(2013/04/03 17:28), [email protected] wrote: > > +/* it can take some time ( > 100ms ) to initialise the > + * blacklist so we delay this until we actually need it > + */ > +static void init_kprobe_blacklist(void) > +{ > + int i; > + unsigned long offset = 0, size = 0; > + char *modname, namebuf[128]; > + const char *symbol_name; > + void *addr; > + struct kprobe_blackpoint *kb; > + > + /* > + * Lookup and populate the kprobe_blacklist. > + * > + * Unlike the kretprobe blacklist, we'll need to determine > + * the range of addresses that belong to the said functions, > + * since a kprobe need not necessarily be at the beginning > + * of a function. > + */ > + for (kb = kprobe_blacklist; kb->name != NULL; kb++) { > + kprobe_lookup_name(kb->name, addr); > + if (!addr) > + continue; > + > + kb->start_addr = (unsigned long)addr; > + symbol_name = kallsyms_lookup(kb->start_addr, > + &size, &offset, &modname, namebuf); > + if (!symbol_name) > + kb->range = 0; > + else > + kb->range = size; > + } > + > + if (kretprobe_blacklist_size) { > + /* lookup the function address from its name */ > + for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { > + kprobe_lookup_name(kretprobe_blacklist[i].name, > + kretprobe_blacklist[i].addr); > + if (!kretprobe_blacklist[i].addr) > + printk("kretprobe: lookup failed: %s\n", > + kretprobe_blacklist[i].name); > + } > + } > + kprobe_blacklist_initialized = 1; > +} > + > #ifdef __ARCH_WANT_KPROBES_INSN_SLOT > /* > * kprobe->ainsn.insn points to the copy of the instruction to be > @@ -1331,6 +1379,9 @@ static int __kprobes in_kprobes_functions(unsigned long > addr) > if (addr >= (unsigned long)__kprobes_text_start && > addr < (unsigned long)__kprobes_text_end) > return -EINVAL; > + > + if (!kprobe_blacklist_initialized) > + init_kprobe_blacklist(); > /* > * If there exists a kprobe_blacklist, verify and > * fail any probe registration in the prohibited area > @@ -1816,6 +1867,8 @@ int __kprobes register_kretprobe(struct kretprobe *rp) > void *addr; > > if (kretprobe_blacklist_size) { > + if (!kprobe_blacklist_initialized) > + init_kprobe_blacklist();
Joonsoo reminds me that these calling points are not protected by kprobe_mutex, thus we have to do something for avoiding concurrent initialization. Perhaps, the easiest way is to protect init_kprobe_blacklist() by kprobe_mutex and check kprobe_blacklist_initialized again in the top of that. Thank you, -- Masami HIRAMATSU IT Management Research Dept. Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: [email protected] -- 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/
