Hi s390 maintainers, This patch mirrors a similar patch for x86, but it has been untested because I do not have a mainframe to compile on :) In 5.4-rc1 the 2 different sha256 implementations for the purgatory resp. for crypto/sha256_generic.c have been consolidated into 1 single shared implementation under lib/crypto/sha256.c . At least on x86 this was causing silent corruption of the purgatory due to a missing memzero_explicit symbol in the purgatory string.c/.o file. With the x86 equivalent of this patch applied a x86 build of 5.4-rc1 now correctly fails: CHK arch/x86/purgatory/purgatory.ro ld: arch/x86/purgatory/purgatory.ro: in function `sha256_transform': sha256.c:(.text+0x1c0c): undefined reference to `memzero_explicit' make[2]: *** [arch/x86/purgatory/Makefile:72: arch/x86/purgatory/kexec-purgatory.c] Error 1 make[1]: *** [scripts/Makefile.build:509: arch/x86/purgatory] Error 2 make: *** [Makefile:1650: arch/x86] Error 2 It would be great if the s390 maintainers can test this equivalent patch on s390. As for fixing the missing memzero_explicit symbol, we are currently discussing making memzero_explicit a static inline wrapper of memset in string.h, so that we do not need to implement it in multiple places. This discussion is Cc-ed to the generic linux-kernel@xxxxxxxxxxxxxxx list, it is happening in the "[PATCH v2 5.4 regression fix] x86/boot: Provide memzero_explicit" thread. Regards, Hans