[PATCH -tip v5 09/12] kprobes: Setup instruction pointer in __kretprobe_trampoline_handler

Masami Hiramatsu
2021-03-26T12:30:10Z

To simplify the stacktrace with pt_regs from kretprobe handler,
set the correct return address to the instruction pointer in
the pt_regs before calling kretprobe handlers.

Suggested-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
Changes in v3:
- Cast the correct_ret_addr to unsigned long.
---
kernel/kprobes.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index cf19edc038e4..4ce3e6f5d28d 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1914,6 +1914,9 @@ unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs,
BUG_ON(1);
}

+ /* Set the instruction pointer to the correct address */
+ instruction_pointer_set(regs, (unsigned long)correct_ret_addr);
+
/* Run them. */
first = current->kretprobe_instances.first;
while (first) {