diff options
| author | Masami Hiramatsu (Google) <mhiramat@kernel.org> | 2024-10-21 21:39:22 +0900 |
|---|---|---|
| committer | Masami Hiramatsu (Google) <mhiramat@kernel.org> | 2024-11-07 01:16:59 +0900 |
| commit | 4638d7ebeff5a741e22139cf00aaa9db0f668a8c (patch) | |
| tree | 1521ebcbac9c04dedcf1aec19221f601df68a9ad /arch/x86/kernel | |
| parent | 3fbff988892993a144d0f47db0348c18b4621393 (diff) | |
x86/kprobes: Cleanup kprobes on ftrace code
Cleanup kprobes on ftrace code for x86.
- Set instruction pointer (ip + MCOUNT_INSN_SIZE) after pre_handler only
when p->post_handler exists.
- Use INT3_INSN_SIZE instead of 1.
- Use instruction_pointer/instruction_pointer_set() functions instead of
accessing regs->ip directly.
Link: https://lore.kernel.org/all/172951436219.167263.18330240454389154327.stgit@devnote2/
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Diffstat (limited to 'arch/x86/kernel')
| -rw-r--r-- | arch/x86/kernel/kprobes/ftrace.c | 19 |
1 files changed, 11 insertions, 8 deletions
diff --git a/arch/x86/kernel/kprobes/ftrace.c b/arch/x86/kernel/kprobes/ftrace.c index 15af7e98e161..2be55ec3f392 100644 --- a/arch/x86/kernel/kprobes/ftrace.c +++ b/arch/x86/kernel/kprobes/ftrace.c @@ -9,6 +9,7 @@ #include <linux/hardirq.h> #include <linux/preempt.h> #include <linux/ftrace.h> +#include <asm/text-patching.h> #include "common.h" @@ -36,23 +37,25 @@ void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip, if (kprobe_running()) { kprobes_inc_nmissed_count(p); } else { - unsigned long orig_ip = regs->ip; + unsigned long orig_ip = instruction_pointer(regs); + /* Kprobe handler expects regs->ip = ip + 1 as breakpoint hit */ - regs->ip = ip + sizeof(kprobe_opcode_t); + instruction_pointer_set(regs, ip + INT3_INSN_SIZE); __this_cpu_write(current_kprobe, p); kcb->kprobe_status = KPROBE_HIT_ACTIVE; if (!p->pre_handler || !p->pre_handler(p, regs)) { - /* - * Emulate singlestep (and also recover regs->ip) - * as if there is a 5byte nop - */ - regs->ip = (unsigned long)p->addr + MCOUNT_INSN_SIZE; if (unlikely(p->post_handler)) { + /* + * Emulate singlestep (and also recover regs->ip) + * as if there is a 5byte nop + */ + instruction_pointer_set(regs, ip + MCOUNT_INSN_SIZE); kcb->kprobe_status = KPROBE_HIT_SSDONE; p->post_handler(p, regs, 0); } - regs->ip = orig_ip; + /* Recover IP address */ + instruction_pointer_set(regs, orig_ip); } /* * If pre_handler returns !0, it changes regs->ip. We have to |