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Commit b6b76dd6 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Daniel Borkmann
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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: 4b1a29a7 ("error-injection: Support fault injection framework")
Signed-off-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent 9e5fb720

kernel/fail_function.c

+10 −0
Original line number Diff line number Diff line
@@ -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);

	}