On Tue, Apr 1, 2014 at 4:08 PM, Rabin Vincent <[email protected]> wrote: > 2014-04-01 20:36 GMT+02:00 Kees Cook <[email protected]>: >> Is there something "sticky" about PMD sections that I'm not aware of? >> Even after calling set_kernel_text_rw(), any writes to kernel memory >> fault. :( > > section_update() updates init_mm, but each mm has a copy of the first > level page tables. So your updates to init_mm won't be visibile to > currently running processes. (Have a look at arch/arm/mm/ioremap.c's > vmalloc_seq stuff for some background on how section support is > handled on non-SMP; the vmalloc code doesn't use sections on SMP.)
Ah-ha! This is the missing piece of information for me. :) > Here's a patch (probably whitespace damaged, hence also attached) with > which dynamic ftrace works for me on top your other paches. Tested on > a non-LPAE SMP. Thanks! I'll incorporate calls to set_all_modules_text_rw/ro and see what I can make work. -Kees -- Kees Cook Chrome OS Security -- 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/
