[PATCH 3/4] mm/secretmem: zeroize secret pages before kdump

[Jan Sebastian Götte]

On 8/11/26 16:53, David Hildenbrand (Arm) wrote:
> On 7/31/26 18:27, Jan Sebastian Götte wrote:
>> Register a CRASH_ZEROIZE notifier that wipes secretmem folios. As a
>> result, when CONFIG_CRASH_ZEROIZE is set, secretmem areas will be
>> cleared before the kdump kernel is kexec'ed.
> 
> Are you actually using secretmem in your use case? I heard some rumors that
> secretmem isn't used all that much in practice :)

I'm aware nobody is really using secretmem. I decided to build this on 
top of secretmem because it's an existing API that actually kind of fits 
the use case. While I could have added a new API just for this (marking 
userspace memory as wipe-on-crash), making it part of secretmem instead 
gives some additional defense-in-depth protection for both users who 
only need wiping, and for users who only want secretmem's additional 
protection against kernel memory read primitives so I think everyone 
wins here.