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: 4b1a29a7f542 ("error-injection: Support fault injection framework")
Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
---
kernel/fail_function.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/kernel/fail_function.c b/kernel/fail_function.c
index 21b0122cb39c..1d5632d8bbcc 100644
--- a/kernel/fail_function.c
+++ b/kernel/fail_function.c
@@ -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);
}
--
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