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create-diff-object: allow dynamic debug static keys

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While static keys (jump labels) are currently broken in livepatch, a
broken dynamic debug static key is harmless since it just disables
dynamically enabled debug printks in the patched code.

Fixes: #1021

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
This commit is contained in:
Josh Poimboeuf 2019-08-15 08:28:56 -05:00
parent 1fe8fe66c2
commit 2975775768
2 changed files with 21 additions and 6 deletions
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25
kpatch-build/create-diff-object.c
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@ -237,6 +237,15 @@ static void kpatch_detect_child_functions(struct kpatch_elf *kelf)
}
}
static bool is_dynamic_debug_symbol(struct symbol *sym)
{
if (sym->type == STT_OBJECT && !strcmp(sym->sec->name, "__verbose"))
return true;
if (sym->type == STT_SECTION && !strcmp(sym->name, "__verbose"))
return true;
return false;
}
/*
* This function detects whether the given symbol is a "special" static local
* variable (for lack of a better term).
@ -261,8 +270,7 @@ static int is_special_static(struct symbol *sym)
return 0;
/* pr_debug() uses static local variables in the __verbose section */
if ((sym->type == STT_OBJECT && !strcmp(sym->sec->name, "__verbose")) ||
(sym->type == STT_SECTION && !strcmp(sym->name, "__verbose")))
if (is_dynamic_debug_symbol(sym))
return 1;
if (sym->type == STT_SECTION) {
@ -2104,9 +2112,16 @@ static void kpatch_regenerate_special_section(struct kpatch_elf *kelf,
if (i != 3)
ERROR("BUG: __jump_table has an unexpected format");
if (strncmp(key->sym->name, "__tracepoint_", 13))
ERROR("Found a jump label at %s()+0x%x, using key %s. Jump labels aren't currently supported. Use static_key_enabled() instead.",
code->sym->name, code->addend, key->sym->name);
/* inert tracepoints are harmless */
if (!strncmp(key->sym->name, "__tracepoint_", 13))
continue;
/* inert dynamic debug printks are harmless */
if (is_dynamic_debug_symbol(key->sym))
continue;
ERROR("Found a jump label at %s()+0x%x, using key %s. Jump labels aren't currently supported. Use static_key_enabled() instead.",
code->sym->name, code->addend, key->sym->name);
continue;
}

2
test/unit/objs

@ -1 +1 @@
Subproject commit 0b34cbb7e835706615d2295f8c3129a23e19f6e6
Subproject commit 510a90ca8d35c09574d449ea0f171a7a9baaf087