Messages in this thread | | | From | Kees Cook <> | Date | Fri, 26 Oct 2018 19:16:28 +0100 | Subject | Re: [RFC 6/6] Revert "pstore/ram_core: Do not reset restored zone's position and size" |
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On Fri, Oct 26, 2018 at 7:00 PM, Joel Fernandes (Google) <joel@joelfernandes.org> wrote: > This reverts commit 25b63da64708212985c06c7f8b089d356efdd9cf. > > Due to the commit which is being reverted here, it is not possible to > know if pstore's messages were from a previous boot, or from very old > boots. This creates an awkard situation where its unclear if crash or > other logs are from the previous boot or from very old boots. Also > typically we dump the pstore buffers after one reboot and are interested > in only the previous boot's crash so let us reset the buffer after we > save them. > > Lastly, if we don't zap them, then I think it is possible that part of > the buffer will be from this boot and the other parts will be from > previous boots. So this revert fixes all of this by calling > persistent_ram_zap always.
I like the other patches (comments coming), but not this one: it's very intentional to keep all crashes around until they're explicitly unlinked from the pstore filesystem from userspace. Especially true for catching chains of kernel crashes, or a failed log collection, etc. Surviving multiple reboots is the expected behavior on Chrome OS too.
-- Kees Cook
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