livepatch/x86: apply alternatives and paravirt patches after relocations
Implement arch_klp_init_object_loaded() for x86, which applies alternatives/paravirt patches. This fixes the order in which relocations and alternatives/paravirt patches are applied. Previously, if a patch module had alternatives or paravirt patches, these were applied first by the module loader before livepatch can apply per-object relocations. The (buggy) sequence of events was: (1) Load patch module (2) Apply alternatives and paravirt patches to patch module * Note that these are applied to the new functions in the patch module (3) Apply per-object relocations to patch module when target module loads. * This clobbers what was written in step 2 This lead to crashes and corruption in general, since livepatch would overwrite or step on previously applied alternative/paravirt patches. The correct sequence of events should be: (1) Load patch module (2) Apply per-object relocations to patch module (3) Apply alternatives and paravirt patches to patch module This is fixed by delaying paravirt/alternatives patching until after relocations are applied. Any .altinstructions or .parainstructions sections are prefixed with ".klp.arch.${objname}" and applied in arch_klp_init_object_loaded(). Signed-off-by:Jessica Yu <jeyu@redhat.com> Acked-by:
Miroslav Benes <mbenes@suse.cz> Signed-off-by:
Jiri Kosina <jkosina@suse.cz>
parent
255e732c
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