Messages in this thread | | | Date | Wed, 16 May 2012 05:44:23 -0700 | Subject | Re: [PATCH 10/11] pstore/ram: Switch to persistent_ram routines | From | Kees Cook <> |
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On Tue, May 15, 2012 at 11:14 PM, Anton Vorontsov <anton.vorontsov@linaro.org> wrote: > Hello Kees, > > On Mon, May 14, 2012 at 03:21:17PM -0700, Kees Cook wrote: > [...] >> > - buf = cxt->virt_addr + (id * cxt->record_size); >> > - memset(buf, '\0', cxt->record_size); >> > + persistent_ram_free_old(cxt->przs[id]); >> >> Hm, I don't think persistent_ram_free_old() is what's wanted here. >> That appears to entirely release the region? I want to make sure the >> memory is cleared first. And will this area come back on a write, or >> does it stay released? > > It just releases ECC-restored memory region (a copy). The original > (persistent) region is still fully reusable after that call.
Ah-ha, okay. So this still needs to clear the memory in the "real" copy then. Thanks for the clarification.
>> > + } >> > + >> > + for (i = 0; i < cxt->max_count; i++) { >> > + size_t sz = cxt->record_size; >> > + phys_addr_t start = cxt->phys_addr + sz * i; >> > + >> > + cxt->przs[i] = persistent_ram_new(start, sz, 0); >> >> persistent_ram_new() is marked as __init, so this is unsafe to call if >> built as a module. I think persistent_ram_new() will need to lose the >> __init marking, or I'm misunderstanding something. > > Um. ramoops' probe routine is also __init. persistent_ram_new is a > part of ramoops module, so their __init functions will be discarded > at the same time. > > ram_console can't be a module, so it is also fine. > > So I think it's all fine.
This is what I get for staring at patches instead of applying them. :) Yeah, if it's all built together, it's no problem. It looked to me like they were in different modules.
>> > +fail_przs: >> > + for (i = 0; cxt->przs[i]; i++) >> > + persistent_ram_free(cxt->przs[i]); >> >> This can lead to a BUG, since persistent_ram_free() doesn't handle >> NULL arguments. > > The for loop has 'cxt->przs[i]' condition. :-)
Okay, fair enough. :)
> Thanks for the review!
Sure thing! Thanks for doing this work; I'm excited to have access in ramoops to the new interfaces. :)
-Kees
-- Kees Cook Chrome OS Security -- 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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