~} <herbert(a)gondor.apana.org.au> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: David Woodhouse on 19 May 2010 07:50 On Wed, 2010-05-19 at 13:32 +0200, Geert Uytterhoeven wrote: > Instead of having (different) defaults in sl[aou]b, perhaps we should > just remove the defaults completely, to ensure all architectures set > ARCH_SLAB_MINALIGN to the correct value? What is 'correct'? The architecture sets it to the minimum value that it can cope with, according to its own alignment constraints (and DMA/cache constraints, in the case of ARCH_KMALLOC_MINALIGN). Some architectures don't _have_ any minimum required alignment, so they have no need to set it. If the architecture _does_ specify a minimum, the allocators must honour it. Otherwise, they're free to do their own thing. And slob chooses to use a smaller alignment than slab and slub do, in accordance with its design and its raison d'être. -- dwmw2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Geert Uytterhoeven on 19 May 2010 07:50 On Wed, May 19, 2010 at 09:14, David Woodhouse <dwmw2(a)infradead.org> wrote: > On Wed, 2010-05-19 at 11:05 +1000, Herbert Xu wrote: >> While this problem wouldn't have occurred, we would instead have >> data corruption/alignment faults on architectures such as sparc32 >> or ARM that require 64-bit alignment for 64-bit objects. > > Yeah, but that's what ARCH_SLAB_MINALIGN is for. > > ARM gets this right, and Dave has already said he's going to fix sparc. Instead of having (different) defaults in sl[aou]b, perhaps we should just remove the defaults completely, to ensure all architectures set ARCH_SLAB_MINALIGN to the correct value? Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert(a)linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Geert Uytterhoeven on 19 May 2010 08:00
On Wed, May 19, 2010 at 13:40, David Woodhouse <dwmw2(a)infradead.org> wrote: > On Wed, 2010-05-19 at 13:32 +0200, Geert Uytterhoeven wrote: >> Instead of having (different) defaults in sl[aou]b, perhaps we should >> just remove the defaults completely, to ensure all architectures set >> ARCH_SLAB_MINALIGN to the correct value? > > What is 'correct'? The architecture sets it to the minimum value that it > can cope with, according to its own alignment constraints (and DMA/cache > constraints, in the case of ARCH_KMALLOC_MINALIGN). > > Some architectures don't _have_ any minimum required alignment, so they > have no need to set it. If the architecture _does_ specify a minimum, > the allocators must honour it. Otherwise, they're free to do their own > thing. And slob chooses to use a smaller alignment than slab and slub > do, in accordance with its design and its raison d'être. Currently 7 out of 20+ architectures set it. Any bets on how many are missing, but should set it? Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert(a)linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |