Messages in this thread | | | Date | Thu, 13 Jun 2013 10:51:30 +0200 | From | Marek Szyprowski <> | Subject | Re: [PATCH] dma-mapping: Add BUG_ON for uninitialized dma_ops |
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On 6/12/2013 5:06 PM, Arnd Bergmann wrote: > On Tuesday 11 June 2013, James Bottomley wrote: > > Really, no, it's not a good idea at all. It invites tons of patches > > littering the code with BUG_ONs where we might possibly get a NULL > > dereference. All it does is add extra instructions to a code path for > > no actual benefit. > > > > If you can answer the question: what more information does the BUG_ON > > give you than the NULL deref Oops would not? then it might be > > reasonable. > > The question is if a user can trigger the NULL dereference intentionally, > in which case they might get the kernel to jump into a user-provided > buffer.
I don't any possibility for userspace to alter the ops pointer, so if you think that BUG_ON() approach causes additional overhead then I'm fine to remove it.
Best regards -- Marek Szyprowski Samsung R&D Institute Poland
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