RepoMirrors/kpatch
1
0
Fork 0
mirror of https://github.com/dynup/kpatch synced 2025-05-06 09:57:56 +00:00
Code Issues Packages Projects Releases Wiki Activity

create-diff-object: don't mangle .rela.__patchable_function_entries

Browse Source 
kpatch_replace_sections_syms() substitutes the object/function symbols
for the section symbol in the relocation sections. But relocations in
.rela.__patchable_function_entries can point to an instruction ouside
the function. This is because with CALL_OPS enabled, two NOPs are added
before the function entry. __patchable_function_entries needs the
address of the first NOP above the function.

We anyway generate __patchable_function_entries again in
kpatch_create_ftrace_callsite_sections() so we can skip mangling these
relocations

Signed-off-by: Puranjay Mohan <pjy@amazon.com>
This commit is contained in:
Puranjay Mohan 2025-02-07 17:30:05 +00:00
parent 2dc6690892
commit ce8ca2cf68
3 changed files with 20 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
kpatch-build/create-diff-object.c
View File

@ -1639,6 +1639,13 @@ static void kpatch_replace_sections_syms(struct kpatch_elf *kelf)
if (!is_rela_section(relasec) || is_debug_section(relasec))
continue;
/*
* We regenerate __patchable_function_entries from scratch so
* don't bother replacing section symbols in its relasec.
*/
if (is_patchable_function_entries_section(relasec))
continue;
list_for_each_entry(rela, &relasec->relas, list) {
if (rela->sym->type != STT_SECTION || !rela->sym->sec)

12
kpatch-build/kpatch-elf.c
View File

@ -65,6 +65,18 @@ bool is_text_section(struct section *sec)
(sec->sh.sh_flags & SHF_EXECINSTR));
}
bool is_patchable_function_entries_section(struct section *sec)
{
char *name;
if (is_rela_section(sec))
name = sec->base->name;
else
name = sec->name;
return !strncmp(name, "__patchable_function_entries", 28);
}
bool is_debug_section(struct section *sec)
{
char *name;

1
kpatch-build/kpatch-elf.h
View File

@ -136,6 +136,7 @@ struct kpatch_elf {
char *status_str(enum status status);
bool is_rela_section(struct section *sec);
bool is_text_section(struct section *sec);
bool is_patchable_function_entries_section(struct section *sec);
bool is_debug_section(struct section *sec);
struct section *find_section_by_index(struct list_head *list, unsigned int index);