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error-injection: Fix to prohibit jump optimization 

Since the kprobe which was optimized by jump can not change
the execution path, the kprobe for error-injection must not
be optimized. To prohibit it, set a dummy post-handler as
officially stated in Documentation/kprobes.txt.

Fixes: 4b1a29a7f5 ("error-injection: Support fault injection framework")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Masami Hiramatsu 2018-03-12 19:00:49 +09:00 committed by Daniel Borkmann
parent 9e5fb72070
commit b6b76dd62c
1 changed files with 10 additions and 0 deletions
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10
kernel/fail_function.c
View File

@ -14,6 +14,15 @@
static int fei_kprobe_handler(struct kprobe *kp, struct pt_regs *regs);
static void fei_post_handler(struct kprobe *kp, struct pt_regs *regs,
unsigned long flags)
{
/*
* A dummy post handler is required to prohibit optimizing, because
* jump optimization does not support execution path overriding.
*/
}
struct fei_attr {
struct list_head list;
struct kprobe kp;
@ -56,6 +65,7 @@ static struct fei_attr *fei_attr_new(const char *sym, unsigned long addr)
return NULL;
}
attr->kp.pre_handler = fei_kprobe_handler;
attr->kp.post_handler = fei_post_handler;
attr->retval = adjust_error_retval(addr, 0);
INIT_LIST_HEAD(&attr->list);
}