Messages in this thread | | | Date | Thu, 17 May 2018 00:46:41 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH 3/3] x86/MCE/AMD: Get address from already initialized block |
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On Tue, May 15, 2018 at 11:39:54AM +0200, Johannes Hirte wrote: > The out-of-bound access happens in get_block_address: > > if (bankp && bankp->blocks) { > struct threshold_block *blockp blockp = &bankp->blocks[block]; > > with block=1. This doesn't exists. I don't even find any array here. > There is a linked list, created in allocate_threshold_blocks. On my > system I get 17 lists with one element each.
Yes, what a mess this is. ;-\
There's no such thing as ->blocks[block] array. We assign simply the threshold_block to it in allocate_threshold_blocks:
per_cpu(threshold_banks, cpu)[bank]->blocks = b;
And I can't say the design of this thing is really friendly but it is still no excuse that I missed that during review. Grrr.
So, Yazen, what really needs to happen here is to iterate the bank->blocks->miscj list to find the block you're looking for and return its address, the opposite to this here:
if (per_cpu(threshold_banks, cpu)[bank]->blocks) { list_add(&b->miscj, &per_cpu(threshold_banks, cpu)[bank]->blocks->miscj); } else { per_cpu(threshold_banks, cpu)[bank]->blocks = b; }
and don't forget to look at ->blocks itself.
And then you need to make sure that searching for block addresses still works when resuming from suspend so that you can avoid the RDMSR IPIs.
Ok?
-- Regards/Gruss, Boris.
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg) --
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