__recover_probed_insn() should always be called from an address where an instructions starts. The check for ftrace_location() might help to discover a potential inconsistency. Something goes terribly wrong when an address inside the ftrace location is checked. Let's BUG() in this case.
Suggested-by: Masami Hiramatsu <[email protected]> Signed-off-by: Petr Mladek <[email protected]> --- arch/x86/kernel/kprobes/core.c | 6 ++++++ 1 file changed, 6 insertions(+) This is follow up for the patch ("[PATCH v2] kprobes/x86: Use 5-byte NOP when the code might be modified by ftrace") based on the Masami's suggestion, see https://lkml.org/lkml/2015/2/3/207 Let me know if I should merge this with the first patch and send v3. diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index 2f464b56766a..124577dcf768 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -228,6 +228,12 @@ __recover_probed_insn(kprobe_opcode_t *buf, unsigned long addr) kp = get_kprobe((void *)addr); faddr = ftrace_location(addr); /* + * Addresses inside the ftrace location are refused by + * arch_check_ftrace_location(). Something went terribly wrong + * if such an address is checked here. + */ + BUG_ON(faddr && faddr != addr); + /* * Use the current code if it is not modified by Kprobe * and it cannot be modified by ftrace. */ -- 1.8.5.6 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
