On Fri 2015-02-20 13:52:23, Ingo Molnar wrote: > > * Masami Hiramatsu <[email protected]> wrote: > > > (2015/02/20 19:26), Ingo Molnar wrote: > > > > > > * Petr Mladek <[email protected]> wrote: > > > > > >> can_probe() checks if the given address points to the > > >> beginning of an instruction. It analyzes all the > > >> instructions from the beginning of the function until the > > >> given address. The code might be modified by another > > >> Kprobe. In this case, the current code is read into a > > >> buffer, int3 breakpoint is replaced by the saved opcode > > >> in the buffer, and can_probe() analyzes the buffer > > >> instead. > > >> > > >> [...] > > > > > > Had to drop this patch due to build failures on 32-bit x86: > > > > > > arch/x86/kernel/kprobes/core.c:258:40: error: ‘MCOUNT_INSN_SIZE’ > > > undeclared (first use in this function) > > > > Oops, MCOUNT_INSN_SIZE actually depends on > > CONFIG_FUNCTION_TRACER... I think we can use 5 instead of > > that since we are copying.
I'll use 5 for now. > Or just make the define more widely available? It's not > like the size changes from disabling the function tracer. I would do this in a separate patch that would consolidate all NOP_ATOMIC5 users: ftrace, jump_labels, and kprobe. The number 5 is hardcoded more times in arch/x86/kernel/kprobes/core.c. I'll put it into my TODO list. Best Regards, Petr -- 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/
