Messages in this thread | | | From | HORIGUCHI NAOYA(堀口 直也) <> | Subject | Re: [PATCH] x86/mce: Set PG_hwpoison page flag to avoid the capture kernel panic | Date | Tue, 31 Jan 2023 04:50:12 +0000 |
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On Mon, Jan 30, 2023 at 07:21:15PM +0000, Luck, Tony wrote: > > Although I'm not sure that SGX memory or PMEM pages are expected to be > > included in kdump, but simply setting PageHWPoison does not work for them? > > (Maybe that depends on how kdump handles these types of memory.) > > SGX/TDX pages can't be dumped. They are encrypted with no way for kdump to > get the key. > > PMEM seems pointless (but I don't know what kdump does here). > > > As for HugeTLB, kdump utility should parse the struct page and be aware of > > HugeTLB pages, so maybe setting PageHWPoison on the head page could work. > > Or maybe kdump can take not of the PageHWPoison flag on the sub-page of the > huge page? It depends on whether there is any benefit to the dump to include the > not-poisoned parts of a huge page.
I think that many kdump users filter out HugeTLB pages (setting dump_level to filter "User pages") to reduce the size of kdump. User pages are not much helpful to investigate kernel problems, so filtering all sub-pages in hwpoisoned hugepage seems to me not so harmful.
I don't say that saving healthy subpages has no benefit, but I don't know much about usecases where user pages in kdump file help.
Thanks, Naoya Horiguchi | |