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Revert "create-diff-object: add jump label support" 

This reverts commit 87c64519fc.

The jump label support doesn't work with upstream livepatch.  Joe
Lawrence found the following ordering issue:

load_module

  apply_relocations

    /* Livepatch relocation sections are applied by livepatch */
    if (info->sechdrs[i].sh_flags & SHF_RELA_LIVEPATCH)
            continue;

  post_relocation
    module_finalize
      jump_label_apply_nops        << crash

  ...

  do_init_module
    do_one_initcall(mod->init)
      __init patch_init [kpatch-patch]
        klp_register_patch
          klp_init_patch
            klp_init_object
              klp_init_object_loaded
                klp_write_object_relocations

So jump_label_apply_nops() is called *before*
klp_write_object_relocations() has had a chance to write the klp
relocations (.klp.rela.kvm_intel.__jump_table, for example).

We need to resolve this upstream first.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
This commit is contained in:
Josh Poimboeuf 2019-02-19 16:10:54 -06:00
parent b4e6085b6d
commit 09ee03f3df
3 changed files with 9 additions and 44 deletions
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26
kpatch-build/create-diff-object.c
View File

@ -1771,21 +1771,6 @@ static int ex_table_group_size(struct kpatch_elf *kelf, int offset)
return size; return size;
} }
static int jump_table_group_size(struct kpatch_elf *kelf, int offset)
{
static int size = 0;
char *str;
if (!size) {
str = getenv("JUMP_STRUCT_SIZE");
if (!str)
ERROR("JUMP_STRUCT_SIZE not set");
size = atoi(str);
}
return size;
}
#ifdef __x86_64__ #ifdef __x86_64__
static int parainstructions_group_size(struct kpatch_elf *kelf, int offset) static int parainstructions_group_size(struct kpatch_elf *kelf, int offset)
{ {
@ -1905,10 +1890,6 @@ static struct special_section special_sections[] = {
.name = "__ex_table", /* must come after .fixup */ .name = "__ex_table", /* must come after .fixup */
.group_size = ex_table_group_size, .group_size = ex_table_group_size,
}, },
{
.name = "__jump_table",
.group_size = jump_table_group_size,
},
#ifdef __x86_64__ #ifdef __x86_64__
{ {
.name = ".smp_locks", .name = ".smp_locks",
@ -2451,11 +2432,12 @@ static void kpatch_process_special_sections(struct kpatch_elf *kelf)
* The following special sections aren't supported, so make sure we * The following special sections aren't supported, so make sure we
* don't ever try to include them. Otherwise the kernel will see the * don't ever try to include them. Otherwise the kernel will see the
* jump table during module loading and get confused. Generally it * jump table during module loading and get confused. Generally it
* should be safe to exclude them, it just means that tracepoints won't * should be safe to exclude them, it just means that you can't modify
* work in a patched function. * jump labels and enable tracepoints in a patched function.
*/ */
list_for_each_entry(sec, &kelf->sections, list) { list_for_each_entry(sec, &kelf->sections, list) {
if (strcmp(sec->name, "__tracepoints") && if (strcmp(sec->name, "__jump_table") &&
strcmp(sec->name, "__tracepoints") &&
strcmp(sec->name, "__tracepoints_ptrs") && strcmp(sec->name, "__tracepoints_ptrs") &&
strcmp(sec->name, "__tracepoints_strings")) strcmp(sec->name, "__tracepoints_strings"))
continue; continue;

25
kpatch-build/kpatch-build
View File

@ -227,40 +227,33 @@ gcc_version_check() {
} }
find_special_section_data_ppc64le() { find_special_section_data_ppc64le() {
[[ "$CONFIG_JUMP_LABEL" -eq 0 ]] && AWK_OPTIONS="-vskip_j=1"
SPECIAL_VARS="$(readelf -wi "$VMLINUX" | SPECIAL_VARS="$(readelf -wi "$VMLINUX" |
gawk --non-decimal-data ' gawk --non-decimal-data '
BEGIN { f = b = e = j = 0 } BEGIN { f = b = e = 0 }
# Set state if name matches # Set state if name matches
f == 0 && /DW_AT_name.* fixup_entry[[:space:]]*$/ {f = 1; next} f == 0 && /DW_AT_name.* fixup_entry[[:space:]]*$/ {f = 1; next}
b == 0 && /DW_AT_name.* bug_entry[[:space:]]*$/ {b = 1; next} b == 0 && /DW_AT_name.* bug_entry[[:space:]]*$/ {b = 1; next}
e == 0 && /DW_AT_name.* exception_table_entry[[:space:]]*$/ {e = 1; next} e == 0 && /DW_AT_name.* exception_table_entry[[:space:]]*$/ {e = 1; next}
j == 0 && /DW_AT_name.* jump_entry[[:space:]]*$/ {j = 1; next}
# Reset state unless this abbrev describes the struct size # Reset state unless this abbrev describes the struct size
f == 1 && !/DW_AT_byte_size/ { f = 0; next } f == 1 && !/DW_AT_byte_size/ { f = 0; next }
b == 1 && !/DW_AT_byte_size/ { b = 0; next } b == 1 && !/DW_AT_byte_size/ { b = 0; next }
e == 1 && !/DW_AT_byte_size/ { e = 0; next } e == 1 && !/DW_AT_byte_size/ { e = 0; next }
j == 1 && !/DW_AT_byte_size/ { j = 0; next }
# Now that we know the size, stop parsing for it # Now that we know the size, stop parsing for it
f == 1 {printf("export FIXUP_STRUCT_SIZE=%d\n", $4); f = 2} f == 1 {printf("export FIXUP_STRUCT_SIZE=%d\n", $4); f = 2}
b == 1 {printf("export BUG_STRUCT_SIZE=%d\n", $4); b = 2} b == 1 {printf("export BUG_STRUCT_SIZE=%d\n", $4); b = 2}
e == 1 {printf("export EX_STRUCT_SIZE=%d\n", $4); e = 2} e == 1 {printf("export EX_STRUCT_SIZE=%d\n", $4); e = 2}
j == 1 {printf("export JUMP_STRUCT_SIZE=%d\n", $4); j = 2}
# Bail out once we have everything # Bail out once we have everything
f == 2 && b == 2 && e == 2 && (j == 2 || skip_j) {exit}')" f == 2 && b == 2 && e == 2 {exit}')"
[[ -n "$SPECIAL_VARS" ]] && eval "$SPECIAL_VARS" [[ -n "$SPECIAL_VARS" ]] && eval "$SPECIAL_VARS"
[[ -z "$FIXUP_STRUCT_SIZE" ]] && die "can't find special struct fixup_entry size" [[ -z "$FIXUP_STRUCT_SIZE" ]] && die "can't find special struct fixup_entry size"
[[ -z "$BUG_STRUCT_SIZE" ]] && die "can't find special struct bug_entry size" [[ -z "$BUG_STRUCT_SIZE" ]] && die "can't find special struct bug_entry size"
[[ -z "$EX_STRUCT_SIZE" ]] && die "can't find special struct exception_table_entry size" [[ -z "$EX_STRUCT_SIZE" ]] && die "can't find special struct exception_table_entry size"
[[ -z "$JUMP_STRUCT_SIZE" && "$CONFIG_JUMP_LABEL" -ne 0 ]] && die "can't find special struct jump_entry size"
return return
} }
@ -273,13 +266,12 @@ find_special_section_data() {
[[ "$CONFIG_PARAVIRT" -eq 0 ]] && AWK_OPTIONS="-vskip_p=1" [[ "$CONFIG_PARAVIRT" -eq 0 ]] && AWK_OPTIONS="-vskip_p=1"
[[ "$CONFIG_UNWINDER_ORC" -eq 0 ]] && AWK_OPTIONS="$AWK_OPTIONS -vskip_o=1" [[ "$CONFIG_UNWINDER_ORC" -eq 0 ]] && AWK_OPTIONS="$AWK_OPTIONS -vskip_o=1"
[[ "$CONFIG_JUMP_LABEL" -eq 0 ]] && AWK_OPTIONS="$AWK_OPTIONS -vskip_j=1"
# If $AWK_OPTIONS are blank gawk would treat "" as a blank script # If $AWK_OPTIONS are blank gawk would treat "" as a blank script
# shellcheck disable=SC2086 # shellcheck disable=SC2086
SPECIAL_VARS="$(readelf -wi "$VMLINUX" | SPECIAL_VARS="$(readelf -wi "$VMLINUX" |
gawk --non-decimal-data $AWK_OPTIONS ' gawk --non-decimal-data $AWK_OPTIONS '
BEGIN { a = b = p = e = o = j = 0 } BEGIN { a = b = p = e = o = 0 }
# Set state if name matches # Set state if name matches
a == 0 && /DW_AT_name.* alt_instr[[:space:]]*$/ {a = 1; next} a == 0 && /DW_AT_name.* alt_instr[[:space:]]*$/ {a = 1; next}
@ -287,7 +279,6 @@ find_special_section_data() {
p == 0 && /DW_AT_name.* paravirt_patch_site[[:space:]]*$/ {p = 1; next} p == 0 && /DW_AT_name.* paravirt_patch_site[[:space:]]*$/ {p = 1; next}
e == 0 && /DW_AT_name.* exception_table_entry[[:space:]]*$/ {e = 1; next} e == 0 && /DW_AT_name.* exception_table_entry[[:space:]]*$/ {e = 1; next}
o == 0 && /DW_AT_name.* orc_entry[[:space:]]*$/ {o = 1; next} o == 0 && /DW_AT_name.* orc_entry[[:space:]]*$/ {o = 1; next}
j == 0 && /DW_AT_name.* jump_entry[[:space:]]*$/ {j = 1; next}
# Reset state unless this abbrev describes the struct size # Reset state unless this abbrev describes the struct size
a == 1 && !/DW_AT_byte_size/ { a = 0; next } a == 1 && !/DW_AT_byte_size/ { a = 0; next }
@ -295,7 +286,6 @@ find_special_section_data() {
p == 1 && !/DW_AT_byte_size/ { p = 0; next } p == 1 && !/DW_AT_byte_size/ { p = 0; next }
e == 1 && !/DW_AT_byte_size/ { e = 0; next } e == 1 && !/DW_AT_byte_size/ { e = 0; next }
o == 1 && !/DW_AT_byte_size/ { o = 0; next } o == 1 && !/DW_AT_byte_size/ { o = 0; next }
j == 1 && !/DW_AT_byte_size/ { j = 0; next }
# Now that we know the size, stop parsing for it # Now that we know the size, stop parsing for it
a == 1 {printf("export ALT_STRUCT_SIZE=%d\n", $4); a = 2} a == 1 {printf("export ALT_STRUCT_SIZE=%d\n", $4); a = 2}
@ -303,10 +293,9 @@ find_special_section_data() {
p == 1 {printf("export PARA_STRUCT_SIZE=%d\n", $4); p = 2} p == 1 {printf("export PARA_STRUCT_SIZE=%d\n", $4); p = 2}
e == 1 {printf("export EX_STRUCT_SIZE=%d\n", $4); e = 2} e == 1 {printf("export EX_STRUCT_SIZE=%d\n", $4); e = 2}
o == 1 {printf("export ORC_STRUCT_SIZE=%d\n", $4); o = 2} o == 1 {printf("export ORC_STRUCT_SIZE=%d\n", $4); o = 2}
j == 1 {printf("export JUMP_STRUCT_SIZE=%d\n", $4); j = 2}
# Bail out once we have everything # Bail out once we have everything
a == 2 && b == 2 && (p == 2 || skip_p) && e == 2 && (o == 2 || skip_o) && (j == 2 || skip_j) {exit}')" a == 2 && b == 2 && (p == 2 || skip_p) && e == 2 && (o == 2 || skip_o) {exit}')"
[[ -n "$SPECIAL_VARS" ]] && eval "$SPECIAL_VARS" [[ -n "$SPECIAL_VARS" ]] && eval "$SPECIAL_VARS"
@ -315,7 +304,6 @@ find_special_section_data() {
[[ -z "$EX_STRUCT_SIZE" ]] && die "can't find special struct paravirt_patch_site size" [[ -z "$EX_STRUCT_SIZE" ]] && die "can't find special struct paravirt_patch_site size"
[[ -z "$PARA_STRUCT_SIZE" && "$CONFIG_PARAVIRT" -ne 0 ]] && die "can't find special struct paravirt_patch_site size" [[ -z "$PARA_STRUCT_SIZE" && "$CONFIG_PARAVIRT" -ne 0 ]] && die "can't find special struct paravirt_patch_site size"
[[ -z "$ORC_STRUCT_SIZE" && "$CONFIG_UNWINDER_ORC" -ne 0 ]] && die "can't find special struct orc_entry size" [[ -z "$ORC_STRUCT_SIZE" && "$CONFIG_UNWINDER_ORC" -ne 0 ]] && die "can't find special struct orc_entry size"
[[ -z "$JUMP_STRUCT_SIZE" && "$CONFIG_JUMP_LABEL" -ne 0 ]] && die "can't find special struct jump_entry size"
return return
} }
@ -726,11 +714,6 @@ if grep -q "CONFIG_UNWINDER_ORC=y" "$CONFIGFILE"; then
else else
CONFIG_UNWINDER_ORC=0 CONFIG_UNWINDER_ORC=0
fi fi
if grep -q "CONFIG_JUMP_LABEL=y" "$CONFIGFILE"; then
CONFIG_JUMP_LABEL=1
else
CONFIG_JUMP_LABEL=0
fi
# unsupported kernel option checking # unsupported kernel option checking
grep -q "CONFIG_DEBUG_INFO_SPLIT=y" "$CONFIGFILE" && die "kernel option 'CONFIG_DEBUG_INFO_SPLIT' not supported" grep -q "CONFIG_DEBUG_INFO_SPLIT=y" "$CONFIGFILE" && die "kernel option 'CONFIG_DEBUG_INFO_SPLIT' not supported"

2
test/unit/objs

@ -1 +1 @@
Subproject commit 3f91f6940e8eb71864a90970ef88d73c30966796 Subproject commit 9a5663f9b52f6f99036185fa1a8e73ab6496abda