RepoMirrors/kpatch
1
0
Fork 0
mirror of https://github.com/dynup/kpatch synced 2025-05-04 17:07:56 +00:00
Code Issues Packages Projects Releases Wiki Activity

replace section symbols before correlating

Browse Source 
The correlation logic could get confused if it compares two relas whose
symbols haven't been converted from section symbols to object or
function symbols.  So we should replace section symbols for both the
base and the patched object before correlating, so that it can compare
the function and object symbols rather than the section symbols.

This is also a prerequisite for dealing properly with gcc's renaming of
static local variables, because relas which reference static locals
usually use section symbols.
This commit is contained in:
Josh Poimboeuf 2014-07-24 11:28:51 -05:00
parent ce8bb40fc0
commit 402911b949
1 changed files with 10 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
kpatch-build/create-diff-object.c
View File

@ -796,6 +796,13 @@ void rela_insn(struct section *sec, struct rela *rela, struct insn *insn)
}
}
/*
* Mangle the relas a little. The compiler will sometimes use section symbols
* to reference local objects and functions rather than the object or function
* symbols themselves. We substitute the object/function symbols for the
* section symbol in this case so that the relas can be properly correlated and
* so that the existing object/function in vmlinux can be linked to.
*/
void kpatch_replace_sections_syms(struct kpatch_elf *kelf)
{
struct section *sec;
@ -2311,9 +2318,12 @@ int main(int argc, char *argv[])
kpatch_check_program_headers(kelf_base->elf);
kpatch_check_program_headers(kelf_patched->elf);
kpatch_replace_sections_syms(kelf_base);
kpatch_replace_sections_syms(kelf_patched);
kpatch_rename_mangled_functions(kelf_base, kelf_patched);
kpatch_correlate_elfs(kelf_base, kelf_patched);
/*
* After this point, we don't care about kelf_base anymore.
* We access its sections via the twin pointers in the
@ -2323,15 +2333,6 @@ int main(int argc, char *argv[])
kpatch_elf_teardown(kelf_base);
kpatch_elf_free(kelf_base);
/*
* Mangle the relas a little. The compiler will sometimes
* use section symbols to reference local objects and functions
* rather than the object or function symbols themselves.
* We substitute the object/function symbols for the section
* symbol in this case so that the existing object/function
* in vmlinux can be linked to.
*/
kpatch_replace_sections_syms(kelf_patched);
kpatch_mark_ignored_funcs_same(kelf_patched);
kpatch_process_special_sections(kelf_patched);