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Merge pull request #590 from euspectre/paravirt-alt-reloc-fix 

kmod/core: Skip relocations of already altered instructions
This commit is contained in:
Jessica Yu 2016-04-11 10:41:37 -07:00
parent 7eda8dab6d 8dac9d0871
commit d2d1f639b2
1 changed files with 14 additions and 0 deletions
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14
kmod/core/core.c
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@ -43,6 +43,7 @@
#include <linux/uaccess.h>
#include <linux/kallsyms.h>
#include <linux/version.h>
#include <linux/string.h>
#include <asm/stacktrace.h>
#include <asm/cacheflush.h>
#include "kpatch.h"
@ -650,6 +651,19 @@ static int kpatch_write_relocations(struct kpatch_module *kpmod,
return -EINVAL;
}
/*
* Skip it if the instruction to be relocated has been
* changed already (paravirt or alternatives may do this).
*/
if (memchr_inv((void *)loc, 0, size)) {
pr_notice("Skipped dynrela for %s (0x%lx <- 0x%lx): the instruction has been changed already.\n",
dynrela->name, dynrela->dest, dynrela->src);
pr_notice_once(
"This is not necessarily a bug but it may indicate in some cases "
"that the binary patch does not handle paravirt operations, alternatives or the like properly.\n");
continue;
}
#ifdef CONFIG_DEBUG_SET_MODULE_RONX
#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 5, 0)
if (loc < core + kpmod->mod->core_layout.ro_size)