Masami Hiramatsu píše v Čt 14. 11. 2013 v 20:36 +0900: > (2013/11/14 19:41), Petr Mladek wrote: > > @@ -837,7 +882,7 @@ static void recover_iter(struct text_poke_bp_iter > > *iterator, > > } > > > > /* Finally, put back the first byte from the old code */ > > - err = text_poke(addr, old_opcode, sizeof(bp_int3)); > > + err = text_poke_part(addr, old_opcode, sizeof(bp_int3)); > > /* we can not continue if the interrupt is still there */ > > BUG_ON(err); > > } > > @@ -865,7 +910,9 @@ static void recover_iter(struct text_poke_bp_iter > > *iterator, > > * It is a bit more paranoid than text_poke_bp because it checks the actual > > * code before patching. This is a good practice proposed by the ftrace > > code. > > * > > - * Note: This function must be called under text_mutex. > > + * Note: This function must be called under text_mutex. Also the caller is > > + * responsible for making the patched code read-write, for example using > > + * set_kernel_text_rw() and set_all_modules_text_rw() > > OK, I got the reason why we can do it. > But if so, we should change all existing caller of text_poke_bp() to > call it in this patch, or they must fail at this point.
Ah, I used "text_poke_part" only in "text_poke_bp_iter" in the end. This function is currently used only in ftrace that sets the code read-write in "ftrace_arch_code_modify_prepare", see arch/x86/kernel/ftrace.c. Note that "text_poke_bp" still uses "text_poke". It seems that the remapping is faster if you patch only one address. So, we should be on the safe side. Thanks a lot for review. Best Regards, Petr -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
