Re: [PATCH 1/4] kprobes: adjust kprobe addr for KPROBES_ON_FTRACE

From: Naveen N. Rao
Date: Mon Aug 19 2019 - 12:43:15 EST

Jisheng Zhang wrote:
For KPROBES_ON_FTRACE case, we need to adjust the kprobe's addr

Signed-off-by: Jisheng Zhang <Jisheng.Zhang@xxxxxxxxxxxxx>
kernel/kprobes.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 9873fc627d61..f8400753a8a9 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1560,6 +1560,9 @@ int register_kprobe(struct kprobe *p)
addr = kprobe_addr(p);
if (IS_ERR(addr))
return PTR_ERR(addr);
+ addr = (kprobe_opcode_t *)ftrace_call_adjust((unsigned long)addr);
p->addr = addr;

I'm not sure what this is achieving, but looks wrong to me.

If you intend to have kprobes default to using ftrace entry for probing functions, consider over-riding kprobe_lookup_name() -- see powerpc variant for example.

- Naveen